diff --git a/.formatter.exs b/.formatter.exs
index d2cda26..5e3c114 100644
--- a/.formatter.exs
+++ b/.formatter.exs
@@ -1,4 +1,17 @@
 # Used by "mix format"
 [
-  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+  plugins: [Volt.Formatter],
+  inputs: [
+    "{mix,.formatter}.exs",
+    "{config,lib,test}/**/*.{ex,exs}",
+    "priv/ts/{client,compilers,test}/**/*.ts"
+  ],
+  volt: [
+    trailing_comma: :none,
+    tab_width: 2,
+    semi: false,
+    single_quote: true,
+    print_width: 100,
+    arrow_parens: :always
+  ]
 ]
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..b66b59e
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1 @@
+priv/ts/npm.lock linguist-generated
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..786f701
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,28 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  elixir:
+    uses: elixir-vibe/actions/.github/workflows/elixir-ci.yml@v1
+    with:
+      latest-elixir: "1.20"
+      latest-otp: "29"
+      min-elixir: "1.18"
+      min-otp: "27"
+      deps-command: |
+        sudo apt-get update
+        sudo apt-get install --yes inotify-tools
+        mix deps.get
+        mix volt.priv.vendor priv/ts
+        npm ci
+        npx playwright install --with-deps chromium
+      latest-command: MIX_ENV=dev mix lint && MIX_ENV=test mix test
+      min-command: mix compile --warnings-as-errors && mix test
diff --git a/.gitignore b/.gitignore
index c6598cf..21b1a10 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,3 +30,4 @@ volt-*.tar
 
 # Git worktrees for parallel agent work
 .worktrees/
+/priv/ts/node_modules/
diff --git a/.reach.exs b/.reach.exs
index 979759b..96382fd 100644
--- a/.reach.exs
+++ b/.reach.exs
@@ -10,17 +10,19 @@ compat_json = [":json.*"]
 unsafe_runtime_encoding = ["Jason.encode!"]
 unstable_hashing = [":erlang.phash2"]
 builder_runtime = ["Volt.DevServer.*", "Volt.Watcher.*", "Volt.HMR.*"]
-asset_runtime = ["Volt.Assets.*", "Volt.Builder.*", "Volt.DevServer.*", "Volt.JS.*"]
+asset_runtime = ["Volt.Assets.*", "Volt.Builder.*", "Volt.DevServer.*", "Volt.JS.*", "Volt.NPM"]
 ast_side_effects = app_config ++ file_mutation ++ ["System.cmd", "QuickBEAM.*"] ++ builder_runtime
 
 adapter = [
   "Mix.Tasks.Volt.*",
   "Volt",
   "Volt.Formatter",
+  "Volt.NPM",
   "Volt.Test.*"
 ]
 
 orchestrator = [
+  "Volt.Build",
   "Volt.Builder",
   "Volt.Builder.Collector",
   "Volt.Builder.Compiler",
@@ -32,25 +34,36 @@ orchestrator = [
   "Volt.JS.Vendor",
   "Volt.Pipeline",
   "Volt.Tailwind",
-  "Volt.Watcher"
+  "Volt.Tailwind.Build",
+  "Volt.Watcher",
+  "Volt.Dev.Session.Watcher",
+  "Volt.Watcher.Ignore",
+  "Volt.Watcher.Path"
 ]
 
 model = [
   "Volt.Builder.BuildContext",
+  "Volt.Builder.Asset",
   "Volt.Builder.Bundle",
   "Volt.Builder.Collector.State",
   "Volt.Builder.Context",
+  "Volt.Builder.Compiled",
   "Volt.Builder.Dependencies",
   "Volt.Builder.ManifestEntry",
   "Volt.Builder.OutputContext",
   "Volt.Builder.OutputFile",
   "Volt.Builder.Result",
+  "Volt.Build.Result",
+  "Volt.Build.Layout",
+  "Volt.Config.Tailwind",
   "Volt.ChunkGraph.Chunk",
   "Volt.Config",
   "Volt.Config.*",
+  "Volt.Dev.Session.Tables",
   "Volt.DevServer.CacheEntry",
   "Volt.DevServer.Config",
   "Volt.HMR.Message",
+  "Volt.HMR.Channel",
   "Volt.JS.ImportExtractor.Result",
   "Volt.JS.PrebundleEntry.Export",
   "Volt.JS.PrebundleEntry.Import",
@@ -58,12 +71,23 @@ model = [
   "Volt.JS.TSConfig",
   "Volt.MIME",
   "Volt.Paths",
-  "Volt.Pipeline.Result.Hashes"
+  "Volt.Pipeline.Result.Hashes",
+  "Volt.Tailwind.CompileError",
+  "Volt.Tailwind.ResolveError",
+  "Volt.Tailwind.Context",
+  "Volt.Tailwind.Metadata",
+  "Volt.Tailwind.State",
+  "Volt.Tailwind.Compilation"
 ]
 
 logic = [
+  "Volt.Builder.Artifact",
+  "Volt.Builder.CSS.Prepared",
+  "Volt.Builder.Declarations",
+  "Volt.Builder.Plan",
   "Volt.Assets",
   "Volt.Assets.Query",
+  "Volt.Builder.Naming",
   "Volt.Builder.Resolver",
   "Volt.ChunkGraph",
   "Volt.CSS.AST",
@@ -73,12 +97,16 @@ logic = [
   "Volt.CSS.Modules",
   "Volt.Env",
   "Volt.Format",
+  "Volt.HMR.Document",
   "Volt.HTMLEntry",
   "Volt.JS.AST",
   "Volt.JS.Check",
+  "Volt.JS.CommonJS",
+  "Volt.JS.Lint.Config",
+  "Volt.JS.Lint.TSConfigOverlay",
   "Volt.JS.Extensions",
   "Volt.JS.Format",
-  "Volt.JS.Helpers",
+  "Volt.JS.Discovery",
   "Volt.JS.ImportExtractor",
   "Volt.JS.Package",
   "Volt.JS.Patch",
@@ -111,12 +139,24 @@ infrastructure = [
   "Volt.Application",
   "Volt.Builder.CSS",
   "Volt.Builder.Writer",
+  "Volt.Builder.Publication",
   "Volt.Cache",
   "Volt.Dev",
+  "Volt.Dev.Cleanup",
+  "Volt.Dev.Prebundled",
+  "Volt.Dev.Error",
+  "Volt.Priv.Vendor",
+  "Volt.DevServer.ClientTag",
+  "Volt.Dev.Assets",
+  "Volt.Dev.Session.Call",
+  "Volt.Dev.Session.State",
+  "Volt.Dev.Session.Supervisor",
   "Volt.Dev.ConsoleForwarder",
   "Volt.Dev.ConsoleForwarder.Payload",
   "Volt.ETS",
   "Volt.HMR.Boundary",
+  "Volt.HMR.Documents",
+  "Volt.HMR.Errors",
   "Volt.HMR.GlobGraph",
   "Volt.HMR.ImportGraph",
   "Volt.HMR.ModuleGraph",
@@ -131,7 +171,12 @@ infrastructure = [
   "Volt.JS.Runtime.Entry",
   "Volt.JS.Runtime.Error",
   "Volt.JS.Runtime.Installer",
-  "Volt.Tailwind.Loader"
+  "Volt.JS.Runtime.PackageSet",
+  "Volt.Tailwind.Artifact",
+  "Volt.Tailwind.Loader",
+  "Volt.Tailwind.Runtime",
+  "Volt.Tailwind.Supervisor",
+  "Volt.Tailwind.Worker"
 ]
 
 plugin = [
diff --git a/AGENTS.md b/AGENTS.md
index a17e330..ea133ec 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -1,3 +1,7 @@
 # Project Guidelines
 
+- Match primary Elixir module namespaces to their source paths. Nested data modules, protocol implementations, conditional definitions, and established acronym spellings are deliberate exceptions.
+- Mirror source paths and namespaces in unit tests. Keep cross-module scenarios under the owning subsystem or integration directory; do not invent a production module merely to match a scenario test.
+- Keep Mix tasks in nested `lib/mix/tasks/` paths as `.ex`, tests as `_test.exs`, and shared support as `.ex` under `test/support/`, compiled only in the test environment. `lib/volt/test/` contains shipped framework APIs, not project test support.
+
 - Prefer parser/AST-backed solutions over hand-rolled regular expressions for source code, markup, and structured formats. Use existing parsers such as OXC for JavaScript/TypeScript and Floki for HTML-like markup when available.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index b7f928a..bfa34bc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,288 @@
 # Changelog
 
-## Unreleased
+## 0.23.0 - 2026-10-08
+
+### Added
+
+- `mix volt.build --declarations` and `config :volt, declarations: true` write a library's type declarations with its bundle: one `<name>.d.ts` per entry, beside it and without a hash, holding what the entry exports and the types those exports reach. Modules are emitted through OXC's isolated declarations (oxc 0.19), so exported declarations need explicit types and the build fails naming the module that lacks them; the declarations are then bundled as `rollup-plugin-dts` does, with types-only modules included, imports of other packages hoisted, and same-named declarations of different modules told apart. `.vue` modules are declared by the Vue plugin ([#71](https://github.com/elixir-volt/volt/issues/71)).
+
+### Changed
+
+- Require oxc 0.19 and quickbeam 0.11.3.
+
+## 0.22.1 - 2026-10-07
+
+### Fixed
+
+- Start Volt's application before the browser a test run shares, which lives under its supervisor. A project that depends on Volt with `runtime: false` had to start it in `test_helper.exs`, or browser tests failed with `Volt.Supervisor` not running.
+
+## 0.22.0 - 2026-10-07
+
+### Added
+
+- `mix volt.js.check --type-aware` types imports of `.vue` files by the component's own declaration. The Vue plugin generates it from each checked `.vue` file with `Vize.generate_dts/2` and Volt sends it to tsgolint as `<file>.vue.d.ts`, which TypeScript resolves an import of the `.vue` file to. Props, emits and slots of imported components are then checked in `h(Button, {...})` and `InstanceType<typeof Button>`, and no `declare module "*.vue"` shim is needed for checked files. Plugins declare their own files through the new `c:Volt.Plugin.declaration/3` callback ([#63](https://github.com/elixir-volt/volt/issues/63)).
+
+### Changed
+
+- Browser tests share one browser per run, in `Volt.Test.Browser`, and each test gets a browser context of its own. Every test started a Playwright driver and launched a browser for itself, because the driver was linked to the test process and went away with it, which cost more than running the test. A test file is now bundled once for all of its tests and bundled again only when one of its source files changes, and the ExUnit modules generated for browser tests are `async: true` ([#65](https://github.com/elixir-volt/volt/issues/65)).
+
+### Fixed
+
+- Give vendor modules a new URL when a package changes. The dev server serves `/@vendor/<package>.js?v=<hash>` as immutable, and the hash covered the lockfiles and plugins but not the packages, so a package that changed in place, such as a linked one, kept its URL and browsers kept their copy of it. The hash now also covers the generation of the pre-bundle, which changes whenever a package is bundled again, and a compiled application module is compiled again when the hash it was compiled with is no longer current: after a lockfile change, unchanged modules kept importing the old URL, which answered 504. Packages linked from outside `node_modules` are watched, and a change bundles them again and reloads the page. `npm.lock`, the lockfile of `mix npm.install`, now counts as a lockfile; it was not read, so an install did not change the URL either ([#67](https://github.com/elixir-volt/volt/issues/67)).
+- Treat Node built-in subpaths such as `timers/promises`, `fs/promises` and `stream/web` as built-ins, and read the `browser` field of packages. Bundling a package that requires `timers/promises`, such as `@sinonjs/fake-timers`, failed with `{:not_found, "timers/promises"}` even though its `browser` field maps the specifier to `false`. Specifiers a `browser` field maps to `false` now resolve to an empty module, and those mapped to a path resolve to that path, as in esbuild and webpack. The builder, the dev server and the Tailwind resolver share the built-in check ([#64](https://github.com/elixir-volt/volt/issues/64)).
+
+## 0.21.0 - 2026-10-05
+
+### Compatibility
+
+- Require vize 0.17.1, which fixes three Vapor compiler bugs. Two can affect components compiled with `vapor: true`: static attribute values were decoded twice in Vapor templates, and default slot content beside a named `<template #name>` was dropped. Volt's use of vize is unchanged.
+
+### Added
+
+- `plug Volt.DevServer, document: {module, function, args}` lets the dev server render pages itself. With `:morph`, each open page's websocket process keeps the HTML the server last rendered for it, renders the page again when a template or content file changes, and compares the two renders. A page is then sent only what applies to it: nothing, a reload, or the new HTML to patch. Pages no longer request themselves to find out.
+- With `:document`, the attributes the server changed on `<html>` and `<body>` and the metadata and links it changed in `<head>` are applied too. Attributes that scripts set on those elements, such as a theme, are left alone, because the comparison only sees what the server rendered.
+- When the server changed the attributes of an element matched by `morph: [preserve: selector]`, such as the props of a mounted component, the client sets them and dispatches a cancelable `volt:element-update` event on the element instead of reloading. The page reloads only if nothing handles the event.
+
+### Fixed
+
+- Leave Vue `<script>` blocks in other languages, such as `<script lang="elixir">`, out of the script modules that `mix volt.js.check` lints and type-checks. Every block was treated as JavaScript, so such a block was reported as TypeScript syntax errors. `lang="jsx"` blocks are now checked as JSX ([#57](https://github.com/elixir-volt/volt/issues/57)).
+- Serve the `@oxc-project/runtime` helpers that the dev server's own output imports. With a `:target` below ES2022, a class with fields compiles to an import of such a helper, which `/@vendor/` answered with 404 unless the npm package was installed, so the importing module and everything importing it failed to load with no error shown. The helpers now come from the bundler, as in production builds ([#58](https://github.com/elixir-volt/volt/issues/58)).
+- Type-check the scripts of `.vue` and `.svelte` files with the project's `tsconfig.json`. `mix volt.js.check --type-aware --type-check` checked them in a project of their own with default options, so imports through `paths` aliases and of other components failed with TS2307 even with a `declare module "*.vue"` declaration ([#60](https://github.com/elixir-volt/volt/issues/60)).
+- Stop the dev server scanning sources and pre-bundling packages on every request. Phoenix initializes plugs per request in development, and one import that resolves to no package, such as one the page provides, made every request bundle all packages again, with concurrent requests replacing cache files others were reading. Pre-bundling now runs once and again after a source file changes, requests take turns, and unresolvable imports no longer count as stale ([#59](https://github.com/elixir-volt/volt/issues/59)).
+- Resolve the dev server's paths from the directory Volt started in, not the current working directory. `Phoenix.CodeReloader` changes the VM's working directory while it compiles a reloadable path dependency, so a vendor request served at the same time wrote its cache into the dependency's `_build`, or failed with `could not write to file`. The vendor cache, asset root, watched directories and Tailwind input are affected ([#56](https://github.com/elixir-volt/volt/issues/56)).
+
+## 0.20.0 - 2026-10-03
+
+### Breaking changes
+
+- Formatter options moved from `config :volt, :format` to the `:volt` key of `.formatter.exs`, where `mix format` plugins keep their options. `config :volt, :format` now only holds the build output format (`:iife`, `:esm`, or `:cjs`), so both can be set. A keyword list under `config :volt, :format` raises an `ArgumentError` with the options to move:
+
+      # .formatter.exs
+      [
+        plugins: [Volt.Formatter],
+        volt: [semi: false, single_quote: true]
+      ]
+
+  The formatting-only `:root`, `:sources`, and `:ignore` overrides for `mix volt.js.format` and `mix volt.js.check` move to the same key. `.oxfmtrc.json` and `.prettierrc.json` are still read when there is no `:volt` key. `mix igniter.install volt` writes the options to `.formatter.exs`.
+- External modules stay as imports in `:esm` and `:cjs` output, as in Rollup, Rolldown, esbuild and Bun. With `format: :esm, external: ["phoenix"]`, `import { Socket } from "phoenix"` used to become `const { Socket } = Phoenix;`; it is now left for the browser or host to resolve, for example through an import map. `:cjs` output uses `require("phoenix")`. IIFE output, the default, still reads externals from globals. The global names in `external: %{"phoenix" => "Phoenix"}` apply to IIFE output only. ESM builds that relied on page globals need an import map or `format: :iife`.
+- `Volt.JS.Format.load_config/1` takes the `.formatter.exs` options instead of reading the application environment.
+
+### Compatibility
+
+- Require vize 0.17. Volt's use of vize is unchanged: 0.17 replaces `Vize.vapor_split/1` with `Vize.split_template/2`, which Volt doesn't call. Projects that depend on vize themselves need 0.17 alongside this release.
+
+### Added
+
+- Changes in `reload_dirs` reload only the pages whose HTML changed. The watcher broadcasts a `document` update for them instead of a `full` one. Pages carry an entity tag of their rendered HTML; on a change the dev client revalidates with `If-None-Match` and reloads unless the server answers `304 Not Modified`. Editing one post no longer reloads every open tab, and a save that does not change a page's output reloads nothing. This covers every successful HTML response that passes through `Volt.DevServer`, including pages that already load the dev client, so site generators built on Volt need no change. `Volt.HMR.document_update/2` sends the same request from other packages, and `Volt.HMR.Document` describes the contract for servers that send HTML some other way.
+- `config :volt, :server, morph: true` patches a changed page in place instead of reloading it, so scroll position, focus and JavaScript state survive edits to text and classes. The client reloads as before when scripts or stylesheets differ. `morph: [preserve: selector]` names elements owned by client code, such as mounted components, which are left alone. The client dispatches `volt:document-updated` after a patch.
+- Stylesheet updates no longer flash unstyled content. The dev client adds a `<link>` for the updated stylesheet and removes the previous one once the new one has loaded, instead of changing `href` in place.
+- The dev client reloads the page once when several updates ask for a reload at the same time, such as a template that is also a Tailwind source.
+- The dev server converts local CommonJS and UMD files, such as Phoenix's vendored `topbar.js`, to ES modules, so `import topbar from "../vendor/topbar"` works in development as it does in production builds. `.cjs` and `.cts` files, which the dev server did not serve, are converted the same way.
+- Relative `watch_ignored` patterns also resolve from the project directory, so `_build/**` matches a watched directory inside `_build`.
+- Volt's client types declare `import.meta.env`, so TypeScript projects no longer need their own `ImportMeta` declaration for `MODE`, `DEV`, `PROD` and exposed variables. `mix igniter.install volt` adds `env.d.ts` to configurations that list declaration files explicitly.
+
+### Fixed
+
+- Collect every test generated by `test.each` and `describe.each`. Source lines were matched to tests by position, and tests without a detected line were dropped: a five-case table followed by two tests collected as two tests. Each case now maps to the line of its table, and tests registered in ways the source does not show, such as in a loop, are kept without a line.
+- Stop the dev server reloading pages in a loop when a watched file is rewritten with identical content, as Phoenix LiveView does for colocated hooks on every code reload. The watcher now compares file contents before rebuilding.
+- Load a single instance of each pre-bundled dependency in development. Pre-bundles imported their siblings and shared chunks without the `?v=` hash that application modules use, so browsers loaded packages such as Vue twice and component libraries built on them failed to render.
+- Report why a development session is unavailable. A second watcher with different options, such as a `Mix.Tasks.Volt.Dev` entry in the endpoint's `:watchers` next to `plug Volt.DevServer`, answered every request with a bare 503; the response and the log now name the conflict and how to resolve it.
+- Log `Pre-bundled N vendor package(s)` only when packages are bundled. Phoenix initializes plugs on every request in development, so it was logged per request.
+- Read external globals once in code-split IIFE output. Each chunk also declared them at the top level of the script, where two chunks importing the same name would clash.
+- Stop watchers before the Tailwind processes they release their contexts to. Volt's supervisor stopped the Tailwind registry first, so every watcher with Tailwind enabled crashed with `unknown registry: Volt.Tailwind.Registry` on shutdown.
+- Skip `tsconfig.json` path mappings that only point at declaration files. A types-only mapping such as `"topbar": ["./types/topbar.d.ts"]` became a bundler alias and bundled the `.d.ts` file in place of the package.
+
+## 0.19.4 - 2026-10-03
+
+### Compatibility
+
+- Require vize 0.16. Volt's use of vize is unchanged; 0.16 changes only `Vize.vapor_split/1`, which Volt doesn't call. PhoenixVapor needs vize 0.16 and Volt together.
+
+## 0.19.3 - 2026-10-01
+
+### Fixed
+
+- Leave `@oxc-project/runtime` helper imports to `OXC.bundle/2`, which provides them. Since 0.19.1, builds whose transformed code used a helper, such as lowered class fields in Svelte islands, failed with `{:not_found, "@oxc-project/runtime/..."}`.
+- Resolve application sources from their configured package scopes and `node_modules` before the directories above them. Since 0.19.1, a `node_modules` higher up could supply a second copy of a framework runtime. Packages still resolve their own dependencies from the nearest `node_modules` first.
+
+## 0.19.2 - 2026-09-30
+
+### Fixed
+
+- Accept diagnostic structs such as `Mix.Task.Compiler.Diagnostic` in `Volt.HMR.error/3`. Reading their fields with the Access syntax raised, so reporting compile errors crashed the caller.
+
+## 0.19.1 - 2026-09-30
+
+### Fixed
+
+- Resolve bare imports from the `node_modules` directories above the importer, nearest first, as Node does, before the configured `node_modules` and `resolve_dirs`. Dependencies nested under their dependent, pnpm layouts, and packages vendored beside `priv` sources now bundle instead of becoming undefined IIFE globals ([#44](https://github.com/elixir-volt/volt/issues/44)).
+- Fail the build with `{:error, {:not_found, specifier}}` for a bare import that resolves nowhere and is not listed in `:external`. It used to build and throw a `ReferenceError` at runtime.
+- Compile without warnings in apps that do not depend on the optional `lumis` package.
+
+## 0.19.0 - 2026-09-30
+
+### Breaking changes
+
+- Lint diagnostics are `OXC.Diagnostic` maps: severities are `:error` and `:warning`, and locations are 1-based `position` and `span` instead of byte offsets. Parse errors are diagnostics too, without a `rule`.
+- Lint `:plugins`, `:env`, and `:globals` take names as strings, as in an oxlint config file, such as `plugins: ["typescript", "react"]` and `env: ["browser"]`. Atom names raise an `ArgumentError`.
+- Custom lint rules report findings with AST `start` and `end` offsets instead of `span`.
+- `Volt.JS.Transforms.Imports.rewrite!/3` raises `OXC.Error` on parse errors.
+- HMR `error` messages carry the current `errors` as `Volt.Dev.Error` entries instead of a `path` and `reason`; an empty list hides the overlay.
+
+### Added
+
+- The error overlay shows each error's file, line, column, source frame, and hint.
+- The error overlay is a `<volt-error-overlay>` element rendered with lit-html into a Shadow DOM, so the app's styles cannot affect it.
+- Highlight the error overlay's source frame with the optional `lumis` dependency and its parser packages, such as `lumis_wasm_typescript`.
+- `Volt.HMR.error/3` takes a `:title` for the overlay heading, such as `"Render error"`. `Volt.HMR.clear_error/2` hides errors reported with `Volt.HMR.error/3`. Errors stay current until cleared, so browsers that connect later show them.
+- The dev server adds the HMR client to HTML pages the app renders.
+- `mix volt.priv.vendor` vendors npm packages for browser code under `priv`, keeping only the files the sources reach, for the Hex package rather than git. `Volt.Priv.bundle!/3` bundles a `priv` entry with them and vendors on first use in a git or path checkout. See "Browser code with npm packages" in the plugins guide.
+- The error overlay shows a diagnostic's stacktrace.
+
+### Changed
+
+- Require `oxc` 0.18.1, `vize` 0.15, `quickbeam` 0.11.2, and `json_codec` 0.3.
+
+### Fixed
+
+- Show the error overlay when a page loads with a module that fails to compile. The client previously loaded only through the failing module graph.
+- Hide the overlay once errors are fixed, and report Tailwind build failures, including at startup.
+- Reload the page after the HMR connection returns, since the server may have restarted.
+- Type-aware checks run the type-aware rules that lint categories such as `"correctness"` select, honoring individual rule settings and per-file overrides ([#40](https://github.com/elixir-volt/volt/issues/40)).
+- Type-aware checks extract single-file component scripts with the configured Volt plugins instead of the oxlint plugin names.
+
+## 0.18.1 - 2026-09-15
+
+### Added
+
+- Wire shared browser declarations into TypeScript configurations during installation. Create a configuration when absent, update ordinary JSON configurations without discarding existing settings, and provide manual guidance for JSONC and inherited or referenced projects.
+- Declare CSS side-effect imports and CSS modules in the shared browser declarations.
+
+## 0.18.0 - 2026-09-15
+
+### Breaking changes
+
+- Rename `Volt.JS.Helpers` to `Volt.JS.Discovery`, with `files/0,1` and `format_files/0` replacing `discover_files/0,1` and `discover_format_files/0`.
+
+### Added
+
+- Support root-relative, ordered lint overrides for rules, environments, and globals in both lint commands, including per-component TypeScript rule selection in type-aware checks ([#35](https://github.com/elixir-volt/volt/issues/35)).
+- Add `Volt.build/1` as the library API for complete frontend builds with one typed result and merged manifest for scripts, styles, chunks, and emitted assets.
+- Isolate Tailwind scanner and CSS state by profile and stylesheet root while sharing one supervised compiler runtime.
+- Allow Tailwind roots to configure their logical output name, development URL, and source globs.
+
+### Changed
+
+- Require QuickBEAM 0.11.1 or later in the 0.11 series for release-optimized, baseline-CPU precompiled runtimes and the Mint 1.10 security dependency floor.
+- Write one production manifest at the configured asset output root instead of separate JavaScript and Tailwind manifests.
+- Emit Tailwind development artifacts atomically and skip style HMR broadcasts when generated CSS is unchanged.
+
+### Fixed
+
+- Apply configured environments and globals in `mix volt.lint`, matching `mix volt.js.check`.
+- Allow JavaScript formatting and checks when the bundle format is configured as `:esm`, without treating the format atom as formatter options ([#36](https://github.com/elixir-volt/volt/pull/36), fixes [#34](https://github.com/elixir-volt/volt/issues/34)).
+- Handle filesystem watcher events for the watched root itself when normalizing macOS path aliases.
+- Apply Vue scoped styles without capturing component-module bindings such as `Object`.
+
+### Security
+
+- Require Igniter 0.8.4 or later to prevent terminal escape injection through package metadata in installer confirmation prompts (CVE-2026-82584).
+- Require Bandit 1.12.5 or later in the Phoenix examples to address HTTP/2 header validation and connection-window starvation (CVE-2026-75484, CVE-2026-74836).
+- Update Phoenix example locks to patched Phoenix and LiveView releases for channel-join and long-poll denial of service, presence-client crashes, link scheme validation, and redirect validation.
+
+## 0.17.11 - 2026-09-04
+
+### Added
+
+- Add Vite-style watcher ignore patterns through `config :volt, :server`, `Volt.Watcher`, and `mix volt.dev`, with default exclusions for common generated and dependency directories.
+
+### Fixed
+
+- Normalize filesystem aliases before routing watcher events so macOS events retain root-relative HMR paths.
+
+- Generate filesystem-safe entry and module labels for virtual modules on Windows.
+- Keep entry and module labels unique when filesystem sanitization produces collisions.
+- Use platform-aware absolute paths for builder, test discovery, glob transforms, and Tailwind resolution.
+- Make type-aware lint test executables and development dependency installation portable across Unix and Windows.
+- Update GlobEx for Windows-rooted glob matching.
+- Update QuickBEAM, OXC, Vize, Oxide, npm_ex, and ZiglerPrecompiled to their Windows-enabled releases.
+- Update Bandit to resolve its fragmented WebSocket message denial-of-service advisory.
+- Install built-in Svelte, Solid, and Tailwind runtimes from package-owned npm_ex lockfiles, and include each lock digest in the named runtime signature.
+- Preserve private and corporate npm registry compatibility by resolving exact built-in runtime packages through the configured registry when a packaged lock policy is incompatible.
+
+## 0.17.10 - 2026-07-17
+
+### Added
+
+- Allow `Volt.NPM.install!/2` to consume package-owned npm_ex lockfiles for resolver-free deterministic installs.
+
+### Fixed
+
+- Preserve nested dependency versions when generating isolated runtime lockfiles.
+
+## 0.17.9 - 2026-07-17
+
+### Added
+
+- Allow `Volt.Test.ExUnit.install/1` to execute large suites once per file with `granularity: :file`.
+
+## 0.17.8 - 2026-07-17
+
+### Improved
+
+- Rewrite production import labels from compact OXC parser events, avoiding full ESTree serialization for every compiled module.
+
+## 0.17.7 - 2026-07-16
+
+### Improved
+
+- Render splice-only private templates through OXC's native pipeline to avoid repeated ESTree serialization for large generated entries.
+
+## 0.17.6 - 2026-07-16
+
+### Fixed
+
+- Describe production build results with their strict `Volt.Builder.Result`, `ManifestEntry`, and `OutputFile` struct types.
+
+## 0.17.5 - 2026-07-13
+
+### Added
+
+- Pass configured Oxlint environments to OXC linting.
+
+## 0.17.4 - 2026-07-13
+
+### Added
+
+- Allow formatter and linter file discovery to override build `:root`, `:sources`, and `:ignore` independently.
+
+## 0.17.3 - 2026-07-13
+
+### Added
+
+- `Volt.Builder` accepts importer-scoped package directories through `:package_scopes`.
+- `Volt.NPM.install!/2` exposes isolated, npm_ex-backed package acquisition for frameworks and plugins.
+- `Volt.Priv.render!/4` applies literal bindings and AST splices while preserving TypeScript for a subsequent Volt build.
+
+### Fixed
+
+- Preserve importer package scopes while resolving transitive package imports.
+- Invalidate cached `Volt.Priv` templates and compiled modules when their source changes.
+- Type-check the private test-entry splice placeholder without changing rendered output.
+
+### Changed
+
+- Require Elixir 1.18 and Erlang/OTP 27, and verify those minimum versions in CI.
+
+## 0.17.2 - 2026-07-13
+
+### Added
+
+- `Volt.Priv.js!/4` accepts AST-backed statement, property, and array-element splices for private JavaScript and TypeScript templates.
+
+### Changed
+
+- Generate configured JavaScript test imports from a private TypeScript template instead of concatenating virtual-entry source.
 
 ## 0.17.1 - 2026-07-13
 
diff --git a/README.md b/README.md
index 094f7be..10b1b3e 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ mix igniter.install volt
 mix phx.server
 ```
 
-The installer configures everything. No binaries to download, no extra processes to manage.
+The installer configures everything. No binaries to download, no extra processes to manage. Volt requires Elixir 1.18 or later and Erlang/OTP 27 or later.
 
 ## Why Volt
 
@@ -31,7 +31,7 @@ Or add the dep manually:
 
 ```elixir
 def deps do
-  [{:volt, "~> 0.16"}]
+  [{:volt, "~> 0.23"}]
 end
 ```
 
@@ -88,13 +88,11 @@ The `Volt.DevServer` Plug starts its supervised file watcher on the first develo
 ```
 $ mix volt.build
 
-Building Tailwind CSS...
-  app-1a2b3c4d.css  23.9 KB
-Built Tailwind in 43ms
-Building "assets/js/app.ts"...
+Building ["assets/js/app.ts"]...
   app-5e6f7a8b.js  128.4 KB  (gzip: 38.2 KB)
+  app-1a2b3c4d.css  23.9 KB
   manifest.json  2 entries
-Built in 15ms
+Built in 58ms
 ```
 
 Tree-shaking, minification, code splitting, configurable env prefixes and asset URL prefixes, source maps, content-hashed JavaScript/CSS/assets, and manifest output. `Volt.Preload.tags/2` can generate modulepreload tags from the manifest, and the build is ready for `mix phx.digest`.
@@ -111,7 +109,11 @@ JS/TS formatting, linting, and testing run inside the BEAM. `mix format` handles
 
 ```elixir
 # .formatter.exs
-[plugins: [Volt.Formatter], inputs: ["assets/**/*.{js,ts,jsx,tsx}"]]
+[
+  plugins: [Volt.Formatter],
+  inputs: ["assets/**/*.{js,ts,jsx,tsx}"],
+  volt: [semi: false, single_quote: true]
+]
 ```
 
 ```bash
diff --git a/config/config.exs b/config/config.exs
index 98a050e..f97b032 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -1,15 +1,7 @@
 import Config
 
-config :volt, :format,
-  trailing_comma: :none,
-  tab_width: 2,
-  semi: false,
-  single_quote: true,
-  print_width: 100,
-  arrow_parens: :always
-
 config :volt, :lint,
-  plugins: [:typescript, :import, :unicorn],
+  plugins: ["typescript", "import", "unicorn"],
   rules: %{
     "no-unused-expressions" => :allow,
     "no-unused-vars" => :warn,
diff --git a/examples/react/.formatter.exs b/examples/react/.formatter.exs
index a0877aa..daa575d 100644
--- a/examples/react/.formatter.exs
+++ b/examples/react/.formatter.exs
@@ -5,5 +5,6 @@
     "*.{heex,ex,exs}",
     "{config,lib,test}/**/*.{heex,ex,exs}",
     "assets/**/*.{js,ts,jsx,tsx}"
-  ]
+  ],
+  volt: [semi: false, single_quote: true]
 ]
diff --git a/examples/react/config/config.exs b/examples/react/config/config.exs
index 7284372..e8fd363 100644
--- a/examples/react/config/config.exs
+++ b/examples/react/config/config.exs
@@ -23,7 +23,6 @@ config :volt,
   sources: ["**/*.{js,ts,jsx,tsx}"],
   target: :es2020,
   minify: false,
-  hash: false,
   resolve_dirs: ["node_modules", "deps"],
   tailwind: [
     css: "assets/css/app.css",
@@ -34,12 +33,8 @@ config :volt,
   ],
   import_source: "react"
 
-config :volt, :format,
-  semi: false,
-  single_quote: true
-
 config :volt, :lint,
-  plugins: [:typescript, :react],
+  plugins: ["typescript", "react"],
   tsgolint: System.find_executable("tsgolint"),
   rules: %{
     "correctness" => :deny,
diff --git a/examples/react/lib/react_example_web/components/layouts/root.html.heex b/examples/react/lib/react_example_web/components/layouts/root.html.heex
index bc3c5f4..e059290 100644
--- a/examples/react/lib/react_example_web/components/layouts/root.html.heex
+++ b/examples/react/lib/react_example_web/components/layouts/root.html.heex
@@ -5,7 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <meta name="csrf-token" content={get_csrf_token()} />
     <.live_title default="Volt React Example">Volt React Example</.live_title>
-    <link phx-track-static rel="stylesheet" href={~p"/assets/css/app.css"} />
+    <link phx-track-static rel="stylesheet" href={Volt.static_path(ReactExampleWeb.Endpoint, "/assets/css/app.css")} />
     <script defer phx-track-static type="module" src={Volt.entry_path(ReactExampleWeb.Endpoint)}></script>
   </head>
   <body>
diff --git a/examples/react/mix.exs b/examples/react/mix.exs
index 28d06b2..b2afdf7 100644
--- a/examples/react/mix.exs
+++ b/examples/react/mix.exs
@@ -35,7 +35,7 @@ defmodule ReactExample.MixProject do
       {:telemetry_poller, "~> 1.0"},
       {:jason, "~> 1.2"},
       {:dns_cluster, "~> 0.2.0"},
-      {:bandit, "~> 1.5"},
+      {:bandit, ">= 1.12.5 and < 2.0.0"},
       {:volt, path: "../..", override: true}
     ]
   end
@@ -43,8 +43,8 @@ defmodule ReactExample.MixProject do
   defp aliases do
     [
       setup: ["deps.get", "npm.install", "assets.build"],
-      "assets.build": ["volt.build --tailwind --no-hash --no-minify"],
-      "assets.deploy": ["volt.build --tailwind --no-hash", "phx.digest"],
+      "assets.build": ["volt.build --tailwind --no-minify"],
+      "assets.deploy": ["volt.build --tailwind", "phx.digest"],
       "assets.check": ["volt.js.check"],
       "assets.check.type_aware": ["volt.js.check --type-aware --type-check"],
       precommit: ["compile --warnings-as-errors", "format", "test"]
diff --git a/examples/react/mix.lock b/examples/react/mix.lock
index e37aeb5..1e04617 100644
--- a/examples/react/mix.lock
+++ b/examples/react/mix.lock
@@ -1,42 +1,45 @@
 %{
-  "bandit": {:hex, :bandit, "1.10.4", "02b9734c67c5916a008e7eb7e2ba68aaea6f8177094a5f8d95f1fb99069aac17", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.0", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "a5faf501042ac1f31d736d9d4a813b3db4ef812e634583b6a457b0928798a51d"},
-  "castore": {:hex, :castore, "1.0.19", "6903cabdfd9d1af46454126e7c8385186659dd33ecfb74a885cae52221ad6109", [:mix], [], "hexpm", "3669e6cab13f54c2df26b3e6833745d647f35b6e30d8ddd5975df0d5c842ca98"},
+  "bandit": {:hex, :bandit, "1.12.5", "af205a8e550f304caae09a97d29fd3c79a7f337526ea7cd772d2ff11d2f7c800", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.5", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "c5684ca062fa407cac115aec3256383f3e2ec9fdced7904d59cf5a7bb7ed6181"},
+  "castore": {:hex, :castore, "1.0.21", "0a0e8330dc267a40a3b7ad86d39302764bb71758172904e6a59d5ad6443ce307", [:mix], [], "hexpm", "e42e22723e25dbd46876d056a03f685513d6e98f6b5e555dc551321decd76c5c"},
   "dns_cluster": {:hex, :dns_cluster, "0.2.0", "aa8eb46e3bd0326bd67b84790c561733b25c5ba2fe3c7e36f28e88f384ebcb33", [:mix], [], "hexpm", "ba6f1893411c69c01b9e8e8f772062535a4cf70f3f35bcc964a324078d8c8240"},
   "dotenvy": {:hex, :dotenvy, "1.1.1", "00e318f3c51de9fafc4b48598447e386f19204dc18ca69886905bb8f8b08b667", [:mix], [], "hexpm", "c8269471b5701e9e56dc86509c1199ded2b33dce088c3471afcfef7839766d8e"},
   "file_system": {:hex, :file_system, "1.1.1", "31864f4685b0148f25bd3fbef2b1228457c0c89024ad67f7a81a3ffbc0bbad3a", [:mix], [], "hexpm", "7a15ff97dfe526aeefb090a7a9d3d03aa907e100e262a0f8f7746b78f8f87a5d"},
-  "finch": {:hex, :finch, "0.22.0", "5c48fa6f9706a78eb9036cacb67b8b996b4e66d111c543f4c29bb0f879a6806b", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b94e83c47780fc6813f746a1f1a34ee65cda42da4c5ea26a68f0acc4498e23dc"},
+  "finch": {:hex, :finch, "0.23.0", "e3f9287ac25a8832f848b144c2b57346aac65b205e2e0629a52adfe6507fd837", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "80e58d3f936f57e3fdf404f83a3642897ae6d9fb642934e46da4d8fe761b99d5"},
   "floki": {:hex, :floki, "0.38.1", "f002ccac94b3bcb21d40d9b34cc2cc9fd88a8311879120330075b5dde657ebee", [:mix], [], "hexpm", "e744bf0db7ee34b2c8b62767f04071107af0516a81144b9a2f73fe0494200e5b"},
-  "glob_ex": {:hex, :glob_ex, "0.1.11", "cb50d3f1ef53f6ca04d6252c7fde09fd7a1cf63387714fe96f340a1349e62c93", [:mix], [], "hexpm", "342729363056e3145e61766b416769984c329e4378f1d558b63e341020525de4"},
-  "hex_solver": {:hex, :hex_solver, "0.2.3", "0d2ee20fbceb251d573f03ef34852e325529c2874ab66d1b576384021318996c", [:mix], [], "hexpm", "9daeae2ea6b8ad3dc7f51a10484f6bc1d0f705c31063383830a7167ab93b887b"},
-  "hpax": {:hex, :hpax, "1.0.3", "ed67ef51ad4df91e75cc6a1494f851850c0bd98ebc0be6e81b026e765ee535aa", [:mix], [], "hexpm", "8eab6e1cfa8d5918c2ce4ba43588e894af35dbd8e91e6e55c817bca5847df34a"},
+  "glob_ex": {:hex, :glob_ex, "0.1.12", "7b2d9369c20e2697efcfd185d13d6e84c94cd3bfd2730fbde613141c2e015c00", [:mix], [], "hexpm", "2e2fac83f113514434c7eaf267b4c38af2f91766f1cab2c5db7053b7fc1ee0bb"},
+  "hex_solver": {:hex, :hex_solver, "0.3.0", "81e7659ad6caba1f856d89fc7ca52f88e8eb4f801deedcdce215f9006d706d1d", [:mix], [], "hexpm", "8a04c8ef0df25ca1f5e4d7d5f32833fac569f5c6442f05e216ee33615593e64d"},
+  "hpax": {:hex, :hpax, "1.0.4", "777de5d433b0fbdc7c418159c8055910faa8047ffdb3d6b31098d2a46cd7685c", [:mix], [], "hexpm", "afc7cb142ebcc2d01ce7816190b98ce5dd49e799111b24249f3443d730f377ca"},
   "jason": {:hex, :jason, "1.4.5", "2e3a008590b0b8d7388c20293e9dcc9cf3e5d642fd2a114e4cbbb52e595d940a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b0c823996102bcd0239b3c2444eb00409b72f6a140c1950bc8b457d836b30684"},
+  "json_codec": {:hex, :json_codec, "0.2.5", "4463d9db729ba994c356a0598b9a88ec0956a77e7ab778318d128b43db665faa", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:json_spec, "~> 1.2", [hex: :json_spec, repo: "hexpm", optional: false]}], "hexpm", "b32f189249cda0954a5fb6f4aab720444b5f3f81272869ce90098eea2418d465"},
+  "json_spec": {:hex, :json_spec, "1.2.0", "c67f73cdc4166e955b2f1095d3f44dd78c197337038f1a5301fb526b6c87ab04", [:mix], [], "hexpm", "3639961babad7d6bc45f3a2d96a49c18ec70614761bb84ce58b64e9fad9354de"},
   "mime": {:hex, :mime, "2.0.7", "b8d739037be7cd402aee1ba0306edfdef982687ee7e9859bee6198c1e7e2f128", [:mix], [], "hexpm", "6171188e399ee16023ffc5b76ce445eb6d9672e2e241d2df6050f3c771e80ccd"},
-  "mint": {:hex, :mint, "1.8.0", "b964eaf4416f2dee2ba88968d52239fca5621b0402b9c95f55a08eb9d74803e9", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "f3c572c11355eccf00f22275e9b42463bc17bd28db13be1e28f8e0bb4adbc849"},
-  "mint_web_socket": {:hex, :mint_web_socket, "1.0.5", "60354efeb49b1eccf95dfb75f55b08d692e211970fe735a5eb3188b328be2a90", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "04b35663448fc758f3356cce4d6ac067ca418bbafe6972a3805df984b5f12e61"},
+  "mint": {:hex, :mint, "1.10.0", "85af3353bfc504f5bdfe494bd92b8490f87a306dc659ee1ad0af435107e898dc", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "8b16fb72aaa7531d206a1f05e4cc85509ba531ccec7a17a22736c9c95cbb24d1"},
+  "mint_web_socket": {:hex, :mint_web_socket, "1.0.6", "5ffcf350df5b90f2d7a04adf877165228804993714592512374218d4679e325a", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "0c360e9012413f1c115a63532601eb5d63731aab7010949178769760686c1698"},
   "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.2", "8efba0122db06df95bfaa78f791344a89352ba04baedd3849593bfce4d0dc1c6", [:mix], [], "hexpm", "4b21398942dda052b403bbe1da991ccd03a053668d147d53fb8c4e0efe09c973"},
   "nimble_pool": {:hex, :nimble_pool, "1.1.0", "bf9c29fbdcba3564a8b800d1eeb5a3c58f36e1e11d7b7fb2e084a643f645f06b", [:mix], [], "hexpm", "af2e4e6b34197db81f7aad230c1118eac993acc0dae6bc83bac0126d4ae0813a"},
-  "npm": {:hex, :npm, "0.7.4", "a8cc2e760a30789e6b590257cfae9384fd1de470dab8ef62a7b35859587f34b7", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "ee265d380c19dbb9d1bba50458e1938711569a195423e6cfbf9ef7c3b8d7658a"},
+  "npm": {:hex, :npm, "0.7.6", "de8ca3dd26a40fac7ab8a17680088b8d55bab0e0294be9770b029c276361482f", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "e0a1ce77e3e49ec108e095aba133bd315e86da298dba26b142a105972141d9ef"},
   "npm_semver": {:hex, :npm_semver, "0.1.0", "3ab2c2a151d8c87c364209b2ca1a4fd2ab98507ed61afbd1ea12c1826e67200a", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "77afbc4c523c19a572325190bc4c968ec027e1c6ef8538bcddacf835966072fa"},
-  "oxc": {:hex, :oxc, "0.15.1", "d4b1770f26cd80b84ac592a54db38c50af92c98ce480be2ae1badbc0eccd614e", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "1008f80d04b961f5f262a0aec99781f3a73e5c4c7fc969f4336ca96f653c7d58"},
-  "oxide_ex": {:hex, :oxide_ex, "0.2.1", "ff0e1c03f58c151ca87e3b11847801a751853894fd926910f459ef5918cc655a", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "25bebc0d30362dead560e815a1380c266d018924a71a548ea2b1582f8dcd77bb"},
-  "phoenix": {:hex, :phoenix, "1.8.5", "919db335247e6d4891764dc3063415b0d2457641c5f9b3751b5df03d8e20bbcf", [:mix], [{:bandit, "~> 1.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.7", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5.3", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "83b2bb125127e02e9f475c8e3e92736325b5b01b0b9b05407bcb4083b7a32485"},
+  "oxc": {:hex, :oxc, "0.17.8", "e4c50ee0c0ce09107016b5153132b3d98421665355189b531c78ae4603047853", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "590fddfadbf843d6ab94e0f04a0e769a38358a23140728095da476c8c81f4df1"},
+  "oxide_ex": {:hex, :oxide_ex, "0.2.2", "063e0d2899e81632b7efc7849eb1dd89a7a623290a075c446b43bef14cf5795e", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "577a2fbd97c46904a31143bb700cdb374105085cfd1f7605416bb6c012cb7f60"},
+  "phoenix": {:hex, :phoenix, "1.8.14", "9279cbbcd755ac8d5f42d206915e7df13b9ab49096b98114f1c99ff908e5b42e", [:mix], [{:bandit, "~> 1.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.7", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 2.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "2782ff375824b2b5e41561fbae4764ee7b875af6898483bca49f24a9d1e37816"},
   "phoenix_html": {:hex, :phoenix_html, "4.3.0", "d3577a5df4b6954cd7890c84d955c470b5310bb49647f0a114a6eeecc850f7ad", [:mix], [], "hexpm", "3eaa290a78bab0f075f791a46a981bbe769d94bc776869f4f3063a14f30497ad"},
   "phoenix_live_reload": {:hex, :phoenix_live_reload, "1.6.2", "b18b0773a1ba77f28c52decbb0f10fd1ac4d3ae5b8632399bbf6986e3b665f62", [:mix], [{:file_system, "~> 0.2.10 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:phoenix, "~> 1.4", [hex: :phoenix, repo: "hexpm", optional: false]}], "hexpm", "d1f89c18114c50d394721365ffb428cce24f1c13de0467ffa773e2ff4a30d5b9"},
-  "phoenix_live_view": {:hex, :phoenix_live_view, "1.1.28", "8a8e123d018025f756605a2fb02a4854f0d3cd7b207f710fef1fd5d9d72d0254", [:mix], [{:igniter, ">= 0.6.16 and < 1.0.0-0", [hex: :igniter, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:lazy_html, "~> 0.1.0", [hex: :lazy_html, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0-rc", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "24faad535b65089642c3a7d84088109dc58f49c1f1c5a978659855d643466353"},
-  "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.2.0", "ff3a5616e1bed6804de7773b92cbccfc0b0f473faf1f63d7daf1206c7aeaaa6f", [:mix], [], "hexpm", "adc313a5bf7136039f63cfd9668fde73bba0765e0614cba80c06ac9460ff3e96"},
+  "phoenix_live_view": {:hex, :phoenix_live_view, "1.1.33", "8350c8bebabfa318c9afb0970eacced9174cd72603c9be2240e99d550fcc2eed", [:mix], [{:igniter, ">= 0.6.16 and < 1.0.0-0", [hex: :igniter, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:lazy_html, "~> 0.1.0", [hex: :lazy_html, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0-rc", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "2030f7987f641a269634e021bcde9373e5dea993f9373e628a44da86b2330b6c"},
+  "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.3.0", "03916bfbc31a5121945b3cfffe5aec647a5c97fe1dc172a319b94428562359c9", [:mix], [], "hexpm", "eec7be6e9cf02e2551d389b558402d6c637cd3973796326e7ba4bb03c6b2e91d"},
   "phoenix_template": {:hex, :phoenix_template, "1.0.4", "e2092c132f3b5e5b2d49c96695342eb36d0ed514c5b252a77048d5969330d639", [:mix], [{:phoenix_html, "~> 2.14.2 or ~> 3.0 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: true]}], "hexpm", "2c0c81f0e5c6753faf5cca2f229c9709919aba34fab866d3bc05060c9c444206"},
-  "plug": {:hex, :plug, "1.19.2", "e4950525b22c6789dfb38a3f95d47171ba159da3fc5a33be9643b43d5e8adb98", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b6fce20a56af5e60fa5dfecf3f907bb98ec981be43c79a3809a499bc3d133de0"},
-  "plug_crypto": {:hex, :plug_crypto, "2.1.1", "19bda8184399cb24afa10be734f84a16ea0a2bc65054e23a62bb10f06bc89491", [:mix], [], "hexpm", "6470bce6ffe41c8bd497612ffde1a7e4af67f36a15eea5f921af71cf3e11247c"},
-  "quickbeam": {:hex, :quickbeam, "0.10.15", "8622e090ba8476b4a7c008ddb75c741e770f45e64f9fc30c43b02694213a8605", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.4", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.15.0", [hex: :oxc, repo: "hexpm", optional: false]}, {:zigler, "~> 0.15.2", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.4", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "2da3750f1e99ae1d97b6e99a2b8ea86ba48c49c568d8f711d65d342430dcfb86"},
-  "req": {:hex, :req, "0.5.18", "48e6431cb4135e8a7815e745177485369a9b4a9924d5fe68ca00eb09ceaed1ef", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.21.0 or ~> 0.22.0", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "fa03812c440a9754bf34355e0c5d4f3ed316458db62e3284b7a352ef8dc0b996"},
+  "plug": {:hex, :plug, "1.20.3", "56c480c633ec2ce10140e236e15233bf576e1d323887d7c96711bd02ab5160db", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "be266aee1b8536ef6409d58cf39a3121319f0ec47cfa1b24024485aa0e76ad76"},
+  "plug_crypto": {:hex, :plug_crypto, "2.2.0", "144014737daaf485407f5ed77daeaad74d651b216a28c87543f8cc7043f8efc8", [:mix], [], "hexpm", "83a95744ab1c75876542b6fab135fcc176280e0f301a111c1f757fddcec95d2c"},
+  "quickbeam": {:hex, :quickbeam, "0.11.1", "55e7700b2a16c8df246402f8400908222e906f3b463af4ac8706f748d83b66db", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:mint, "~> 1.10", [hex: :mint, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.6", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.17.8", [hex: :oxc, repo: "hexpm", optional: false]}, {:varint, "~> 1.6", [hex: :varint, repo: "hexpm", optional: false]}, {:zigler, "~> 0.16.0", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.6", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "6c0240b9d016bbc174319ef004e81f2893ae2e77939d6b9b87c5542b344d0b87"},
+  "req": {:hex, :req, "0.7.4", "23e9ffec17de032a46a4b15ed65c09793893bf4a7c680f4bbf6227fce6bdf74d", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:finch, "~> 0.21", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "4b192d63253e8dcc6221ef992ea9ebef7d3555166e8423aa5b553e86bc3c69a2"},
   "rustler_precompiled": {:hex, :rustler_precompiled, "0.9.0", "3a052eda09f3d2436364645cc1f13279cf95db310eb0c17b0d8f25484b233aa0", [:mix], [{:rustler, "~> 0.23", [hex: :rustler, repo: "hexpm", optional: true]}], "hexpm", "471d97315bd3bf7b64623418b3693eedd8e47de3d1cb79a0ac8f9da7d770d94c"},
   "telemetry": {:hex, :telemetry, "1.4.2", "a0cb522801dffb1c49fe6e30561badffc7b6d0e180db1300df759faa22062855", [:rebar3], [], "hexpm", "928f6495066506077862c0d1646609eed891a4326bee3126ba54b60af61febb1"},
   "telemetry_metrics": {:hex, :telemetry_metrics, "1.1.0", "5bd5f3b5637e0abea0426b947e3ce5dd304f8b3bc6617039e2b5a008adc02f8f", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "e7b79e8ddfde70adb6db8a6623d1778ec66401f366e9a8f5dd0955c56bc8ce67"},
   "telemetry_poller": {:hex, :telemetry_poller, "1.3.0", "d5c46420126b5ac2d72bc6580fb4f537d35e851cc0f8dbd571acf6d6e10f5ec7", [:rebar3], [{:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "51f18bed7128544a50f75897db9974436ea9bfba560420b646af27a9a9b35211"},
-  "thousand_island": {:hex, :thousand_island, "1.4.3", "2158209580f633be38d43ec4e3ce0a01079592b9657afff9080d5d8ca149a3af", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "6e4ce09b0fd761a58594d02814d40f77daff460c48a7354a15ab353bb998ea0b"},
-  "vize": {:hex, :vize, "0.11.1", "eda811711b1663e548936b44ede72eac9bad1efdc1ff24be7ae86ea3b03541d2", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "9d53506c28c8c2a1947322d23fcb95c20e8c4d9ddb2e33b10c794e497ee55c5a"},
+  "thousand_island": {:hex, :thousand_island, "1.5.0", "f50a213cac97262b6d5ebb85745aa2c00fec1413191e6e66834788d45425cecb", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "708923d40523e43cf99041ab37a0d4b0ec426ac6438fa3716ab23d919eaeb412"},
+  "varint": {:hex, :varint, "1.6.0", "7bced828599b2eb84491a9f067f8a5a67fc35a946d3b7582278083c7fd434b00", [:mix], [], "hexpm", "2b4f4a20650aeebe993a70b03bb99571bcbddc27c361322c28b586d8a772ce4e"},
+  "vize": {:hex, :vize, "0.14.2", "4baf40c18e00963ce802c03ebb664feaccd8558d7ec62aa43fb07ad8485d0208", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "8336744616bc27ce4edc7448cda6f0b8a481cbec9035d3c4d6bf3229be91386d"},
   "websock": {:hex, :websock, "0.5.3", "2f69a6ebe810328555b6fe5c831a851f485e303a7c8ce6c5f675abeb20ebdadc", [:mix], [], "hexpm", "6105453d7fac22c712ad66fab1d45abdf049868f253cf719b625151460b8b453"},
-  "websock_adapter": {:hex, :websock_adapter, "0.5.9", "43dc3ba6d89ef5dec5b1d0a39698436a1e856d000d84bf31a3149862b01a287f", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "5534d5c9adad3c18a0f58a9371220d75a803bf0b9a3d87e6fe072faaeed76a08"},
-  "zigler_precompiled": {:hex, :zigler_precompiled, "0.1.4", "20a166584b94d860a983ef39c93cb0a9ce40c95c48555fc3cb6532c405558410", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:zigler, "~> 0.13", [hex: :zigler, repo: "hexpm", optional: true]}], "hexpm", "9cd6998a8ddf2f03ded1b6ebc9acb9bfa5e23b614f047583c76c01bf66c4640e"},
+  "websock_adapter": {:hex, :websock_adapter, "0.6.0", "73db5ab8aaefd1a876a97ce3e6afc96562625de69ef17a4e04426e034849d0b8", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "50021a85bce8f203b086705d9e0c5415e2c7eb05d319111b0428fe71f9934617"},
+  "zigler_precompiled": {:hex, :zigler_precompiled, "0.1.6", "1c5c889ff30164eb340e599ae987b6c51c3ba0654117ec7a68a6b83d4df39310", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:zigler, "~> 0.13", [hex: :zigler, repo: "hexpm", optional: true]}], "hexpm", "5754d342533b2fb8e767c0ef216ee13c928e17f317cac7d6a01a0972ba68ce4a"},
 }
diff --git a/examples/solid/.formatter.exs b/examples/solid/.formatter.exs
index a0877aa..daa575d 100644
--- a/examples/solid/.formatter.exs
+++ b/examples/solid/.formatter.exs
@@ -5,5 +5,6 @@
     "*.{heex,ex,exs}",
     "{config,lib,test}/**/*.{heex,ex,exs}",
     "assets/**/*.{js,ts,jsx,tsx}"
-  ]
+  ],
+  volt: [semi: false, single_quote: true]
 ]
diff --git a/examples/solid/config/config.exs b/examples/solid/config/config.exs
index 6ef3959..af08475 100644
--- a/examples/solid/config/config.exs
+++ b/examples/solid/config/config.exs
@@ -23,7 +23,6 @@ config :volt,
   sources: ["**/*.{js,ts,jsx,tsx}"],
   target: :es2020,
   minify: false,
-  hash: false,
   resolve_dirs: ["node_modules", "deps"],
   plugins: [Volt.Plugin.Solid],
   tailwind: [
@@ -34,12 +33,8 @@ config :volt,
     ]
   ]
 
-config :volt, :format,
-  semi: false,
-  single_quote: true
-
 config :volt, :lint,
-  plugins: [:typescript],
+  plugins: ["typescript"],
   tsgolint: System.find_executable("tsgolint"),
   rules: %{
     "correctness" => :deny,
diff --git a/examples/solid/lib/solid_example_web/components/layouts/root.html.heex b/examples/solid/lib/solid_example_web/components/layouts/root.html.heex
index ec520e6..f08df0b 100644
--- a/examples/solid/lib/solid_example_web/components/layouts/root.html.heex
+++ b/examples/solid/lib/solid_example_web/components/layouts/root.html.heex
@@ -5,7 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <meta name="csrf-token" content={get_csrf_token()} />
     <.live_title default="Volt Solid Example">Volt Solid Example</.live_title>
-    <link phx-track-static rel="stylesheet" href={~p"/assets/css/app.css"} />
+    <link phx-track-static rel="stylesheet" href={Volt.static_path(SolidExampleWeb.Endpoint, "/assets/css/app.css")} />
     <script defer phx-track-static type="module" src={Volt.entry_path(SolidExampleWeb.Endpoint)}></script>
   </head>
   <body>
diff --git a/examples/solid/mix.exs b/examples/solid/mix.exs
index 9c41f61..1ce7292 100644
--- a/examples/solid/mix.exs
+++ b/examples/solid/mix.exs
@@ -35,7 +35,7 @@ defmodule SolidExample.MixProject do
       {:telemetry_poller, "~> 1.0"},
       {:jason, "~> 1.2"},
       {:dns_cluster, "~> 0.2.0"},
-      {:bandit, "~> 1.5"},
+      {:bandit, ">= 1.12.5 and < 2.0.0"},
       {:volt, path: "../..", override: true}
     ]
   end
@@ -43,8 +43,8 @@ defmodule SolidExample.MixProject do
   defp aliases do
     [
       setup: ["deps.get", "npm.install", "assets.build"],
-      "assets.build": ["volt.build --tailwind --no-hash --no-minify"],
-      "assets.deploy": ["volt.build --tailwind --no-hash", "phx.digest"],
+      "assets.build": ["volt.build --tailwind --no-minify"],
+      "assets.deploy": ["volt.build --tailwind", "phx.digest"],
       "assets.check": ["volt.js.check"],
       "assets.check.type_aware": ["volt.js.check --type-aware --type-check"],
       precommit: ["compile --warnings-as-errors", "format", "test"]
diff --git a/examples/solid/mix.lock b/examples/solid/mix.lock
index e37aeb5..1e04617 100644
--- a/examples/solid/mix.lock
+++ b/examples/solid/mix.lock
@@ -1,42 +1,45 @@
 %{
-  "bandit": {:hex, :bandit, "1.10.4", "02b9734c67c5916a008e7eb7e2ba68aaea6f8177094a5f8d95f1fb99069aac17", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.0", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "a5faf501042ac1f31d736d9d4a813b3db4ef812e634583b6a457b0928798a51d"},
-  "castore": {:hex, :castore, "1.0.19", "6903cabdfd9d1af46454126e7c8385186659dd33ecfb74a885cae52221ad6109", [:mix], [], "hexpm", "3669e6cab13f54c2df26b3e6833745d647f35b6e30d8ddd5975df0d5c842ca98"},
+  "bandit": {:hex, :bandit, "1.12.5", "af205a8e550f304caae09a97d29fd3c79a7f337526ea7cd772d2ff11d2f7c800", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.5", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "c5684ca062fa407cac115aec3256383f3e2ec9fdced7904d59cf5a7bb7ed6181"},
+  "castore": {:hex, :castore, "1.0.21", "0a0e8330dc267a40a3b7ad86d39302764bb71758172904e6a59d5ad6443ce307", [:mix], [], "hexpm", "e42e22723e25dbd46876d056a03f685513d6e98f6b5e555dc551321decd76c5c"},
   "dns_cluster": {:hex, :dns_cluster, "0.2.0", "aa8eb46e3bd0326bd67b84790c561733b25c5ba2fe3c7e36f28e88f384ebcb33", [:mix], [], "hexpm", "ba6f1893411c69c01b9e8e8f772062535a4cf70f3f35bcc964a324078d8c8240"},
   "dotenvy": {:hex, :dotenvy, "1.1.1", "00e318f3c51de9fafc4b48598447e386f19204dc18ca69886905bb8f8b08b667", [:mix], [], "hexpm", "c8269471b5701e9e56dc86509c1199ded2b33dce088c3471afcfef7839766d8e"},
   "file_system": {:hex, :file_system, "1.1.1", "31864f4685b0148f25bd3fbef2b1228457c0c89024ad67f7a81a3ffbc0bbad3a", [:mix], [], "hexpm", "7a15ff97dfe526aeefb090a7a9d3d03aa907e100e262a0f8f7746b78f8f87a5d"},
-  "finch": {:hex, :finch, "0.22.0", "5c48fa6f9706a78eb9036cacb67b8b996b4e66d111c543f4c29bb0f879a6806b", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b94e83c47780fc6813f746a1f1a34ee65cda42da4c5ea26a68f0acc4498e23dc"},
+  "finch": {:hex, :finch, "0.23.0", "e3f9287ac25a8832f848b144c2b57346aac65b205e2e0629a52adfe6507fd837", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "80e58d3f936f57e3fdf404f83a3642897ae6d9fb642934e46da4d8fe761b99d5"},
   "floki": {:hex, :floki, "0.38.1", "f002ccac94b3bcb21d40d9b34cc2cc9fd88a8311879120330075b5dde657ebee", [:mix], [], "hexpm", "e744bf0db7ee34b2c8b62767f04071107af0516a81144b9a2f73fe0494200e5b"},
-  "glob_ex": {:hex, :glob_ex, "0.1.11", "cb50d3f1ef53f6ca04d6252c7fde09fd7a1cf63387714fe96f340a1349e62c93", [:mix], [], "hexpm", "342729363056e3145e61766b416769984c329e4378f1d558b63e341020525de4"},
-  "hex_solver": {:hex, :hex_solver, "0.2.3", "0d2ee20fbceb251d573f03ef34852e325529c2874ab66d1b576384021318996c", [:mix], [], "hexpm", "9daeae2ea6b8ad3dc7f51a10484f6bc1d0f705c31063383830a7167ab93b887b"},
-  "hpax": {:hex, :hpax, "1.0.3", "ed67ef51ad4df91e75cc6a1494f851850c0bd98ebc0be6e81b026e765ee535aa", [:mix], [], "hexpm", "8eab6e1cfa8d5918c2ce4ba43588e894af35dbd8e91e6e55c817bca5847df34a"},
+  "glob_ex": {:hex, :glob_ex, "0.1.12", "7b2d9369c20e2697efcfd185d13d6e84c94cd3bfd2730fbde613141c2e015c00", [:mix], [], "hexpm", "2e2fac83f113514434c7eaf267b4c38af2f91766f1cab2c5db7053b7fc1ee0bb"},
+  "hex_solver": {:hex, :hex_solver, "0.3.0", "81e7659ad6caba1f856d89fc7ca52f88e8eb4f801deedcdce215f9006d706d1d", [:mix], [], "hexpm", "8a04c8ef0df25ca1f5e4d7d5f32833fac569f5c6442f05e216ee33615593e64d"},
+  "hpax": {:hex, :hpax, "1.0.4", "777de5d433b0fbdc7c418159c8055910faa8047ffdb3d6b31098d2a46cd7685c", [:mix], [], "hexpm", "afc7cb142ebcc2d01ce7816190b98ce5dd49e799111b24249f3443d730f377ca"},
   "jason": {:hex, :jason, "1.4.5", "2e3a008590b0b8d7388c20293e9dcc9cf3e5d642fd2a114e4cbbb52e595d940a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b0c823996102bcd0239b3c2444eb00409b72f6a140c1950bc8b457d836b30684"},
+  "json_codec": {:hex, :json_codec, "0.2.5", "4463d9db729ba994c356a0598b9a88ec0956a77e7ab778318d128b43db665faa", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:json_spec, "~> 1.2", [hex: :json_spec, repo: "hexpm", optional: false]}], "hexpm", "b32f189249cda0954a5fb6f4aab720444b5f3f81272869ce90098eea2418d465"},
+  "json_spec": {:hex, :json_spec, "1.2.0", "c67f73cdc4166e955b2f1095d3f44dd78c197337038f1a5301fb526b6c87ab04", [:mix], [], "hexpm", "3639961babad7d6bc45f3a2d96a49c18ec70614761bb84ce58b64e9fad9354de"},
   "mime": {:hex, :mime, "2.0.7", "b8d739037be7cd402aee1ba0306edfdef982687ee7e9859bee6198c1e7e2f128", [:mix], [], "hexpm", "6171188e399ee16023ffc5b76ce445eb6d9672e2e241d2df6050f3c771e80ccd"},
-  "mint": {:hex, :mint, "1.8.0", "b964eaf4416f2dee2ba88968d52239fca5621b0402b9c95f55a08eb9d74803e9", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "f3c572c11355eccf00f22275e9b42463bc17bd28db13be1e28f8e0bb4adbc849"},
-  "mint_web_socket": {:hex, :mint_web_socket, "1.0.5", "60354efeb49b1eccf95dfb75f55b08d692e211970fe735a5eb3188b328be2a90", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "04b35663448fc758f3356cce4d6ac067ca418bbafe6972a3805df984b5f12e61"},
+  "mint": {:hex, :mint, "1.10.0", "85af3353bfc504f5bdfe494bd92b8490f87a306dc659ee1ad0af435107e898dc", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "8b16fb72aaa7531d206a1f05e4cc85509ba531ccec7a17a22736c9c95cbb24d1"},
+  "mint_web_socket": {:hex, :mint_web_socket, "1.0.6", "5ffcf350df5b90f2d7a04adf877165228804993714592512374218d4679e325a", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "0c360e9012413f1c115a63532601eb5d63731aab7010949178769760686c1698"},
   "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.2", "8efba0122db06df95bfaa78f791344a89352ba04baedd3849593bfce4d0dc1c6", [:mix], [], "hexpm", "4b21398942dda052b403bbe1da991ccd03a053668d147d53fb8c4e0efe09c973"},
   "nimble_pool": {:hex, :nimble_pool, "1.1.0", "bf9c29fbdcba3564a8b800d1eeb5a3c58f36e1e11d7b7fb2e084a643f645f06b", [:mix], [], "hexpm", "af2e4e6b34197db81f7aad230c1118eac993acc0dae6bc83bac0126d4ae0813a"},
-  "npm": {:hex, :npm, "0.7.4", "a8cc2e760a30789e6b590257cfae9384fd1de470dab8ef62a7b35859587f34b7", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "ee265d380c19dbb9d1bba50458e1938711569a195423e6cfbf9ef7c3b8d7658a"},
+  "npm": {:hex, :npm, "0.7.6", "de8ca3dd26a40fac7ab8a17680088b8d55bab0e0294be9770b029c276361482f", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "e0a1ce77e3e49ec108e095aba133bd315e86da298dba26b142a105972141d9ef"},
   "npm_semver": {:hex, :npm_semver, "0.1.0", "3ab2c2a151d8c87c364209b2ca1a4fd2ab98507ed61afbd1ea12c1826e67200a", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "77afbc4c523c19a572325190bc4c968ec027e1c6ef8538bcddacf835966072fa"},
-  "oxc": {:hex, :oxc, "0.15.1", "d4b1770f26cd80b84ac592a54db38c50af92c98ce480be2ae1badbc0eccd614e", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "1008f80d04b961f5f262a0aec99781f3a73e5c4c7fc969f4336ca96f653c7d58"},
-  "oxide_ex": {:hex, :oxide_ex, "0.2.1", "ff0e1c03f58c151ca87e3b11847801a751853894fd926910f459ef5918cc655a", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "25bebc0d30362dead560e815a1380c266d018924a71a548ea2b1582f8dcd77bb"},
-  "phoenix": {:hex, :phoenix, "1.8.5", "919db335247e6d4891764dc3063415b0d2457641c5f9b3751b5df03d8e20bbcf", [:mix], [{:bandit, "~> 1.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.7", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5.3", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "83b2bb125127e02e9f475c8e3e92736325b5b01b0b9b05407bcb4083b7a32485"},
+  "oxc": {:hex, :oxc, "0.17.8", "e4c50ee0c0ce09107016b5153132b3d98421665355189b531c78ae4603047853", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "590fddfadbf843d6ab94e0f04a0e769a38358a23140728095da476c8c81f4df1"},
+  "oxide_ex": {:hex, :oxide_ex, "0.2.2", "063e0d2899e81632b7efc7849eb1dd89a7a623290a075c446b43bef14cf5795e", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "577a2fbd97c46904a31143bb700cdb374105085cfd1f7605416bb6c012cb7f60"},
+  "phoenix": {:hex, :phoenix, "1.8.14", "9279cbbcd755ac8d5f42d206915e7df13b9ab49096b98114f1c99ff908e5b42e", [:mix], [{:bandit, "~> 1.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.7", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 2.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "2782ff375824b2b5e41561fbae4764ee7b875af6898483bca49f24a9d1e37816"},
   "phoenix_html": {:hex, :phoenix_html, "4.3.0", "d3577a5df4b6954cd7890c84d955c470b5310bb49647f0a114a6eeecc850f7ad", [:mix], [], "hexpm", "3eaa290a78bab0f075f791a46a981bbe769d94bc776869f4f3063a14f30497ad"},
   "phoenix_live_reload": {:hex, :phoenix_live_reload, "1.6.2", "b18b0773a1ba77f28c52decbb0f10fd1ac4d3ae5b8632399bbf6986e3b665f62", [:mix], [{:file_system, "~> 0.2.10 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:phoenix, "~> 1.4", [hex: :phoenix, repo: "hexpm", optional: false]}], "hexpm", "d1f89c18114c50d394721365ffb428cce24f1c13de0467ffa773e2ff4a30d5b9"},
-  "phoenix_live_view": {:hex, :phoenix_live_view, "1.1.28", "8a8e123d018025f756605a2fb02a4854f0d3cd7b207f710fef1fd5d9d72d0254", [:mix], [{:igniter, ">= 0.6.16 and < 1.0.0-0", [hex: :igniter, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:lazy_html, "~> 0.1.0", [hex: :lazy_html, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0-rc", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "24faad535b65089642c3a7d84088109dc58f49c1f1c5a978659855d643466353"},
-  "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.2.0", "ff3a5616e1bed6804de7773b92cbccfc0b0f473faf1f63d7daf1206c7aeaaa6f", [:mix], [], "hexpm", "adc313a5bf7136039f63cfd9668fde73bba0765e0614cba80c06ac9460ff3e96"},
+  "phoenix_live_view": {:hex, :phoenix_live_view, "1.1.33", "8350c8bebabfa318c9afb0970eacced9174cd72603c9be2240e99d550fcc2eed", [:mix], [{:igniter, ">= 0.6.16 and < 1.0.0-0", [hex: :igniter, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:lazy_html, "~> 0.1.0", [hex: :lazy_html, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0-rc", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "2030f7987f641a269634e021bcde9373e5dea993f9373e628a44da86b2330b6c"},
+  "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.3.0", "03916bfbc31a5121945b3cfffe5aec647a5c97fe1dc172a319b94428562359c9", [:mix], [], "hexpm", "eec7be6e9cf02e2551d389b558402d6c637cd3973796326e7ba4bb03c6b2e91d"},
   "phoenix_template": {:hex, :phoenix_template, "1.0.4", "e2092c132f3b5e5b2d49c96695342eb36d0ed514c5b252a77048d5969330d639", [:mix], [{:phoenix_html, "~> 2.14.2 or ~> 3.0 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: true]}], "hexpm", "2c0c81f0e5c6753faf5cca2f229c9709919aba34fab866d3bc05060c9c444206"},
-  "plug": {:hex, :plug, "1.19.2", "e4950525b22c6789dfb38a3f95d47171ba159da3fc5a33be9643b43d5e8adb98", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b6fce20a56af5e60fa5dfecf3f907bb98ec981be43c79a3809a499bc3d133de0"},
-  "plug_crypto": {:hex, :plug_crypto, "2.1.1", "19bda8184399cb24afa10be734f84a16ea0a2bc65054e23a62bb10f06bc89491", [:mix], [], "hexpm", "6470bce6ffe41c8bd497612ffde1a7e4af67f36a15eea5f921af71cf3e11247c"},
-  "quickbeam": {:hex, :quickbeam, "0.10.15", "8622e090ba8476b4a7c008ddb75c741e770f45e64f9fc30c43b02694213a8605", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.4", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.15.0", [hex: :oxc, repo: "hexpm", optional: false]}, {:zigler, "~> 0.15.2", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.4", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "2da3750f1e99ae1d97b6e99a2b8ea86ba48c49c568d8f711d65d342430dcfb86"},
-  "req": {:hex, :req, "0.5.18", "48e6431cb4135e8a7815e745177485369a9b4a9924d5fe68ca00eb09ceaed1ef", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.21.0 or ~> 0.22.0", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "fa03812c440a9754bf34355e0c5d4f3ed316458db62e3284b7a352ef8dc0b996"},
+  "plug": {:hex, :plug, "1.20.3", "56c480c633ec2ce10140e236e15233bf576e1d323887d7c96711bd02ab5160db", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "be266aee1b8536ef6409d58cf39a3121319f0ec47cfa1b24024485aa0e76ad76"},
+  "plug_crypto": {:hex, :plug_crypto, "2.2.0", "144014737daaf485407f5ed77daeaad74d651b216a28c87543f8cc7043f8efc8", [:mix], [], "hexpm", "83a95744ab1c75876542b6fab135fcc176280e0f301a111c1f757fddcec95d2c"},
+  "quickbeam": {:hex, :quickbeam, "0.11.1", "55e7700b2a16c8df246402f8400908222e906f3b463af4ac8706f748d83b66db", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:mint, "~> 1.10", [hex: :mint, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.6", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.17.8", [hex: :oxc, repo: "hexpm", optional: false]}, {:varint, "~> 1.6", [hex: :varint, repo: "hexpm", optional: false]}, {:zigler, "~> 0.16.0", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.6", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "6c0240b9d016bbc174319ef004e81f2893ae2e77939d6b9b87c5542b344d0b87"},
+  "req": {:hex, :req, "0.7.4", "23e9ffec17de032a46a4b15ed65c09793893bf4a7c680f4bbf6227fce6bdf74d", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:finch, "~> 0.21", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "4b192d63253e8dcc6221ef992ea9ebef7d3555166e8423aa5b553e86bc3c69a2"},
   "rustler_precompiled": {:hex, :rustler_precompiled, "0.9.0", "3a052eda09f3d2436364645cc1f13279cf95db310eb0c17b0d8f25484b233aa0", [:mix], [{:rustler, "~> 0.23", [hex: :rustler, repo: "hexpm", optional: true]}], "hexpm", "471d97315bd3bf7b64623418b3693eedd8e47de3d1cb79a0ac8f9da7d770d94c"},
   "telemetry": {:hex, :telemetry, "1.4.2", "a0cb522801dffb1c49fe6e30561badffc7b6d0e180db1300df759faa22062855", [:rebar3], [], "hexpm", "928f6495066506077862c0d1646609eed891a4326bee3126ba54b60af61febb1"},
   "telemetry_metrics": {:hex, :telemetry_metrics, "1.1.0", "5bd5f3b5637e0abea0426b947e3ce5dd304f8b3bc6617039e2b5a008adc02f8f", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "e7b79e8ddfde70adb6db8a6623d1778ec66401f366e9a8f5dd0955c56bc8ce67"},
   "telemetry_poller": {:hex, :telemetry_poller, "1.3.0", "d5c46420126b5ac2d72bc6580fb4f537d35e851cc0f8dbd571acf6d6e10f5ec7", [:rebar3], [{:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "51f18bed7128544a50f75897db9974436ea9bfba560420b646af27a9a9b35211"},
-  "thousand_island": {:hex, :thousand_island, "1.4.3", "2158209580f633be38d43ec4e3ce0a01079592b9657afff9080d5d8ca149a3af", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "6e4ce09b0fd761a58594d02814d40f77daff460c48a7354a15ab353bb998ea0b"},
-  "vize": {:hex, :vize, "0.11.1", "eda811711b1663e548936b44ede72eac9bad1efdc1ff24be7ae86ea3b03541d2", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "9d53506c28c8c2a1947322d23fcb95c20e8c4d9ddb2e33b10c794e497ee55c5a"},
+  "thousand_island": {:hex, :thousand_island, "1.5.0", "f50a213cac97262b6d5ebb85745aa2c00fec1413191e6e66834788d45425cecb", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "708923d40523e43cf99041ab37a0d4b0ec426ac6438fa3716ab23d919eaeb412"},
+  "varint": {:hex, :varint, "1.6.0", "7bced828599b2eb84491a9f067f8a5a67fc35a946d3b7582278083c7fd434b00", [:mix], [], "hexpm", "2b4f4a20650aeebe993a70b03bb99571bcbddc27c361322c28b586d8a772ce4e"},
+  "vize": {:hex, :vize, "0.14.2", "4baf40c18e00963ce802c03ebb664feaccd8558d7ec62aa43fb07ad8485d0208", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "8336744616bc27ce4edc7448cda6f0b8a481cbec9035d3c4d6bf3229be91386d"},
   "websock": {:hex, :websock, "0.5.3", "2f69a6ebe810328555b6fe5c831a851f485e303a7c8ce6c5f675abeb20ebdadc", [:mix], [], "hexpm", "6105453d7fac22c712ad66fab1d45abdf049868f253cf719b625151460b8b453"},
-  "websock_adapter": {:hex, :websock_adapter, "0.5.9", "43dc3ba6d89ef5dec5b1d0a39698436a1e856d000d84bf31a3149862b01a287f", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "5534d5c9adad3c18a0f58a9371220d75a803bf0b9a3d87e6fe072faaeed76a08"},
-  "zigler_precompiled": {:hex, :zigler_precompiled, "0.1.4", "20a166584b94d860a983ef39c93cb0a9ce40c95c48555fc3cb6532c405558410", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:zigler, "~> 0.13", [hex: :zigler, repo: "hexpm", optional: true]}], "hexpm", "9cd6998a8ddf2f03ded1b6ebc9acb9bfa5e23b614f047583c76c01bf66c4640e"},
+  "websock_adapter": {:hex, :websock_adapter, "0.6.0", "73db5ab8aaefd1a876a97ce3e6afc96562625de69ef17a4e04426e034849d0b8", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "50021a85bce8f203b086705d9e0c5415e2c7eb05d319111b0428fe71f9934617"},
+  "zigler_precompiled": {:hex, :zigler_precompiled, "0.1.6", "1c5c889ff30164eb340e599ae987b6c51c3ba0654117ec7a68a6b83d4df39310", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:zigler, "~> 0.13", [hex: :zigler, repo: "hexpm", optional: true]}], "hexpm", "5754d342533b2fb8e767c0ef216ee13c928e17f317cac7d6a01a0972ba68ce4a"},
 }
diff --git a/examples/svelte/.formatter.exs b/examples/svelte/.formatter.exs
index a0877aa..daa575d 100644
--- a/examples/svelte/.formatter.exs
+++ b/examples/svelte/.formatter.exs
@@ -5,5 +5,6 @@
     "*.{heex,ex,exs}",
     "{config,lib,test}/**/*.{heex,ex,exs}",
     "assets/**/*.{js,ts,jsx,tsx}"
-  ]
+  ],
+  volt: [semi: false, single_quote: true]
 ]
diff --git a/examples/svelte/config/config.exs b/examples/svelte/config/config.exs
index 8f9b141..5cea6b3 100644
--- a/examples/svelte/config/config.exs
+++ b/examples/svelte/config/config.exs
@@ -23,7 +23,6 @@ config :volt,
   sources: ["**/*.{js,ts,jsx,tsx,svelte}"],
   target: :es2022,
   minify: false,
-  hash: false,
   resolve_dirs: ["node_modules", "deps"],
   tailwind: [
     css: "assets/css/app.css",
@@ -33,12 +32,8 @@ config :volt,
     ]
   ]
 
-config :volt, :format,
-  semi: false,
-  single_quote: true
-
 config :volt, :lint,
-  plugins: [:typescript],
+  plugins: ["typescript"],
   tsgolint: System.find_executable("tsgolint"),
   rules: %{
     "correctness" => :deny,
diff --git a/examples/svelte/lib/svelte_example_web/components/layouts/root.html.heex b/examples/svelte/lib/svelte_example_web/components/layouts/root.html.heex
index b31db71..308d4b4 100644
--- a/examples/svelte/lib/svelte_example_web/components/layouts/root.html.heex
+++ b/examples/svelte/lib/svelte_example_web/components/layouts/root.html.heex
@@ -5,7 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <meta name="csrf-token" content={get_csrf_token()} />
     <.live_title default="Volt Svelte Example">Volt Svelte Example</.live_title>
-    <link phx-track-static rel="stylesheet" href={~p"/assets/css/app.css"} />
+    <link phx-track-static rel="stylesheet" href={Volt.static_path(SvelteExampleWeb.Endpoint, "/assets/css/app.css")} />
     <script defer phx-track-static type="module" src={Volt.entry_path(SvelteExampleWeb.Endpoint)}></script>
   </head>
   <body>
diff --git a/examples/svelte/mix.exs b/examples/svelte/mix.exs
index b401cdc..99412b2 100644
--- a/examples/svelte/mix.exs
+++ b/examples/svelte/mix.exs
@@ -35,7 +35,7 @@ defmodule SvelteExample.MixProject do
       {:telemetry_poller, "~> 1.0"},
       {:jason, "~> 1.2"},
       {:dns_cluster, "~> 0.2.0"},
-      {:bandit, "~> 1.5"},
+      {:bandit, ">= 1.12.5 and < 2.0.0"},
       {:volt, path: "../..", override: true}
     ]
   end
@@ -43,8 +43,8 @@ defmodule SvelteExample.MixProject do
   defp aliases do
     [
       setup: ["deps.get", "npm.install", "assets.build"],
-      "assets.build": ["volt.build --tailwind --no-hash --no-minify"],
-      "assets.deploy": ["volt.build --tailwind --no-hash", "phx.digest"],
+      "assets.build": ["volt.build --tailwind --no-minify"],
+      "assets.deploy": ["volt.build --tailwind", "phx.digest"],
       "assets.check": ["volt.js.check"],
       "assets.check.type_aware": ["volt.js.check --type-aware --type-check"],
       precommit: ["compile --warnings-as-errors", "format", "test"]
diff --git a/examples/svelte/mix.lock b/examples/svelte/mix.lock
index e37aeb5..1e04617 100644
--- a/examples/svelte/mix.lock
+++ b/examples/svelte/mix.lock
@@ -1,42 +1,45 @@
 %{
-  "bandit": {:hex, :bandit, "1.10.4", "02b9734c67c5916a008e7eb7e2ba68aaea6f8177094a5f8d95f1fb99069aac17", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.0", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "a5faf501042ac1f31d736d9d4a813b3db4ef812e634583b6a457b0928798a51d"},
-  "castore": {:hex, :castore, "1.0.19", "6903cabdfd9d1af46454126e7c8385186659dd33ecfb74a885cae52221ad6109", [:mix], [], "hexpm", "3669e6cab13f54c2df26b3e6833745d647f35b6e30d8ddd5975df0d5c842ca98"},
+  "bandit": {:hex, :bandit, "1.12.5", "af205a8e550f304caae09a97d29fd3c79a7f337526ea7cd772d2ff11d2f7c800", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.5", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "c5684ca062fa407cac115aec3256383f3e2ec9fdced7904d59cf5a7bb7ed6181"},
+  "castore": {:hex, :castore, "1.0.21", "0a0e8330dc267a40a3b7ad86d39302764bb71758172904e6a59d5ad6443ce307", [:mix], [], "hexpm", "e42e22723e25dbd46876d056a03f685513d6e98f6b5e555dc551321decd76c5c"},
   "dns_cluster": {:hex, :dns_cluster, "0.2.0", "aa8eb46e3bd0326bd67b84790c561733b25c5ba2fe3c7e36f28e88f384ebcb33", [:mix], [], "hexpm", "ba6f1893411c69c01b9e8e8f772062535a4cf70f3f35bcc964a324078d8c8240"},
   "dotenvy": {:hex, :dotenvy, "1.1.1", "00e318f3c51de9fafc4b48598447e386f19204dc18ca69886905bb8f8b08b667", [:mix], [], "hexpm", "c8269471b5701e9e56dc86509c1199ded2b33dce088c3471afcfef7839766d8e"},
   "file_system": {:hex, :file_system, "1.1.1", "31864f4685b0148f25bd3fbef2b1228457c0c89024ad67f7a81a3ffbc0bbad3a", [:mix], [], "hexpm", "7a15ff97dfe526aeefb090a7a9d3d03aa907e100e262a0f8f7746b78f8f87a5d"},
-  "finch": {:hex, :finch, "0.22.0", "5c48fa6f9706a78eb9036cacb67b8b996b4e66d111c543f4c29bb0f879a6806b", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b94e83c47780fc6813f746a1f1a34ee65cda42da4c5ea26a68f0acc4498e23dc"},
+  "finch": {:hex, :finch, "0.23.0", "e3f9287ac25a8832f848b144c2b57346aac65b205e2e0629a52adfe6507fd837", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "80e58d3f936f57e3fdf404f83a3642897ae6d9fb642934e46da4d8fe761b99d5"},
   "floki": {:hex, :floki, "0.38.1", "f002ccac94b3bcb21d40d9b34cc2cc9fd88a8311879120330075b5dde657ebee", [:mix], [], "hexpm", "e744bf0db7ee34b2c8b62767f04071107af0516a81144b9a2f73fe0494200e5b"},
-  "glob_ex": {:hex, :glob_ex, "0.1.11", "cb50d3f1ef53f6ca04d6252c7fde09fd7a1cf63387714fe96f340a1349e62c93", [:mix], [], "hexpm", "342729363056e3145e61766b416769984c329e4378f1d558b63e341020525de4"},
-  "hex_solver": {:hex, :hex_solver, "0.2.3", "0d2ee20fbceb251d573f03ef34852e325529c2874ab66d1b576384021318996c", [:mix], [], "hexpm", "9daeae2ea6b8ad3dc7f51a10484f6bc1d0f705c31063383830a7167ab93b887b"},
-  "hpax": {:hex, :hpax, "1.0.3", "ed67ef51ad4df91e75cc6a1494f851850c0bd98ebc0be6e81b026e765ee535aa", [:mix], [], "hexpm", "8eab6e1cfa8d5918c2ce4ba43588e894af35dbd8e91e6e55c817bca5847df34a"},
+  "glob_ex": {:hex, :glob_ex, "0.1.12", "7b2d9369c20e2697efcfd185d13d6e84c94cd3bfd2730fbde613141c2e015c00", [:mix], [], "hexpm", "2e2fac83f113514434c7eaf267b4c38af2f91766f1cab2c5db7053b7fc1ee0bb"},
+  "hex_solver": {:hex, :hex_solver, "0.3.0", "81e7659ad6caba1f856d89fc7ca52f88e8eb4f801deedcdce215f9006d706d1d", [:mix], [], "hexpm", "8a04c8ef0df25ca1f5e4d7d5f32833fac569f5c6442f05e216ee33615593e64d"},
+  "hpax": {:hex, :hpax, "1.0.4", "777de5d433b0fbdc7c418159c8055910faa8047ffdb3d6b31098d2a46cd7685c", [:mix], [], "hexpm", "afc7cb142ebcc2d01ce7816190b98ce5dd49e799111b24249f3443d730f377ca"},
   "jason": {:hex, :jason, "1.4.5", "2e3a008590b0b8d7388c20293e9dcc9cf3e5d642fd2a114e4cbbb52e595d940a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b0c823996102bcd0239b3c2444eb00409b72f6a140c1950bc8b457d836b30684"},
+  "json_codec": {:hex, :json_codec, "0.2.5", "4463d9db729ba994c356a0598b9a88ec0956a77e7ab778318d128b43db665faa", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:json_spec, "~> 1.2", [hex: :json_spec, repo: "hexpm", optional: false]}], "hexpm", "b32f189249cda0954a5fb6f4aab720444b5f3f81272869ce90098eea2418d465"},
+  "json_spec": {:hex, :json_spec, "1.2.0", "c67f73cdc4166e955b2f1095d3f44dd78c197337038f1a5301fb526b6c87ab04", [:mix], [], "hexpm", "3639961babad7d6bc45f3a2d96a49c18ec70614761bb84ce58b64e9fad9354de"},
   "mime": {:hex, :mime, "2.0.7", "b8d739037be7cd402aee1ba0306edfdef982687ee7e9859bee6198c1e7e2f128", [:mix], [], "hexpm", "6171188e399ee16023ffc5b76ce445eb6d9672e2e241d2df6050f3c771e80ccd"},
-  "mint": {:hex, :mint, "1.8.0", "b964eaf4416f2dee2ba88968d52239fca5621b0402b9c95f55a08eb9d74803e9", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "f3c572c11355eccf00f22275e9b42463bc17bd28db13be1e28f8e0bb4adbc849"},
-  "mint_web_socket": {:hex, :mint_web_socket, "1.0.5", "60354efeb49b1eccf95dfb75f55b08d692e211970fe735a5eb3188b328be2a90", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "04b35663448fc758f3356cce4d6ac067ca418bbafe6972a3805df984b5f12e61"},
+  "mint": {:hex, :mint, "1.10.0", "85af3353bfc504f5bdfe494bd92b8490f87a306dc659ee1ad0af435107e898dc", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "8b16fb72aaa7531d206a1f05e4cc85509ba531ccec7a17a22736c9c95cbb24d1"},
+  "mint_web_socket": {:hex, :mint_web_socket, "1.0.6", "5ffcf350df5b90f2d7a04adf877165228804993714592512374218d4679e325a", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "0c360e9012413f1c115a63532601eb5d63731aab7010949178769760686c1698"},
   "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.2", "8efba0122db06df95bfaa78f791344a89352ba04baedd3849593bfce4d0dc1c6", [:mix], [], "hexpm", "4b21398942dda052b403bbe1da991ccd03a053668d147d53fb8c4e0efe09c973"},
   "nimble_pool": {:hex, :nimble_pool, "1.1.0", "bf9c29fbdcba3564a8b800d1eeb5a3c58f36e1e11d7b7fb2e084a643f645f06b", [:mix], [], "hexpm", "af2e4e6b34197db81f7aad230c1118eac993acc0dae6bc83bac0126d4ae0813a"},
-  "npm": {:hex, :npm, "0.7.4", "a8cc2e760a30789e6b590257cfae9384fd1de470dab8ef62a7b35859587f34b7", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "ee265d380c19dbb9d1bba50458e1938711569a195423e6cfbf9ef7c3b8d7658a"},
+  "npm": {:hex, :npm, "0.7.6", "de8ca3dd26a40fac7ab8a17680088b8d55bab0e0294be9770b029c276361482f", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "e0a1ce77e3e49ec108e095aba133bd315e86da298dba26b142a105972141d9ef"},
   "npm_semver": {:hex, :npm_semver, "0.1.0", "3ab2c2a151d8c87c364209b2ca1a4fd2ab98507ed61afbd1ea12c1826e67200a", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "77afbc4c523c19a572325190bc4c968ec027e1c6ef8538bcddacf835966072fa"},
-  "oxc": {:hex, :oxc, "0.15.1", "d4b1770f26cd80b84ac592a54db38c50af92c98ce480be2ae1badbc0eccd614e", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "1008f80d04b961f5f262a0aec99781f3a73e5c4c7fc969f4336ca96f653c7d58"},
-  "oxide_ex": {:hex, :oxide_ex, "0.2.1", "ff0e1c03f58c151ca87e3b11847801a751853894fd926910f459ef5918cc655a", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "25bebc0d30362dead560e815a1380c266d018924a71a548ea2b1582f8dcd77bb"},
-  "phoenix": {:hex, :phoenix, "1.8.5", "919db335247e6d4891764dc3063415b0d2457641c5f9b3751b5df03d8e20bbcf", [:mix], [{:bandit, "~> 1.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.7", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5.3", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "83b2bb125127e02e9f475c8e3e92736325b5b01b0b9b05407bcb4083b7a32485"},
+  "oxc": {:hex, :oxc, "0.17.8", "e4c50ee0c0ce09107016b5153132b3d98421665355189b531c78ae4603047853", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "590fddfadbf843d6ab94e0f04a0e769a38358a23140728095da476c8c81f4df1"},
+  "oxide_ex": {:hex, :oxide_ex, "0.2.2", "063e0d2899e81632b7efc7849eb1dd89a7a623290a075c446b43bef14cf5795e", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "577a2fbd97c46904a31143bb700cdb374105085cfd1f7605416bb6c012cb7f60"},
+  "phoenix": {:hex, :phoenix, "1.8.14", "9279cbbcd755ac8d5f42d206915e7df13b9ab49096b98114f1c99ff908e5b42e", [:mix], [{:bandit, "~> 1.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.7", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 2.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "2782ff375824b2b5e41561fbae4764ee7b875af6898483bca49f24a9d1e37816"},
   "phoenix_html": {:hex, :phoenix_html, "4.3.0", "d3577a5df4b6954cd7890c84d955c470b5310bb49647f0a114a6eeecc850f7ad", [:mix], [], "hexpm", "3eaa290a78bab0f075f791a46a981bbe769d94bc776869f4f3063a14f30497ad"},
   "phoenix_live_reload": {:hex, :phoenix_live_reload, "1.6.2", "b18b0773a1ba77f28c52decbb0f10fd1ac4d3ae5b8632399bbf6986e3b665f62", [:mix], [{:file_system, "~> 0.2.10 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:phoenix, "~> 1.4", [hex: :phoenix, repo: "hexpm", optional: false]}], "hexpm", "d1f89c18114c50d394721365ffb428cce24f1c13de0467ffa773e2ff4a30d5b9"},
-  "phoenix_live_view": {:hex, :phoenix_live_view, "1.1.28", "8a8e123d018025f756605a2fb02a4854f0d3cd7b207f710fef1fd5d9d72d0254", [:mix], [{:igniter, ">= 0.6.16 and < 1.0.0-0", [hex: :igniter, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:lazy_html, "~> 0.1.0", [hex: :lazy_html, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0-rc", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "24faad535b65089642c3a7d84088109dc58f49c1f1c5a978659855d643466353"},
-  "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.2.0", "ff3a5616e1bed6804de7773b92cbccfc0b0f473faf1f63d7daf1206c7aeaaa6f", [:mix], [], "hexpm", "adc313a5bf7136039f63cfd9668fde73bba0765e0614cba80c06ac9460ff3e96"},
+  "phoenix_live_view": {:hex, :phoenix_live_view, "1.1.33", "8350c8bebabfa318c9afb0970eacced9174cd72603c9be2240e99d550fcc2eed", [:mix], [{:igniter, ">= 0.6.16 and < 1.0.0-0", [hex: :igniter, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:lazy_html, "~> 0.1.0", [hex: :lazy_html, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0-rc", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "2030f7987f641a269634e021bcde9373e5dea993f9373e628a44da86b2330b6c"},
+  "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.3.0", "03916bfbc31a5121945b3cfffe5aec647a5c97fe1dc172a319b94428562359c9", [:mix], [], "hexpm", "eec7be6e9cf02e2551d389b558402d6c637cd3973796326e7ba4bb03c6b2e91d"},
   "phoenix_template": {:hex, :phoenix_template, "1.0.4", "e2092c132f3b5e5b2d49c96695342eb36d0ed514c5b252a77048d5969330d639", [:mix], [{:phoenix_html, "~> 2.14.2 or ~> 3.0 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: true]}], "hexpm", "2c0c81f0e5c6753faf5cca2f229c9709919aba34fab866d3bc05060c9c444206"},
-  "plug": {:hex, :plug, "1.19.2", "e4950525b22c6789dfb38a3f95d47171ba159da3fc5a33be9643b43d5e8adb98", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b6fce20a56af5e60fa5dfecf3f907bb98ec981be43c79a3809a499bc3d133de0"},
-  "plug_crypto": {:hex, :plug_crypto, "2.1.1", "19bda8184399cb24afa10be734f84a16ea0a2bc65054e23a62bb10f06bc89491", [:mix], [], "hexpm", "6470bce6ffe41c8bd497612ffde1a7e4af67f36a15eea5f921af71cf3e11247c"},
-  "quickbeam": {:hex, :quickbeam, "0.10.15", "8622e090ba8476b4a7c008ddb75c741e770f45e64f9fc30c43b02694213a8605", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.4", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.15.0", [hex: :oxc, repo: "hexpm", optional: false]}, {:zigler, "~> 0.15.2", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.4", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "2da3750f1e99ae1d97b6e99a2b8ea86ba48c49c568d8f711d65d342430dcfb86"},
-  "req": {:hex, :req, "0.5.18", "48e6431cb4135e8a7815e745177485369a9b4a9924d5fe68ca00eb09ceaed1ef", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.21.0 or ~> 0.22.0", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "fa03812c440a9754bf34355e0c5d4f3ed316458db62e3284b7a352ef8dc0b996"},
+  "plug": {:hex, :plug, "1.20.3", "56c480c633ec2ce10140e236e15233bf576e1d323887d7c96711bd02ab5160db", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "be266aee1b8536ef6409d58cf39a3121319f0ec47cfa1b24024485aa0e76ad76"},
+  "plug_crypto": {:hex, :plug_crypto, "2.2.0", "144014737daaf485407f5ed77daeaad74d651b216a28c87543f8cc7043f8efc8", [:mix], [], "hexpm", "83a95744ab1c75876542b6fab135fcc176280e0f301a111c1f757fddcec95d2c"},
+  "quickbeam": {:hex, :quickbeam, "0.11.1", "55e7700b2a16c8df246402f8400908222e906f3b463af4ac8706f748d83b66db", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:mint, "~> 1.10", [hex: :mint, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.6", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.17.8", [hex: :oxc, repo: "hexpm", optional: false]}, {:varint, "~> 1.6", [hex: :varint, repo: "hexpm", optional: false]}, {:zigler, "~> 0.16.0", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.6", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "6c0240b9d016bbc174319ef004e81f2893ae2e77939d6b9b87c5542b344d0b87"},
+  "req": {:hex, :req, "0.7.4", "23e9ffec17de032a46a4b15ed65c09793893bf4a7c680f4bbf6227fce6bdf74d", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:finch, "~> 0.21", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "4b192d63253e8dcc6221ef992ea9ebef7d3555166e8423aa5b553e86bc3c69a2"},
   "rustler_precompiled": {:hex, :rustler_precompiled, "0.9.0", "3a052eda09f3d2436364645cc1f13279cf95db310eb0c17b0d8f25484b233aa0", [:mix], [{:rustler, "~> 0.23", [hex: :rustler, repo: "hexpm", optional: true]}], "hexpm", "471d97315bd3bf7b64623418b3693eedd8e47de3d1cb79a0ac8f9da7d770d94c"},
   "telemetry": {:hex, :telemetry, "1.4.2", "a0cb522801dffb1c49fe6e30561badffc7b6d0e180db1300df759faa22062855", [:rebar3], [], "hexpm", "928f6495066506077862c0d1646609eed891a4326bee3126ba54b60af61febb1"},
   "telemetry_metrics": {:hex, :telemetry_metrics, "1.1.0", "5bd5f3b5637e0abea0426b947e3ce5dd304f8b3bc6617039e2b5a008adc02f8f", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "e7b79e8ddfde70adb6db8a6623d1778ec66401f366e9a8f5dd0955c56bc8ce67"},
   "telemetry_poller": {:hex, :telemetry_poller, "1.3.0", "d5c46420126b5ac2d72bc6580fb4f537d35e851cc0f8dbd571acf6d6e10f5ec7", [:rebar3], [{:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "51f18bed7128544a50f75897db9974436ea9bfba560420b646af27a9a9b35211"},
-  "thousand_island": {:hex, :thousand_island, "1.4.3", "2158209580f633be38d43ec4e3ce0a01079592b9657afff9080d5d8ca149a3af", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "6e4ce09b0fd761a58594d02814d40f77daff460c48a7354a15ab353bb998ea0b"},
-  "vize": {:hex, :vize, "0.11.1", "eda811711b1663e548936b44ede72eac9bad1efdc1ff24be7ae86ea3b03541d2", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "9d53506c28c8c2a1947322d23fcb95c20e8c4d9ddb2e33b10c794e497ee55c5a"},
+  "thousand_island": {:hex, :thousand_island, "1.5.0", "f50a213cac97262b6d5ebb85745aa2c00fec1413191e6e66834788d45425cecb", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "708923d40523e43cf99041ab37a0d4b0ec426ac6438fa3716ab23d919eaeb412"},
+  "varint": {:hex, :varint, "1.6.0", "7bced828599b2eb84491a9f067f8a5a67fc35a946d3b7582278083c7fd434b00", [:mix], [], "hexpm", "2b4f4a20650aeebe993a70b03bb99571bcbddc27c361322c28b586d8a772ce4e"},
+  "vize": {:hex, :vize, "0.14.2", "4baf40c18e00963ce802c03ebb664feaccd8558d7ec62aa43fb07ad8485d0208", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "8336744616bc27ce4edc7448cda6f0b8a481cbec9035d3c4d6bf3229be91386d"},
   "websock": {:hex, :websock, "0.5.3", "2f69a6ebe810328555b6fe5c831a851f485e303a7c8ce6c5f675abeb20ebdadc", [:mix], [], "hexpm", "6105453d7fac22c712ad66fab1d45abdf049868f253cf719b625151460b8b453"},
-  "websock_adapter": {:hex, :websock_adapter, "0.5.9", "43dc3ba6d89ef5dec5b1d0a39698436a1e856d000d84bf31a3149862b01a287f", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "5534d5c9adad3c18a0f58a9371220d75a803bf0b9a3d87e6fe072faaeed76a08"},
-  "zigler_precompiled": {:hex, :zigler_precompiled, "0.1.4", "20a166584b94d860a983ef39c93cb0a9ce40c95c48555fc3cb6532c405558410", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:zigler, "~> 0.13", [hex: :zigler, repo: "hexpm", optional: true]}], "hexpm", "9cd6998a8ddf2f03ded1b6ebc9acb9bfa5e23b614f047583c76c01bf66c4640e"},
+  "websock_adapter": {:hex, :websock_adapter, "0.6.0", "73db5ab8aaefd1a876a97ce3e6afc96562625de69ef17a4e04426e034849d0b8", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "50021a85bce8f203b086705d9e0c5415e2c7eb05d319111b0428fe71f9934617"},
+  "zigler_precompiled": {:hex, :zigler_precompiled, "0.1.6", "1c5c889ff30164eb340e599ae987b6c51c3ba0654117ec7a68a6b83d4df39310", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:zigler, "~> 0.13", [hex: :zigler, repo: "hexpm", optional: true]}], "hexpm", "5754d342533b2fb8e767c0ef216ee13c928e17f317cac7d6a01a0972ba68ce4a"},
 }
diff --git a/examples/vanilla/.formatter.exs b/examples/vanilla/.formatter.exs
index a0877aa..daa575d 100644
--- a/examples/vanilla/.formatter.exs
+++ b/examples/vanilla/.formatter.exs
@@ -5,5 +5,6 @@
     "*.{heex,ex,exs}",
     "{config,lib,test}/**/*.{heex,ex,exs}",
     "assets/**/*.{js,ts,jsx,tsx}"
-  ]
+  ],
+  volt: [semi: false, single_quote: true]
 ]
diff --git a/examples/vanilla/config/config.exs b/examples/vanilla/config/config.exs
index 24684b4..82f1b8d 100644
--- a/examples/vanilla/config/config.exs
+++ b/examples/vanilla/config/config.exs
@@ -23,7 +23,6 @@ config :volt,
   sources: ["**/*.{js,ts}"],
   target: :es2020,
   minify: false,
-  hash: false,
   resolve_dirs: ["node_modules", "deps", Mix.Project.build_path()],
   tailwind: [
     css: "assets/css/app.css",
@@ -33,12 +32,8 @@ config :volt,
     ]
   ]
 
-config :volt, :format,
-  semi: false,
-  single_quote: true
-
 config :volt, :lint,
-  plugins: [:typescript],
+  plugins: ["typescript"],
   tsgolint: System.find_executable("tsgolint"),
   rules: %{
     "correctness" => :deny,
diff --git a/examples/vanilla/lib/vanilla_example_web/components/layouts/root.html.heex b/examples/vanilla/lib/vanilla_example_web/components/layouts/root.html.heex
index a61e1a3..67cdddc 100644
--- a/examples/vanilla/lib/vanilla_example_web/components/layouts/root.html.heex
+++ b/examples/vanilla/lib/vanilla_example_web/components/layouts/root.html.heex
@@ -5,7 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <meta name="csrf-token" content={get_csrf_token()} />
     <.live_title default="Volt Vanilla Example">Volt Vanilla Example</.live_title>
-    <link phx-track-static rel="stylesheet" href={~p"/assets/css/app.css"} />
+    <link phx-track-static rel="stylesheet" href={Volt.static_path(VanillaExampleWeb.Endpoint, "/assets/css/app.css")} />
     <script defer phx-track-static type="module" src={Volt.static_path(VanillaExampleWeb.Endpoint, "/assets/js/app.js")}></script>
   </head>
   <body>
diff --git a/examples/vanilla/mix.exs b/examples/vanilla/mix.exs
index 36e73db..9f98dbc 100644
--- a/examples/vanilla/mix.exs
+++ b/examples/vanilla/mix.exs
@@ -35,16 +35,18 @@ defmodule VanillaExample.MixProject do
       {:telemetry_poller, "~> 1.0"},
       {:jason, "~> 1.2"},
       {:dns_cluster, "~> 0.2.0"},
-      {:bandit, "~> 1.5"},
-      {:volt, path: "../..", override: true}
+      {:bandit, ">= 1.12.5 and < 2.0.0"},
+      {:volt, path: "../..", override: true},
+      {:lumis, "~> 0.10", only: :dev},
+      {:lumis_wasm_typescript, "~> 0.26", only: :dev}
     ]
   end
 
   defp aliases do
     [
       setup: ["deps.get", "npm.install", "assets.build"],
-      "assets.build": ["volt.build --tailwind --no-hash --no-minify"],
-      "assets.deploy": ["volt.build --tailwind --no-hash", "phx.digest"],
+      "assets.build": ["volt.build --tailwind --no-minify"],
+      "assets.deploy": ["volt.build --tailwind", "phx.digest"],
       "assets.check": ["volt.js.check"],
       "assets.check.type_aware": ["volt.js.check --type-aware --type-check"],
       precommit: ["compile --warnings-as-errors", "format", "test"]
diff --git a/examples/vanilla/mix.lock b/examples/vanilla/mix.lock
index f85d5b5..c74d820 100644
--- a/examples/vanilla/mix.lock
+++ b/examples/vanilla/mix.lock
@@ -1,43 +1,47 @@
 %{
-  "bandit": {:hex, :bandit, "1.12.0", "6c5214daa2469644ac4ab0113b98abc24f75e348378e6a974c6343b3e5da22ef", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.5", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "45dac82dc86f45cf4a196dee9cc5a8b791d9c9469d996055f055e6ee36c66e20"},
-  "castore": {:hex, :castore, "1.0.19", "6903cabdfd9d1af46454126e7c8385186659dd33ecfb74a885cae52221ad6109", [:mix], [], "hexpm", "3669e6cab13f54c2df26b3e6833745d647f35b6e30d8ddd5975df0d5c842ca98"},
+  "bandit": {:hex, :bandit, "1.12.5", "af205a8e550f304caae09a97d29fd3c79a7f337526ea7cd772d2ff11d2f7c800", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.5", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "c5684ca062fa407cac115aec3256383f3e2ec9fdced7904d59cf5a7bb7ed6181"},
+  "castore": {:hex, :castore, "1.0.21", "0a0e8330dc267a40a3b7ad86d39302764bb71758172904e6a59d5ad6443ce307", [:mix], [], "hexpm", "e42e22723e25dbd46876d056a03f685513d6e98f6b5e555dc551321decd76c5c"},
   "dns_cluster": {:hex, :dns_cluster, "0.2.0", "aa8eb46e3bd0326bd67b84790c561733b25c5ba2fe3c7e36f28e88f384ebcb33", [:mix], [], "hexpm", "ba6f1893411c69c01b9e8e8f772062535a4cf70f3f35bcc964a324078d8c8240"},
   "dotenvy": {:hex, :dotenvy, "1.1.1", "00e318f3c51de9fafc4b48598447e386f19204dc18ca69886905bb8f8b08b667", [:mix], [], "hexpm", "c8269471b5701e9e56dc86509c1199ded2b33dce088c3471afcfef7839766d8e"},
   "file_system": {:hex, :file_system, "1.1.1", "31864f4685b0148f25bd3fbef2b1228457c0c89024ad67f7a81a3ffbc0bbad3a", [:mix], [], "hexpm", "7a15ff97dfe526aeefb090a7a9d3d03aa907e100e262a0f8f7746b78f8f87a5d"},
-  "finch": {:hex, :finch, "0.23.0", "e3f9287ac25a8832f848b144c2b57346aac65b205e2e0629a52adfe6507fd837", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "80e58d3f936f57e3fdf404f83a3642897ae6d9fb642934e46da4d8fe761b99d5"},
+  "finch": {:hex, :finch, "0.24.0", "4022b6194e907b6d9b597c168001cac38e488a35fe36cef9d8297e3159782510", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "33ba40069c3587c2f99f9125b766e19dad87d6d54be3c6961db2304df04cef00"},
   "floki": {:hex, :floki, "0.38.1", "f002ccac94b3bcb21d40d9b34cc2cc9fd88a8311879120330075b5dde657ebee", [:mix], [], "hexpm", "e744bf0db7ee34b2c8b62767f04071107af0516a81144b9a2f73fe0494200e5b"},
-  "glob_ex": {:hex, :glob_ex, "0.1.11", "cb50d3f1ef53f6ca04d6252c7fde09fd7a1cf63387714fe96f340a1349e62c93", [:mix], [], "hexpm", "342729363056e3145e61766b416769984c329e4378f1d558b63e341020525de4"},
-  "hex_solver": {:hex, :hex_solver, "0.2.3", "0d2ee20fbceb251d573f03ef34852e325529c2874ab66d1b576384021318996c", [:mix], [], "hexpm", "9daeae2ea6b8ad3dc7f51a10484f6bc1d0f705c31063383830a7167ab93b887b"},
-  "hpax": {:hex, :hpax, "1.0.4", "777de5d433b0fbdc7c418159c8055910faa8047ffdb3d6b31098d2a46cd7685c", [:mix], [], "hexpm", "afc7cb142ebcc2d01ce7816190b98ce5dd49e799111b24249f3443d730f377ca"},
+  "glob_ex": {:hex, :glob_ex, "0.1.12", "7b2d9369c20e2697efcfd185d13d6e84c94cd3bfd2730fbde613141c2e015c00", [:mix], [], "hexpm", "2e2fac83f113514434c7eaf267b4c38af2f91766f1cab2c5db7053b7fc1ee0bb"},
+  "hex_solver": {:hex, :hex_solver, "0.3.0", "81e7659ad6caba1f856d89fc7ca52f88e8eb4f801deedcdce215f9006d706d1d", [:mix], [], "hexpm", "8a04c8ef0df25ca1f5e4d7d5f32833fac569f5c6442f05e216ee33615593e64d"},
+  "hpax": {:hex, :hpax, "1.1.0", "782931867cc23217c68fb5f68fe1a11f5e7544c7fda82c8a7019a5df5a4a1cdf", [:mix], [], "hexpm", "0b8d0f05832f55571d65ac720f79bf8994138ffbb133209dc4685eae0ad456a8"},
   "jason": {:hex, :jason, "1.4.5", "2e3a008590b0b8d7388c20293e9dcc9cf3e5d642fd2a114e4cbbb52e595d940a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b0c823996102bcd0239b3c2444eb00409b72f6a140c1950bc8b457d836b30684"},
-  "json_codec": {:hex, :json_codec, "0.1.6", "50493aa3daf952f9c71a828112e25d7e6dde9622d33571981ba485892b5bbb7f", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "cda1825c2e2cbb7d8b90833ee72867aee1a3802772bc2ff1e12b61f2801554ec"},
+  "json_codec": {:hex, :json_codec, "0.3.1", "81f738e212308c85344e11da00af6d8b52bd486224ee24c1f51b95df0604aeae", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: true]}, {:json_spec, "~> 1.2", [hex: :json_spec, repo: "hexpm", optional: false]}], "hexpm", "dffea3198d3f1fe9a39aa176ab0d6988b8c80dd85a67e913b323d4ec7c57ca9d"},
+  "json_spec": {:hex, :json_spec, "1.2.0", "c67f73cdc4166e955b2f1095d3f44dd78c197337038f1a5301fb526b6c87ab04", [:mix], [], "hexpm", "3639961babad7d6bc45f3a2d96a49c18ec70614761bb84ce58b64e9fad9354de"},
+  "lumis": {:hex, :lumis, "0.10.0", "4b0b773447f7dace8be7b0c93abe4d24e9b7c81034ac2757003f3ac4b7ac3450", [:mix], [{:nimble_options, "~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:rustler, "~> 0.29", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "5e3845defa32871a404d6a51ad2d8d3c423077f6f80149e632511f26460f27dc"},
+  "lumis_wasm_typescript": {:hex, :lumis_wasm_typescript, "0.26.2", "6f6972ba900860bfa5b601333a216faa24a9e1f59dac84b2beae3911941b006b", [:mix], [], "hexpm", "277acc22eb48133299e137ba5f127bf635409192dd5f5c6f5839e52fd7c0bc72"},
   "mime": {:hex, :mime, "2.0.7", "b8d739037be7cd402aee1ba0306edfdef982687ee7e9859bee6198c1e7e2f128", [:mix], [], "hexpm", "6171188e399ee16023ffc5b76ce445eb6d9672e2e241d2df6050f3c771e80ccd"},
-  "mint": {:hex, :mint, "1.9.1", "3bc120b743ed2e99ad920910f2613e9faebabb2257731b0e2ea4d8ccd9eceede", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "831101bd560b086316fab5f7adb21a4f3455717d8e4bc8368b052e09aa9163e0"},
-  "mint_web_socket": {:hex, :mint_web_socket, "1.0.5", "60354efeb49b1eccf95dfb75f55b08d692e211970fe735a5eb3188b328be2a90", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "04b35663448fc758f3356cce4d6ac067ca418bbafe6972a3805df984b5f12e61"},
+  "mint": {:hex, :mint, "1.11.0", "a713551624815c0435237b93d90ea8b9b14254690c66f732d0ef8930f76ff1d9", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 1.1", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "c6279ba2d6aa3a383a1d4cfbe7b59f42e6efd400f58d8e2acfeac48a438693ab"},
+  "mint_web_socket": {:hex, :mint_web_socket, "1.0.6", "5ffcf350df5b90f2d7a04adf877165228804993714592512374218d4679e325a", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "0c360e9012413f1c115a63532601eb5d63731aab7010949178769760686c1698"},
   "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.2", "8efba0122db06df95bfaa78f791344a89352ba04baedd3849593bfce4d0dc1c6", [:mix], [], "hexpm", "4b21398942dda052b403bbe1da991ccd03a053668d147d53fb8c4e0efe09c973"},
   "nimble_pool": {:hex, :nimble_pool, "1.1.0", "bf9c29fbdcba3564a8b800d1eeb5a3c58f36e1e11d7b7fb2e084a643f645f06b", [:mix], [], "hexpm", "af2e4e6b34197db81f7aad230c1118eac993acc0dae6bc83bac0126d4ae0813a"},
-  "npm": {:hex, :npm, "0.7.4", "a8cc2e760a30789e6b590257cfae9384fd1de470dab8ef62a7b35859587f34b7", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "ee265d380c19dbb9d1bba50458e1938711569a195423e6cfbf9ef7c3b8d7658a"},
+  "npm": {:hex, :npm, "0.7.6", "de8ca3dd26a40fac7ab8a17680088b8d55bab0e0294be9770b029c276361482f", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "e0a1ce77e3e49ec108e095aba133bd315e86da298dba26b142a105972141d9ef"},
   "npm_semver": {:hex, :npm_semver, "0.1.0", "3ab2c2a151d8c87c364209b2ca1a4fd2ab98507ed61afbd1ea12c1826e67200a", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "77afbc4c523c19a572325190bc4c968ec027e1c6ef8538bcddacf835966072fa"},
-  "oxc": {:hex, :oxc, "0.17.1", "5027b48bd667d615b7cafba88dd68ebf018dd9cde6a68274643dfd3dfd6306e1", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "e4f0d40a03d373244032c24dc27da407dceb4e1a096f6fb76f207436492f6c62"},
-  "oxide_ex": {:hex, :oxide_ex, "0.2.1", "ff0e1c03f58c151ca87e3b11847801a751853894fd926910f459ef5918cc655a", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "25bebc0d30362dead560e815a1380c266d018924a71a548ea2b1582f8dcd77bb"},
-  "phoenix": {:hex, :phoenix, "1.8.9", "a63ed0962ed5b903b146dab0ae8eb8387fe478f8171a5e26d56a165f35996fe1", [:mix], [{:bandit, "~> 1.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.7", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "3477e2dd5a4f61820341169031bdfe21275f659923bea9c5c0ea2aa1c3fcc046"},
+  "oxc": {:hex, :oxc, "0.18.0", "0b22ae1ac62f6e985458aae53bb0020756bd790ed07bcda1a89168b266025415", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:json_codec, "~> 0.3", [hex: :json_codec, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "121495bbbaba0807433653d4446cb9ed68bc7db35e6f11a9c82da56f89bcaa6c"},
+  "oxide_ex": {:hex, :oxide_ex, "0.2.2", "063e0d2899e81632b7efc7849eb1dd89a7a623290a075c446b43bef14cf5795e", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "577a2fbd97c46904a31143bb700cdb374105085cfd1f7605416bb6c012cb7f60"},
+  "phoenix": {:hex, :phoenix, "1.8.14", "9279cbbcd755ac8d5f42d206915e7df13b9ab49096b98114f1c99ff908e5b42e", [:mix], [{:bandit, "~> 1.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.7", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 2.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "2782ff375824b2b5e41561fbae4764ee7b875af6898483bca49f24a9d1e37816"},
   "phoenix_html": {:hex, :phoenix_html, "4.3.0", "d3577a5df4b6954cd7890c84d955c470b5310bb49647f0a114a6eeecc850f7ad", [:mix], [], "hexpm", "3eaa290a78bab0f075f791a46a981bbe769d94bc776869f4f3063a14f30497ad"},
   "phoenix_live_reload": {:hex, :phoenix_live_reload, "1.6.2", "b18b0773a1ba77f28c52decbb0f10fd1ac4d3ae5b8632399bbf6986e3b665f62", [:mix], [{:file_system, "~> 0.2.10 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:phoenix, "~> 1.4", [hex: :phoenix, repo: "hexpm", optional: false]}], "hexpm", "d1f89c18114c50d394721365ffb428cce24f1c13de0467ffa773e2ff4a30d5b9"},
-  "phoenix_live_view": {:hex, :phoenix_live_view, "1.2.6", "b2b50c51993b068fe2a29eda45ca4fe67bf74f146343468485686a253c65a8da", [:mix], [{:igniter, ">= 0.6.16 and < 1.0.0-0", [hex: :igniter, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:lazy_html, "~> 0.1.0", [hex: :lazy_html, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "5dc549a78dab94e80a340c760090e9e7bab16ac47841e34f4fff5819e02cbf35"},
-  "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.2.0", "ff3a5616e1bed6804de7773b92cbccfc0b0f473faf1f63d7daf1206c7aeaaa6f", [:mix], [], "hexpm", "adc313a5bf7136039f63cfd9668fde73bba0765e0614cba80c06ac9460ff3e96"},
+  "phoenix_live_view": {:hex, :phoenix_live_view, "1.2.11", "1c83fdfd007e8d554076baee00ee6f55bb9c87ad9439f33ee520e47ae4a983bb", [:mix], [{:igniter, ">= 0.6.16 and < 1.0.0-0", [hex: :igniter, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:lazy_html, "~> 0.1.0", [hex: :lazy_html, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "c4087267cbd4dc4ed7ac36512a97830af8e9c857ca7cb22557f8640fc5f9d306"},
+  "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.3.0", "03916bfbc31a5121945b3cfffe5aec647a5c97fe1dc172a319b94428562359c9", [:mix], [], "hexpm", "eec7be6e9cf02e2551d389b558402d6c637cd3973796326e7ba4bb03c6b2e91d"},
   "phoenix_template": {:hex, :phoenix_template, "1.0.4", "e2092c132f3b5e5b2d49c96695342eb36d0ed514c5b252a77048d5969330d639", [:mix], [{:phoenix_html, "~> 2.14.2 or ~> 3.0 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: true]}], "hexpm", "2c0c81f0e5c6753faf5cca2f229c9709919aba34fab866d3bc05060c9c444206"},
-  "plug": {:hex, :plug, "1.20.2", "adbee2441232412e37fbb357fd5e4cd533fdd253b29f2e1992262b0f1fb01462", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b16baf55877d60891002ffc1ce0b3ff7d6f30a38a23e02e4d4293c4ac266f136"},
-  "plug_crypto": {:hex, :plug_crypto, "2.1.1", "19bda8184399cb24afa10be734f84a16ea0a2bc65054e23a62bb10f06bc89491", [:mix], [], "hexpm", "6470bce6ffe41c8bd497612ffde1a7e4af67f36a15eea5f921af71cf3e11247c"},
-  "quickbeam": {:hex, :quickbeam, "0.10.18", "b6e655af25b4aa56464a1f273f52948e95fed59bb15349a2f0d22d02b578edb0", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.4", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.17.1", [hex: :oxc, repo: "hexpm", optional: false]}, {:zigler, "~> 0.15.2", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.4", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "71439528a9be63bfd0b052306952c96f3e99fc7bef03dea7e8859d61d84a43d5"},
-  "req": {:hex, :req, "0.6.2", "b9b2024f35bcf60a92cc8cad2eaaf9d4e7aace463ff74be1afe5986830184413", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.21", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "cc9cd30a2ddd04989929b887178e1610c940456d962c6c3a52df6146d2eef9bf"},
-  "rustler_precompiled": {:hex, :rustler_precompiled, "0.9.0", "3a052eda09f3d2436364645cc1f13279cf95db310eb0c17b0d8f25484b233aa0", [:mix], [{:rustler, "~> 0.23", [hex: :rustler, repo: "hexpm", optional: true]}], "hexpm", "471d97315bd3bf7b64623418b3693eedd8e47de3d1cb79a0ac8f9da7d770d94c"},
+  "plug": {:hex, :plug, "1.20.3", "56c480c633ec2ce10140e236e15233bf576e1d323887d7c96711bd02ab5160db", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "be266aee1b8536ef6409d58cf39a3121319f0ec47cfa1b24024485aa0e76ad76"},
+  "plug_crypto": {:hex, :plug_crypto, "2.2.0", "144014737daaf485407f5ed77daeaad74d651b216a28c87543f8cc7043f8efc8", [:mix], [], "hexpm", "83a95744ab1c75876542b6fab135fcc176280e0f301a111c1f757fddcec95d2c"},
+  "quickbeam": {:hex, :quickbeam, "0.11.2", "ea4e4bfd7a8999381f86b773b13d028c02753137f8b56c1d3f3cce4649dfee71", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:json_codec, "~> 0.3", [hex: :json_codec, repo: "hexpm", optional: true]}, {:mint, "~> 1.10", [hex: :mint, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.6", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.17.8 or ~> 0.18.0", [hex: :oxc, repo: "hexpm", optional: false]}, {:varint, "~> 1.6", [hex: :varint, repo: "hexpm", optional: false]}, {:zigler, "~> 0.16.0", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.6", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "f7652948f43484fcc5c0fe007fdcddbd62db595daa16a6f53fb9b3553f66c608"},
+  "req": {:hex, :req, "0.7.4", "23e9ffec17de032a46a4b15ed65c09793893bf4a7c680f4bbf6227fce6bdf74d", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:finch, "~> 0.21", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "4b192d63253e8dcc6221ef992ea9ebef7d3555166e8423aa5b553e86bc3c69a2"},
+  "rustler_precompiled": {:hex, :rustler_precompiled, "0.10.0", "8f07ff0865cb09a6a0f75e11701e9a46e331e05f737da4e5b01374dcd25b68c0", [:mix], [{:rustler, "~> 0.28", [hex: :rustler, repo: "hexpm", optional: true]}], "hexpm", "c68c9dc732c12acfdf4a7fa06f4e6f48a641179e6be49a474c8a60809929c430"},
   "telemetry": {:hex, :telemetry, "1.4.2", "a0cb522801dffb1c49fe6e30561badffc7b6d0e180db1300df759faa22062855", [:rebar3], [], "hexpm", "928f6495066506077862c0d1646609eed891a4326bee3126ba54b60af61febb1"},
   "telemetry_metrics": {:hex, :telemetry_metrics, "1.1.0", "5bd5f3b5637e0abea0426b947e3ce5dd304f8b3bc6617039e2b5a008adc02f8f", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "e7b79e8ddfde70adb6db8a6623d1778ec66401f366e9a8f5dd0955c56bc8ce67"},
   "telemetry_poller": {:hex, :telemetry_poller, "1.3.0", "d5c46420126b5ac2d72bc6580fb4f537d35e851cc0f8dbd571acf6d6e10f5ec7", [:rebar3], [{:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "51f18bed7128544a50f75897db9974436ea9bfba560420b646af27a9a9b35211"},
   "thousand_island": {:hex, :thousand_island, "1.5.0", "f50a213cac97262b6d5ebb85745aa2c00fec1413191e6e66834788d45425cecb", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "708923d40523e43cf99041ab37a0d4b0ec426ac6438fa3716ab23d919eaeb412"},
-  "vize": {:hex, :vize, "0.13.1", "e125361d93a18b0362e45f2724cdb25aeef1b78d9f379c89841d1fc1f0cd24a6", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "56cb56fd6806a084aeb1f52a18948160eac693c37f032e724d2b8b955be4d206"},
+  "varint": {:hex, :varint, "1.6.0", "7bced828599b2eb84491a9f067f8a5a67fc35a946d3b7582278083c7fd434b00", [:mix], [], "hexpm", "2b4f4a20650aeebe993a70b03bb99571bcbddc27c361322c28b586d8a772ce4e"},
+  "vize": {:hex, :vize, "0.15.0", "f13eaecaa6a59c3314e374febc6b21e127560e08836f5d3e8edc4282412d182e", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "e1f2021c1e43d1f7530081dbf00ea93f6e55ea6928d10371a64e1214605316a0"},
   "websock": {:hex, :websock, "0.5.3", "2f69a6ebe810328555b6fe5c831a851f485e303a7c8ce6c5f675abeb20ebdadc", [:mix], [], "hexpm", "6105453d7fac22c712ad66fab1d45abdf049868f253cf719b625151460b8b453"},
   "websock_adapter": {:hex, :websock_adapter, "0.6.0", "73db5ab8aaefd1a876a97ce3e6afc96562625de69ef17a4e04426e034849d0b8", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "50021a85bce8f203b086705d9e0c5415e2c7eb05d319111b0428fe71f9934617"},
-  "zigler_precompiled": {:hex, :zigler_precompiled, "0.1.4", "20a166584b94d860a983ef39c93cb0a9ce40c95c48555fc3cb6532c405558410", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:zigler, "~> 0.13", [hex: :zigler, repo: "hexpm", optional: true]}], "hexpm", "9cd6998a8ddf2f03ded1b6ebc9acb9bfa5e23b614f047583c76c01bf66c4640e"},
+  "zigler_precompiled": {:hex, :zigler_precompiled, "0.1.6", "1c5c889ff30164eb340e599ae987b6c51c3ba0654117ec7a68a6b83d4df39310", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:zigler, "~> 0.13", [hex: :zigler, repo: "hexpm", optional: true]}], "hexpm", "5754d342533b2fb8e767c0ef216ee13c928e17f317cac7d6a01a0972ba68ce4a"},
 }
diff --git a/examples/vue/.formatter.exs b/examples/vue/.formatter.exs
index a0877aa..daa575d 100644
--- a/examples/vue/.formatter.exs
+++ b/examples/vue/.formatter.exs
@@ -5,5 +5,6 @@
     "*.{heex,ex,exs}",
     "{config,lib,test}/**/*.{heex,ex,exs}",
     "assets/**/*.{js,ts,jsx,tsx}"
-  ]
+  ],
+  volt: [semi: false, single_quote: true]
 ]
diff --git a/examples/vue/config/config.exs b/examples/vue/config/config.exs
index 87bf3a2..85409ab 100644
--- a/examples/vue/config/config.exs
+++ b/examples/vue/config/config.exs
@@ -23,7 +23,6 @@ config :volt,
   sources: ["**/*.{js,ts,jsx,tsx,vue}"],
   target: :es2020,
   minify: false,
-  hash: false,
   resolve_dirs: ["node_modules", "deps"],
   tailwind: [
     css: "assets/css/app.css",
@@ -33,12 +32,8 @@ config :volt,
     ]
   ]
 
-config :volt, :format,
-  semi: false,
-  single_quote: true
-
 config :volt, :lint,
-  plugins: [:typescript, :vue],
+  plugins: ["typescript", "vue"],
   tsgolint: System.find_executable("tsgolint"),
   rules: %{
     "correctness" => :deny,
diff --git a/examples/vue/lib/vue_example_web/components/layouts/root.html.heex b/examples/vue/lib/vue_example_web/components/layouts/root.html.heex
index 5b377a3..714dfa7 100644
--- a/examples/vue/lib/vue_example_web/components/layouts/root.html.heex
+++ b/examples/vue/lib/vue_example_web/components/layouts/root.html.heex
@@ -5,7 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <meta name="csrf-token" content={get_csrf_token()} />
     <.live_title default="Volt Vue Example">Volt Vue Example</.live_title>
-    <link phx-track-static rel="stylesheet" href={~p"/assets/css/app.css"} />
+    <link phx-track-static rel="stylesheet" href={Volt.static_path(VueExampleWeb.Endpoint, "/assets/css/app.css")} />
     <script defer phx-track-static type="module" src={Volt.entry_path(VueExampleWeb.Endpoint)}></script>
   </head>
   <body>
diff --git a/examples/vue/mix.exs b/examples/vue/mix.exs
index 8d84584..267fd7a 100644
--- a/examples/vue/mix.exs
+++ b/examples/vue/mix.exs
@@ -35,7 +35,7 @@ defmodule VueExample.MixProject do
       {:telemetry_poller, "~> 1.0"},
       {:jason, "~> 1.2"},
       {:dns_cluster, "~> 0.2.0"},
-      {:bandit, "~> 1.5"},
+      {:bandit, ">= 1.12.5 and < 2.0.0"},
       {:volt, path: "../..", override: true}
     ]
   end
@@ -43,8 +43,8 @@ defmodule VueExample.MixProject do
   defp aliases do
     [
       setup: ["deps.get", "npm.install", "assets.build"],
-      "assets.build": ["volt.build --tailwind --no-hash --no-minify"],
-      "assets.deploy": ["volt.build --tailwind --no-hash", "phx.digest"],
+      "assets.build": ["volt.build --tailwind --no-minify"],
+      "assets.deploy": ["volt.build --tailwind", "phx.digest"],
       "assets.check": ["volt.js.check"],
       "assets.check.type_aware": ["volt.js.check --type-aware --type-check"],
       precommit: ["compile --warnings-as-errors", "format", "test"]
diff --git a/examples/vue/mix.lock b/examples/vue/mix.lock
index e37aeb5..1e04617 100644
--- a/examples/vue/mix.lock
+++ b/examples/vue/mix.lock
@@ -1,42 +1,45 @@
 %{
-  "bandit": {:hex, :bandit, "1.10.4", "02b9734c67c5916a008e7eb7e2ba68aaea6f8177094a5f8d95f1fb99069aac17", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.0", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "a5faf501042ac1f31d736d9d4a813b3db4ef812e634583b6a457b0928798a51d"},
-  "castore": {:hex, :castore, "1.0.19", "6903cabdfd9d1af46454126e7c8385186659dd33ecfb74a885cae52221ad6109", [:mix], [], "hexpm", "3669e6cab13f54c2df26b3e6833745d647f35b6e30d8ddd5975df0d5c842ca98"},
+  "bandit": {:hex, :bandit, "1.12.5", "af205a8e550f304caae09a97d29fd3c79a7f337526ea7cd772d2ff11d2f7c800", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.5", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "c5684ca062fa407cac115aec3256383f3e2ec9fdced7904d59cf5a7bb7ed6181"},
+  "castore": {:hex, :castore, "1.0.21", "0a0e8330dc267a40a3b7ad86d39302764bb71758172904e6a59d5ad6443ce307", [:mix], [], "hexpm", "e42e22723e25dbd46876d056a03f685513d6e98f6b5e555dc551321decd76c5c"},
   "dns_cluster": {:hex, :dns_cluster, "0.2.0", "aa8eb46e3bd0326bd67b84790c561733b25c5ba2fe3c7e36f28e88f384ebcb33", [:mix], [], "hexpm", "ba6f1893411c69c01b9e8e8f772062535a4cf70f3f35bcc964a324078d8c8240"},
   "dotenvy": {:hex, :dotenvy, "1.1.1", "00e318f3c51de9fafc4b48598447e386f19204dc18ca69886905bb8f8b08b667", [:mix], [], "hexpm", "c8269471b5701e9e56dc86509c1199ded2b33dce088c3471afcfef7839766d8e"},
   "file_system": {:hex, :file_system, "1.1.1", "31864f4685b0148f25bd3fbef2b1228457c0c89024ad67f7a81a3ffbc0bbad3a", [:mix], [], "hexpm", "7a15ff97dfe526aeefb090a7a9d3d03aa907e100e262a0f8f7746b78f8f87a5d"},
-  "finch": {:hex, :finch, "0.22.0", "5c48fa6f9706a78eb9036cacb67b8b996b4e66d111c543f4c29bb0f879a6806b", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b94e83c47780fc6813f746a1f1a34ee65cda42da4c5ea26a68f0acc4498e23dc"},
+  "finch": {:hex, :finch, "0.23.0", "e3f9287ac25a8832f848b144c2b57346aac65b205e2e0629a52adfe6507fd837", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "80e58d3f936f57e3fdf404f83a3642897ae6d9fb642934e46da4d8fe761b99d5"},
   "floki": {:hex, :floki, "0.38.1", "f002ccac94b3bcb21d40d9b34cc2cc9fd88a8311879120330075b5dde657ebee", [:mix], [], "hexpm", "e744bf0db7ee34b2c8b62767f04071107af0516a81144b9a2f73fe0494200e5b"},
-  "glob_ex": {:hex, :glob_ex, "0.1.11", "cb50d3f1ef53f6ca04d6252c7fde09fd7a1cf63387714fe96f340a1349e62c93", [:mix], [], "hexpm", "342729363056e3145e61766b416769984c329e4378f1d558b63e341020525de4"},
-  "hex_solver": {:hex, :hex_solver, "0.2.3", "0d2ee20fbceb251d573f03ef34852e325529c2874ab66d1b576384021318996c", [:mix], [], "hexpm", "9daeae2ea6b8ad3dc7f51a10484f6bc1d0f705c31063383830a7167ab93b887b"},
-  "hpax": {:hex, :hpax, "1.0.3", "ed67ef51ad4df91e75cc6a1494f851850c0bd98ebc0be6e81b026e765ee535aa", [:mix], [], "hexpm", "8eab6e1cfa8d5918c2ce4ba43588e894af35dbd8e91e6e55c817bca5847df34a"},
+  "glob_ex": {:hex, :glob_ex, "0.1.12", "7b2d9369c20e2697efcfd185d13d6e84c94cd3bfd2730fbde613141c2e015c00", [:mix], [], "hexpm", "2e2fac83f113514434c7eaf267b4c38af2f91766f1cab2c5db7053b7fc1ee0bb"},
+  "hex_solver": {:hex, :hex_solver, "0.3.0", "81e7659ad6caba1f856d89fc7ca52f88e8eb4f801deedcdce215f9006d706d1d", [:mix], [], "hexpm", "8a04c8ef0df25ca1f5e4d7d5f32833fac569f5c6442f05e216ee33615593e64d"},
+  "hpax": {:hex, :hpax, "1.0.4", "777de5d433b0fbdc7c418159c8055910faa8047ffdb3d6b31098d2a46cd7685c", [:mix], [], "hexpm", "afc7cb142ebcc2d01ce7816190b98ce5dd49e799111b24249f3443d730f377ca"},
   "jason": {:hex, :jason, "1.4.5", "2e3a008590b0b8d7388c20293e9dcc9cf3e5d642fd2a114e4cbbb52e595d940a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b0c823996102bcd0239b3c2444eb00409b72f6a140c1950bc8b457d836b30684"},
+  "json_codec": {:hex, :json_codec, "0.2.5", "4463d9db729ba994c356a0598b9a88ec0956a77e7ab778318d128b43db665faa", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:json_spec, "~> 1.2", [hex: :json_spec, repo: "hexpm", optional: false]}], "hexpm", "b32f189249cda0954a5fb6f4aab720444b5f3f81272869ce90098eea2418d465"},
+  "json_spec": {:hex, :json_spec, "1.2.0", "c67f73cdc4166e955b2f1095d3f44dd78c197337038f1a5301fb526b6c87ab04", [:mix], [], "hexpm", "3639961babad7d6bc45f3a2d96a49c18ec70614761bb84ce58b64e9fad9354de"},
   "mime": {:hex, :mime, "2.0.7", "b8d739037be7cd402aee1ba0306edfdef982687ee7e9859bee6198c1e7e2f128", [:mix], [], "hexpm", "6171188e399ee16023ffc5b76ce445eb6d9672e2e241d2df6050f3c771e80ccd"},
-  "mint": {:hex, :mint, "1.8.0", "b964eaf4416f2dee2ba88968d52239fca5621b0402b9c95f55a08eb9d74803e9", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "f3c572c11355eccf00f22275e9b42463bc17bd28db13be1e28f8e0bb4adbc849"},
-  "mint_web_socket": {:hex, :mint_web_socket, "1.0.5", "60354efeb49b1eccf95dfb75f55b08d692e211970fe735a5eb3188b328be2a90", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "04b35663448fc758f3356cce4d6ac067ca418bbafe6972a3805df984b5f12e61"},
+  "mint": {:hex, :mint, "1.10.0", "85af3353bfc504f5bdfe494bd92b8490f87a306dc659ee1ad0af435107e898dc", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "8b16fb72aaa7531d206a1f05e4cc85509ba531ccec7a17a22736c9c95cbb24d1"},
+  "mint_web_socket": {:hex, :mint_web_socket, "1.0.6", "5ffcf350df5b90f2d7a04adf877165228804993714592512374218d4679e325a", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "0c360e9012413f1c115a63532601eb5d63731aab7010949178769760686c1698"},
   "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.2", "8efba0122db06df95bfaa78f791344a89352ba04baedd3849593bfce4d0dc1c6", [:mix], [], "hexpm", "4b21398942dda052b403bbe1da991ccd03a053668d147d53fb8c4e0efe09c973"},
   "nimble_pool": {:hex, :nimble_pool, "1.1.0", "bf9c29fbdcba3564a8b800d1eeb5a3c58f36e1e11d7b7fb2e084a643f645f06b", [:mix], [], "hexpm", "af2e4e6b34197db81f7aad230c1118eac993acc0dae6bc83bac0126d4ae0813a"},
-  "npm": {:hex, :npm, "0.7.4", "a8cc2e760a30789e6b590257cfae9384fd1de470dab8ef62a7b35859587f34b7", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "ee265d380c19dbb9d1bba50458e1938711569a195423e6cfbf9ef7c3b8d7658a"},
+  "npm": {:hex, :npm, "0.7.6", "de8ca3dd26a40fac7ab8a17680088b8d55bab0e0294be9770b029c276361482f", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "e0a1ce77e3e49ec108e095aba133bd315e86da298dba26b142a105972141d9ef"},
   "npm_semver": {:hex, :npm_semver, "0.1.0", "3ab2c2a151d8c87c364209b2ca1a4fd2ab98507ed61afbd1ea12c1826e67200a", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "77afbc4c523c19a572325190bc4c968ec027e1c6ef8538bcddacf835966072fa"},
-  "oxc": {:hex, :oxc, "0.15.1", "d4b1770f26cd80b84ac592a54db38c50af92c98ce480be2ae1badbc0eccd614e", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "1008f80d04b961f5f262a0aec99781f3a73e5c4c7fc969f4336ca96f653c7d58"},
-  "oxide_ex": {:hex, :oxide_ex, "0.2.1", "ff0e1c03f58c151ca87e3b11847801a751853894fd926910f459ef5918cc655a", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "25bebc0d30362dead560e815a1380c266d018924a71a548ea2b1582f8dcd77bb"},
-  "phoenix": {:hex, :phoenix, "1.8.5", "919db335247e6d4891764dc3063415b0d2457641c5f9b3751b5df03d8e20bbcf", [:mix], [{:bandit, "~> 1.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.7", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5.3", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "83b2bb125127e02e9f475c8e3e92736325b5b01b0b9b05407bcb4083b7a32485"},
+  "oxc": {:hex, :oxc, "0.17.8", "e4c50ee0c0ce09107016b5153132b3d98421665355189b531c78ae4603047853", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "590fddfadbf843d6ab94e0f04a0e769a38358a23140728095da476c8c81f4df1"},
+  "oxide_ex": {:hex, :oxide_ex, "0.2.2", "063e0d2899e81632b7efc7849eb1dd89a7a623290a075c446b43bef14cf5795e", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "577a2fbd97c46904a31143bb700cdb374105085cfd1f7605416bb6c012cb7f60"},
+  "phoenix": {:hex, :phoenix, "1.8.14", "9279cbbcd755ac8d5f42d206915e7df13b9ab49096b98114f1c99ff908e5b42e", [:mix], [{:bandit, "~> 1.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.7", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 2.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "2782ff375824b2b5e41561fbae4764ee7b875af6898483bca49f24a9d1e37816"},
   "phoenix_html": {:hex, :phoenix_html, "4.3.0", "d3577a5df4b6954cd7890c84d955c470b5310bb49647f0a114a6eeecc850f7ad", [:mix], [], "hexpm", "3eaa290a78bab0f075f791a46a981bbe769d94bc776869f4f3063a14f30497ad"},
   "phoenix_live_reload": {:hex, :phoenix_live_reload, "1.6.2", "b18b0773a1ba77f28c52decbb0f10fd1ac4d3ae5b8632399bbf6986e3b665f62", [:mix], [{:file_system, "~> 0.2.10 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:phoenix, "~> 1.4", [hex: :phoenix, repo: "hexpm", optional: false]}], "hexpm", "d1f89c18114c50d394721365ffb428cce24f1c13de0467ffa773e2ff4a30d5b9"},
-  "phoenix_live_view": {:hex, :phoenix_live_view, "1.1.28", "8a8e123d018025f756605a2fb02a4854f0d3cd7b207f710fef1fd5d9d72d0254", [:mix], [{:igniter, ">= 0.6.16 and < 1.0.0-0", [hex: :igniter, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:lazy_html, "~> 0.1.0", [hex: :lazy_html, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0-rc", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "24faad535b65089642c3a7d84088109dc58f49c1f1c5a978659855d643466353"},
-  "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.2.0", "ff3a5616e1bed6804de7773b92cbccfc0b0f473faf1f63d7daf1206c7aeaaa6f", [:mix], [], "hexpm", "adc313a5bf7136039f63cfd9668fde73bba0765e0614cba80c06ac9460ff3e96"},
+  "phoenix_live_view": {:hex, :phoenix_live_view, "1.1.33", "8350c8bebabfa318c9afb0970eacced9174cd72603c9be2240e99d550fcc2eed", [:mix], [{:igniter, ">= 0.6.16 and < 1.0.0-0", [hex: :igniter, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:lazy_html, "~> 0.1.0", [hex: :lazy_html, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0-rc", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "2030f7987f641a269634e021bcde9373e5dea993f9373e628a44da86b2330b6c"},
+  "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.3.0", "03916bfbc31a5121945b3cfffe5aec647a5c97fe1dc172a319b94428562359c9", [:mix], [], "hexpm", "eec7be6e9cf02e2551d389b558402d6c637cd3973796326e7ba4bb03c6b2e91d"},
   "phoenix_template": {:hex, :phoenix_template, "1.0.4", "e2092c132f3b5e5b2d49c96695342eb36d0ed514c5b252a77048d5969330d639", [:mix], [{:phoenix_html, "~> 2.14.2 or ~> 3.0 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: true]}], "hexpm", "2c0c81f0e5c6753faf5cca2f229c9709919aba34fab866d3bc05060c9c444206"},
-  "plug": {:hex, :plug, "1.19.2", "e4950525b22c6789dfb38a3f95d47171ba159da3fc5a33be9643b43d5e8adb98", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b6fce20a56af5e60fa5dfecf3f907bb98ec981be43c79a3809a499bc3d133de0"},
-  "plug_crypto": {:hex, :plug_crypto, "2.1.1", "19bda8184399cb24afa10be734f84a16ea0a2bc65054e23a62bb10f06bc89491", [:mix], [], "hexpm", "6470bce6ffe41c8bd497612ffde1a7e4af67f36a15eea5f921af71cf3e11247c"},
-  "quickbeam": {:hex, :quickbeam, "0.10.15", "8622e090ba8476b4a7c008ddb75c741e770f45e64f9fc30c43b02694213a8605", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.4", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.15.0", [hex: :oxc, repo: "hexpm", optional: false]}, {:zigler, "~> 0.15.2", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.4", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "2da3750f1e99ae1d97b6e99a2b8ea86ba48c49c568d8f711d65d342430dcfb86"},
-  "req": {:hex, :req, "0.5.18", "48e6431cb4135e8a7815e745177485369a9b4a9924d5fe68ca00eb09ceaed1ef", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.21.0 or ~> 0.22.0", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "fa03812c440a9754bf34355e0c5d4f3ed316458db62e3284b7a352ef8dc0b996"},
+  "plug": {:hex, :plug, "1.20.3", "56c480c633ec2ce10140e236e15233bf576e1d323887d7c96711bd02ab5160db", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "be266aee1b8536ef6409d58cf39a3121319f0ec47cfa1b24024485aa0e76ad76"},
+  "plug_crypto": {:hex, :plug_crypto, "2.2.0", "144014737daaf485407f5ed77daeaad74d651b216a28c87543f8cc7043f8efc8", [:mix], [], "hexpm", "83a95744ab1c75876542b6fab135fcc176280e0f301a111c1f757fddcec95d2c"},
+  "quickbeam": {:hex, :quickbeam, "0.11.1", "55e7700b2a16c8df246402f8400908222e906f3b463af4ac8706f748d83b66db", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:mint, "~> 1.10", [hex: :mint, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.6", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.17.8", [hex: :oxc, repo: "hexpm", optional: false]}, {:varint, "~> 1.6", [hex: :varint, repo: "hexpm", optional: false]}, {:zigler, "~> 0.16.0", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.6", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "6c0240b9d016bbc174319ef004e81f2893ae2e77939d6b9b87c5542b344d0b87"},
+  "req": {:hex, :req, "0.7.4", "23e9ffec17de032a46a4b15ed65c09793893bf4a7c680f4bbf6227fce6bdf74d", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:finch, "~> 0.21", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "4b192d63253e8dcc6221ef992ea9ebef7d3555166e8423aa5b553e86bc3c69a2"},
   "rustler_precompiled": {:hex, :rustler_precompiled, "0.9.0", "3a052eda09f3d2436364645cc1f13279cf95db310eb0c17b0d8f25484b233aa0", [:mix], [{:rustler, "~> 0.23", [hex: :rustler, repo: "hexpm", optional: true]}], "hexpm", "471d97315bd3bf7b64623418b3693eedd8e47de3d1cb79a0ac8f9da7d770d94c"},
   "telemetry": {:hex, :telemetry, "1.4.2", "a0cb522801dffb1c49fe6e30561badffc7b6d0e180db1300df759faa22062855", [:rebar3], [], "hexpm", "928f6495066506077862c0d1646609eed891a4326bee3126ba54b60af61febb1"},
   "telemetry_metrics": {:hex, :telemetry_metrics, "1.1.0", "5bd5f3b5637e0abea0426b947e3ce5dd304f8b3bc6617039e2b5a008adc02f8f", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "e7b79e8ddfde70adb6db8a6623d1778ec66401f366e9a8f5dd0955c56bc8ce67"},
   "telemetry_poller": {:hex, :telemetry_poller, "1.3.0", "d5c46420126b5ac2d72bc6580fb4f537d35e851cc0f8dbd571acf6d6e10f5ec7", [:rebar3], [{:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "51f18bed7128544a50f75897db9974436ea9bfba560420b646af27a9a9b35211"},
-  "thousand_island": {:hex, :thousand_island, "1.4.3", "2158209580f633be38d43ec4e3ce0a01079592b9657afff9080d5d8ca149a3af", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "6e4ce09b0fd761a58594d02814d40f77daff460c48a7354a15ab353bb998ea0b"},
-  "vize": {:hex, :vize, "0.11.1", "eda811711b1663e548936b44ede72eac9bad1efdc1ff24be7ae86ea3b03541d2", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "9d53506c28c8c2a1947322d23fcb95c20e8c4d9ddb2e33b10c794e497ee55c5a"},
+  "thousand_island": {:hex, :thousand_island, "1.5.0", "f50a213cac97262b6d5ebb85745aa2c00fec1413191e6e66834788d45425cecb", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "708923d40523e43cf99041ab37a0d4b0ec426ac6438fa3716ab23d919eaeb412"},
+  "varint": {:hex, :varint, "1.6.0", "7bced828599b2eb84491a9f067f8a5a67fc35a946d3b7582278083c7fd434b00", [:mix], [], "hexpm", "2b4f4a20650aeebe993a70b03bb99571bcbddc27c361322c28b586d8a772ce4e"},
+  "vize": {:hex, :vize, "0.14.2", "4baf40c18e00963ce802c03ebb664feaccd8558d7ec62aa43fb07ad8485d0208", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "8336744616bc27ce4edc7448cda6f0b8a481cbec9035d3c4d6bf3229be91386d"},
   "websock": {:hex, :websock, "0.5.3", "2f69a6ebe810328555b6fe5c831a851f485e303a7c8ce6c5f675abeb20ebdadc", [:mix], [], "hexpm", "6105453d7fac22c712ad66fab1d45abdf049868f253cf719b625151460b8b453"},
-  "websock_adapter": {:hex, :websock_adapter, "0.5.9", "43dc3ba6d89ef5dec5b1d0a39698436a1e856d000d84bf31a3149862b01a287f", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "5534d5c9adad3c18a0f58a9371220d75a803bf0b9a3d87e6fe072faaeed76a08"},
-  "zigler_precompiled": {:hex, :zigler_precompiled, "0.1.4", "20a166584b94d860a983ef39c93cb0a9ce40c95c48555fc3cb6532c405558410", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:zigler, "~> 0.13", [hex: :zigler, repo: "hexpm", optional: true]}], "hexpm", "9cd6998a8ddf2f03ded1b6ebc9acb9bfa5e23b614f047583c76c01bf66c4640e"},
+  "websock_adapter": {:hex, :websock_adapter, "0.6.0", "73db5ab8aaefd1a876a97ce3e6afc96562625de69ef17a4e04426e034849d0b8", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "50021a85bce8f203b086705d9e0c5415e2c7eb05d319111b0428fe71f9934617"},
+  "zigler_precompiled": {:hex, :zigler_precompiled, "0.1.6", "1c5c889ff30164eb340e599ae987b6c51c3ba0654117ec7a68a6b83d4df39310", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:zigler, "~> 0.13", [hex: :zigler, repo: "hexpm", optional: true]}], "hexpm", "5754d342533b2fb8e767c0ef216ee13c928e17f317cac7d6a01a0972ba68ce4a"},
 }
diff --git a/guides/cheatsheets/cli.cheatmd b/guides/cheatsheets/cli.cheatmd
index 5510358..cdd8e9e 100644
--- a/guides/cheatsheets/cli.cheatmd
+++ b/guides/cheatsheets/cli.cheatmd
@@ -15,7 +15,7 @@ Set up Volt in a Phoenix project.
 
 ```bash
 mix volt.build
-mix volt.build --tailwind --no-hash
+mix volt.build --tailwind
 ```
 
 Build production assets.
diff --git a/guides/cheatsheets/configuration.cheatmd b/guides/cheatsheets/configuration.cheatmd
index 1393be6..4b95383 100644
--- a/guides/cheatsheets/configuration.cheatmd
+++ b/guides/cheatsheets/configuration.cheatmd
@@ -121,7 +121,7 @@ Prefix or list of prefixes exposed through `import.meta.env`.
 config :volt, external: ~w(phoenix phoenix_html)
 ```
 
-Exclude packages from the bundle.
+Exclude packages from the bundle. IIFE output reads them from globals; `:esm` and `:cjs` keep the imports.
 
 ### Aliases
 
@@ -240,6 +240,22 @@ config :volt, :server, watch_dirs: ["lib/", "assets/"]
 
 Additional directories to watch for Tailwind rebuilds. The asset root is watched automatically.
 
+### Watch Ignored
+
+```elixir
+config :volt, :server, watch_ignored: ["**/.generated/**"]
+```
+
+GlobEx patterns excluded from watcher events. Patterns are relative to each watched root.
+
+### Morph
+
+```elixir
+config :volt, :server, morph: [preserve: "[data-island]"]
+```
+
+Patch changed pages in place instead of reloading them. `:preserve` selects elements owned by client code.
+
 ### Automatic Watcher
 
 ```elixir
@@ -251,34 +267,36 @@ The dev-server Plug starts a supervised watcher on the first request. Set this t
 ## Formatting Options
 {: .col-2}
 
+Set under the `:volt` key of `.formatter.exs`.
+
 ### Semi
 
 ```elixir
-config :volt, :format, semi: false
+[volt: [semi: false]]
 ```
 
 ### Single Quote
 
 ```elixir
-config :volt, :format, single_quote: true
+[volt: [single_quote: true]]
 ```
 
 ### Print Width
 
 ```elixir
-config :volt, :format, print_width: 100
+[volt: [print_width: 100]]
 ```
 
 ### Trailing Comma
 
 ```elixir
-config :volt, :format, trailing_comma: :none
+[volt: [trailing_comma: :none]]
 ```
 
 ### Arrow Parens
 
 ```elixir
-config :volt, :format, arrow_parens: :always
+[volt: [arrow_parens: :always]]
 ```
 
 ## Lint Options
@@ -287,7 +305,7 @@ config :volt, :format, arrow_parens: :always
 ### Plugins
 
 ```elixir
-config :volt, :lint, plugins: [:typescript, :react]
+config :volt, :lint, plugins: ["typescript", "react"]
 ```
 
 ### Rules
diff --git a/guides/deployment/production-builds.md b/guides/deployment/production-builds.md
index df1cd6c..4a370c7 100644
--- a/guides/deployment/production-builds.md
+++ b/guides/deployment/production-builds.md
@@ -5,17 +5,56 @@ mix volt.build
 ```
 
 ```text
-Building Tailwind CSS...
-  app-1a2b3c4d.css  23.9 KB
-Built Tailwind in 43ms
-Building "assets/js/app.ts"...
+Building ["assets/js/app.ts"]...
   app-5e6f7a8b.js  128.4 KB
+  app-1a2b3c4d.css  23.9 KB
   manifest.json  2 entries
-Built in 15ms
+Built in 58ms
 ```
 
 Reads configuration from `config :volt`. CLI flags override config values.
 
+## Publication guarantees
+
+Volt prepares and validates compiled assets and public files before publication.
+It stages file contents beside the destination, installs assets, then installs the
+manifest last. Compilation, validation, and staging failures leave previous output
+untouched. Ordinary failures clean up staging files.
+
+Publication is **not a whole-directory transaction**. An installation failure may
+leave some new assets in place; unhashed URLs can then expose a mixed generation.
+An error is returned and later files are not installed. Existing unrelated files
+are preserved. Replacement behavior depends on the host filesystem; crash durability
+and cross-platform atomic replacement are not guaranteed.
+
+Publications to the same expanded destination are serialized within one BEAM node.
+This does not coordinate separate OS processes, symlink aliases, overlapping output
+roots, or build preparation order. Deployments needing an atomic site switch should
+publish to a fresh release directory and switch releases at the deployment layer.
+
+## Publication root and asset directory
+
+For `Volt.build/1`, `outdir` is the publication root: public files and the manifest
+are placed there. `assets_dir` is a relative subdirectory for compiled output
+(default: `""`, preserving Volt's existing output locations). It applies equally
+to flat and split layouts. For example, `outdir: "dist", assets_dir: "assets"`
+places public files in `dist/` and compiled output under `dist/assets/`.
+`asset_url_prefix` identifies the publication root's browser URL; the asset directory
+and layout suffixes are appended when generating URLs.
+
+The released lower-level `Volt.Builder.build/1` retains its asset-directory semantics:
+its `outdir` contains compiled files and public files go to the parent. This is a
+boundary adapter, not another independently configurable output root.
+
+## Output layout
+
+`Volt.build/1` accepts `output_layout: :split` (the default) or `:flat`.
+Split builds put module-graph output in `js/` and Tailwind output in `css/`.
+Flat builds emit both into the asset directory (`outdir` when `assets_dir` is empty).
+Both layouts write one root `manifest.json`; emitted file paths and asset URLs
+are calculated for the selected layout before writing, never relocated afterward.
+Conflicting manifest identities fail the build instead of silently replacing entries.
+
 ## What production builds do
 
 Production builds run the same framework/plugin compilation pipeline as the dev server, then apply build-only graph and output steps:
@@ -25,7 +64,7 @@ Production builds run the same framework/plugin compilation pipeline as the dev
 - rewrites relative CSS `url(...)` asset references through the asset pipeline
 - copies JavaScript- and CSS-referenced assets with content hashes
 - tree-shakes, minifies, and optionally code-splits JavaScript
-- writes a manifest that Phoenix can use for digested asset paths and chunk preload metadata
+- writes one manifest at `priv/static/assets/manifest.json` for scripts, styles, emitted assets, and chunk preload metadata
 - optionally copies a Vite-style public directory to the static root without transforming files
 
 ## Public files in Phoenix apps
@@ -97,16 +136,52 @@ config :volt, external: ~w(phoenix phoenix_html phoenix_live_view)
 
 Or per-build: `mix volt.build --external phoenix --external phoenix_html`
 
+How an external is referenced depends on the output format, as in Rollup:
+
+| Format | Output for `import { Socket } from "phoenix"` |
+| --- | --- |
+| `:iife` (default) | `const { Socket } = Phoenix;` — read from a global the page provides |
+| `:esm` | `import { Socket } from "phoenix";` — resolved by the browser, for example through an import map |
+| `:cjs` | `require("phoenix")` |
+
+For IIFE output the global name is derived from the specifier (`phoenix_html` becomes `PhoenixHtml`). Pass a map to name the globals yourself; the names are ignored for `:esm` and `:cjs`:
+
+```elixir
+config :volt, external: %{"phoenix" => "Phoenix", "vue" => "Vue"}
+```
+
+## Type Declarations for Libraries
+
+A library that ships a JavaScript client can write its type declarations with its bundle:
+
+```elixir
+"volt.build --entry priv/ts/client/my_lib.ts --format esm --name my_lib --declarations"
+```
+
+or `config :volt, declarations: true`. Each entry gets one `my_lib.d.ts` beside its bundle, without a hash, holding what the entry exports and the types those exports refer to, including types from modules that only hold types. Imports of other packages stay imports, for the consumer's `node_modules` to resolve. Point `package.json`'s `types` at the file.
+
+Declarations are emitted per module without a type checker, as `tsc --isolatedDeclarations` does, so exported declarations need explicit types: a function without a return type or a `const` whose type is inferred fails the build, naming the module and line. Set `"isolatedDeclarations": true` in `tsconfig.json` to have the editor and `mix volt.js.check --type-aware` report the same places. Two modules declaring the same name are told apart with a `$1` suffix on the one further from the entry; `import * as` and `export * as` of the library's own modules are not bundled.
+
 ## Module Preloading
 
 For code-split builds, the production manifest records static imports, dynamic imports, chunk-local CSS, and emitted assets. Use `Volt.Preload.tags/2` in your layout to preload the entry and its static chunk dependencies:
 
 ```heex
-<%= Volt.Preload.tags("priv/static/assets/js/manifest.json", "/assets/js", entry: "app.js") %>
+<%= Volt.Preload.tags("priv/static/assets/manifest.json", "/assets", entry: "app.js") %>
 ```
 
 Runtime dynamic imports are rewritten through Volt's preload helper when the async chunk has dependency chunks or CSS. The helper preloads those files before executing `import()`, avoiding extra round trips while keeping async chunks lazy.
 
+## Volt hashes and Phoenix digests
+
+Volt and Phoenix have separate responsibilities in the default deployment pipeline:
+
+1. Volt gives entries, chunks, CSS, and graph assets content-hashed filenames and records their relationships in its `manifest.json`.
+2. `phx.digest` generates Phoenix's cache manifest, compressed copies, and final static filenames.
+3. In production, `Volt.static_path/2` resolves the logical path through Volt's manifest and then passes the result through the Phoenix endpoint's `static_path/1`. With Phoenix's default configuration, the final entry URL therefore includes both hashes and `?vsn=d`.
+
+Keep Volt hashing enabled for code-split builds. Internal static and dynamic imports use Volt's filenames directly, so those hashes provide cache busting independently of Phoenix's entry URL. `--no-hash` is intended for stable-filename builds that deliberately rely on Phoenix as their only digest layer.
+
 ## Deploy Alias
 
 The installer generates an `assets.deploy` alias:
@@ -115,4 +190,4 @@ The installer generates an `assets.deploy` alias:
 "assets.deploy": ["volt.build --tailwind", "phx.digest"]
 ```
 
-This builds assets with content hashes, then generates the Phoenix digest manifest for CDN deployment.
+This builds assets with Volt content hashes, then generates the Phoenix digest manifest and compressed files for deployment. Volt is an explicit asset task rather than a Mix compiler, so a later `mix release` does not rebuild or remove this finalized output.
diff --git a/guides/features/environment-variables.md b/guides/features/environment-variables.md
index 8cef0b3..ab1c690 100644
--- a/guides/features/environment-variables.md
+++ b/guides/features/environment-variables.md
@@ -34,6 +34,19 @@ Multiple prefixes are also supported:
 config :volt, env_prefix: ["VOLT_", "PUBLIC_"]
 ```
 
+## TypeScript
+
+Volt's client types declare `import.meta.env` with `MODE`, `DEV`, `PROD`, and any other key as `string | boolean | undefined`. `mix igniter.install volt` adds them to `tsconfig.json`; to add them by hand, include `deps/volt/priv/types/client/**/*.d.ts`.
+
+Declare your own variables to get exact types and completion:
+
+```ts
+// assets/env.d.ts
+interface ImportMetaEnv {
+  readonly VOLT_API_URL: string
+}
+```
+
 ## File Loading Order
 
 Files are loaded in order, with later files overriding earlier ones:
diff --git a/guides/features/features.md b/guides/features/features.md
index 059e7d7..cbf00f4 100644
--- a/guides/features/features.md
+++ b/guides/features/features.md
@@ -128,7 +128,7 @@ Use `Volt.static_path/2` in your root layout to link to Volt-managed scripts and
 <img src={Volt.static_path(MyAppWeb.Endpoint, "/assets/images/logo.svg")} />
 ```
 
-In development, JavaScript entries return the source path served by the dev server (e.g. `/assets/js/app.ts`) and other paths are returned unchanged. In production, Volt reads `manifest.json` and returns the content-hashed path for scripts, stylesheets, and emitted image/font assets (e.g. `/assets/js/app-5e6f7a8b.js`, `/assets/css/app-2aa55585.css`, or `/assets/js/logo-a1b2c3d4.svg`).
+In development, JavaScript entries return the source path served by the dev server (e.g. `/assets/js/app.ts`) and other paths are returned unchanged. In production, Volt reads `manifest.json` to find the content-hashed script, stylesheet, or emitted asset and then passes that path through the Phoenix endpoint's `static_path/1`. After `phx.digest`, the returned URL uses Phoenix's final digest and `?vsn=d`; without a Phoenix cache manifest it remains the Volt-hashed path. See [Production Builds](../deployment/production-builds.md#volt-hashes-and-phoenix-digests).
 
 ## Multi-Entry Builds
 
@@ -176,6 +176,8 @@ Exclude packages the host page already provides:
 config :volt, external: ~w(phoenix phoenix_html phoenix_live_view)
 ```
 
+IIFE output reads externals from globals; `:esm` and `:cjs` output keeps them as imports. See [Production Builds](../deployment/production-builds.md#external-modules).
+
 ## Source Maps
 
 Production builds write `.map` files by default. Use `sourcemap: :hidden` to write maps without the URL comment (for Sentry, Datadog, etc.), or `sourcemap: false` to skip.
@@ -210,7 +212,16 @@ In development, browser `console.log`, `console.warn`, and `console.error` calls
 
 ## Error Overlay
 
-Compilation errors in development are displayed as a full-screen browser overlay with the error message. The overlay dismisses on click and clears automatically when the error is fixed.
+Compilation errors in development are displayed as a browser overlay with each error's file, line, column, and source frame. It appears on page load as well as during HMR, dismisses on click outside it, and clears automatically when the error is fixed.
+
+Add [Lumis](https://hex.pm/packages/lumis) and parser packages for your languages to highlight the source frame:
+
+```elixir
+{:lumis, "~> 0.10", only: :dev},
+{:lumis_wasm_typescript, "~> 0.26", only: :dev}
+```
+
+Without them, or for a language without an installed parser, the frame is plain text.
 
 ## Plugins
 
diff --git a/guides/features/formatting-and-linting.md b/guides/features/formatting-and-linting.md
index de1e42b..fce33a6 100644
--- a/guides/features/formatting-and-linting.md
+++ b/guides/features/formatting-and-linting.md
@@ -25,16 +25,35 @@ mix volt.js.format
 
 ### Configuration
 
+Formatter options live under the `:volt` key of `.formatter.exs`, next to the plugin:
+
+```elixir
+[
+  plugins: [Volt.Formatter],
+  inputs: ["{config,lib,test}/**/*.{ex,exs}", "assets/**/*.{js,ts,jsx,tsx}"],
+  volt: [
+    print_width: 100,
+    semi: false,
+    single_quote: true,
+    trailing_comma: :none,
+    arrow_parens: :always
+  ]
+]
+```
+
+All [oxfmt options](https://hexdocs.pm/oxc/OXC.Format.html) are supported. Without a `:volt` key, options come from `.oxfmtrc.json` or `.prettierrc.json`. `mix format`, `mix volt.js.format`, and `mix volt.js.check` all read the same options.
+
+`mix format` formats the files matched by `:inputs`. `mix volt.js.format` and `mix volt.js.check` use the build source set; `:root`, `:sources`, and `:ignore` under the `:volt` key override it for formatting only:
+
 ```elixir
-config :volt, :format,
-  print_width: 100,
-  semi: false,
-  single_quote: true,
-  trailing_comma: :none,
-  arrow_parens: :always
+[
+  volt: [semi: false, sources: ["priv/ts/**/*.ts"], ignore: ["vendor/**"]]
+]
 ```
 
-All [oxfmt options](https://hexdocs.pm/oxc/OXC.Format.html) are supported. Falls back to `.oxfmtrc.json` if no Elixir config is set.
+> #### Upgrading {: .info}
+>
+> Formatter options used to live in `config :volt, :format`. That key now only holds the build output format (`:iife`, `:esm`, or `:cjs`), and a keyword list there raises with instructions to move it.
 
 ## Linting
 
@@ -45,13 +64,17 @@ mix volt.lint
 mix volt.lint --plugin react --plugin typescript
 ```
 
-Available plugins: `react`, `typescript`, `unicorn`, `import`, `jsdoc`, `jest`, `vitest`, `jsx_a11y`, `nextjs`, `react_perf`, `promise`, `node`, `vue`, `oxc`.
+Plugin, environment, and global names are strings, as in an oxlint config file: `"react"`, `"unicorn"`, `"jsx-a11y"`, and so on. Unknown plugin names are reported as errors.
 
 ### Configuration
 
 ```elixir
 config :volt, :lint,
-  plugins: [:typescript],
+  sources: ["priv/ts/**/*.ts", "test/javascript/**/*.mjs"],
+  ignore: ["test/javascript/fixtures/**"],
+  env: ["browser", "node", "mocha"],
+  globals: %{"AppRuntime" => :readonly},
+  plugins: ["typescript"],
   rules: %{
     "no-debugger" => :deny,
     "eqeqeq" => :deny,
@@ -59,6 +82,44 @@ config :volt, :lint,
   }
 ```
 
+Lint-specific `:root`, `:sources`, and `:ignore` values override the build source set without changing which files the formatter checks. This is useful when canonical fixtures must be linted but retain their original formatting.
+
+### Per-file overrides
+
+Both `mix volt.lint` and `mix volt.js.check` resolve the same per-file settings:
+
+```elixir
+config :volt, :lint,
+  root: ".",
+  sources: ["assets/**/*.js", "scripts/**/*.js"],
+  plugins: ["typescript", "unicorn"],
+  env: ["browser"],
+  rules: %{"correctness" => :deny, "unicorn/no-null" => :deny},
+  overrides: [
+    %{
+      files: ["assets/colocated/**/*.js"],
+      rules: %{"unicorn/filename-case" => :allow}
+    },
+    %{
+      files: ["assets/js/dom.js"],
+      rules: %{"unicorn/no-null" => :allow}
+    },
+    %{
+      files: ["scripts/**/*.js"],
+      env: %{"browser" => false, "node" => true},
+      globals: %{"BuildContext" => :readonly}
+    }
+  ]
+```
+
+- `:files` is a non-empty list of globs relative to the lint root (`:root` under `:lint`, or the build root, which defaults to `assets`). Use `**/*.js` for nested files; `*.js` matches only the root level. Brace alternatives such as `**/*.{js,ts}` are supported.
+- Overrides change settings for discovered files; they do not add files or change `:sources`/`:ignore`. Already-discovered dotfiles can match override globs.
+- All matching overrides apply in declaration order. Later values win for each rule, environment or global; unrelated inherited entries remain intact. Rule severities are `:allow`, `:warn`, or `:deny`.
+- Environment lists enable names; maps can enable or disable them. Set an inherited global to `:off` to remove it, or use `:readonly`/`:writable` to set its access.
+- Override entries may be maps or keyword lists and support only `:files`, `:rules`, `:env`, and `:globals`. Plugins and custom rules remain run-wide; `mix volt.lint --plugin` retains its precedence over configured plugins.
+
+Type-aware checks group files by their effective TypeScript rules. Vue/Svelte script overrides match the original component path, not the generated virtual filename. Every group retains the complete set of extracted script sources, and diagnostics are mapped back to component paths. Environment/global overrides apply to syntax linting, not to TypeScript's project-level compiler configuration. File discovery and formatting settings are unchanged.
+
 ### Custom Rules
 
 Custom lint rules can be written in Elixir using the `OXC.Lint.Rule` behaviour — see the [oxc docs](https://hexdocs.pm/oxc/OXC.Lint.Rule.html).
@@ -80,6 +141,8 @@ mix volt.js.check --type-aware --type-check
 
 `--type-aware` also checks JavaScript-like scripts embedded in framework component files when the enabled plugin exposes them. Volt's built-in Vue and Svelte plugins expose `<script>` blocks as virtual `.js`, `.ts`, or `.tsx` modules for `tsgolint`, then map diagnostics back to the original `.vue` or `.svelte` file. Component templates are still handled by the normal syntax lint/format path; they are not passed to `tsgolint`.
 
+Imports of `.vue` files are typed by the component itself: `import Button from "./Button.vue"` gives a component whose props, emits and slots the checker knows, so `h(Button, { ... })` and `InstanceType<typeof Button>` are checked against them. No `declare module "*.vue"` shim is needed for checked files.
+
 Configure the executable when it is not on `PATH`:
 
 ```elixir
@@ -96,3 +159,5 @@ config :volt, :lint,
 Volt keeps the Oxlint-style rule shape: configure normal and type-aware rules together under `:rules`. When `--type-aware` is enabled, Volt still runs the normal syntax lint path and also invokes `tsgolint` for supported semantic TypeScript rules.
 
 Exits with non-zero status on issues.
+
+With `--type-aware`, categories also select type-aware rules from the enabled plugins. For example, `"correctness" => :deny` with `plugins: ["typescript"]` runs `typescript/no-floating-promises`. Individual rule settings override their categories, and per-file overrides apply before categories are expanded. Configurations without categories run only the type-aware rules they name. `--type-check` independently enables TypeScript compiler diagnostics.
diff --git a/guides/features/frameworks.md b/guides/features/frameworks.md
index 5beee9e..7848099 100644
--- a/guides/features/frameworks.md
+++ b/guides/features/frameworks.md
@@ -15,7 +15,7 @@ config :volt,
   sources: ["**/*.{js,ts,jsx,tsx}"],
   import_source: "react"
 
-config :volt, :lint, plugins: [:typescript, :react]
+config :volt, :lint, plugins: ["typescript", "react"]
 ```
 
 ```json
@@ -62,7 +62,7 @@ config :volt,
     ]
   ]
 
-config :volt, :lint, plugins: [:typescript, :vue]
+config :volt, :lint, plugins: ["typescript", "vue"]
 ```
 
 ```json
@@ -115,7 +115,7 @@ config :volt,
     ]
   ]
 
-config :volt, :lint, plugins: [:typescript]
+config :volt, :lint, plugins: ["typescript"]
 ```
 
 ```json
@@ -155,7 +155,7 @@ config :volt,
   sources: ["**/*.{js,ts,jsx,tsx}"],
   plugins: [Volt.Plugin.Solid]
 
-config :volt, :lint, plugins: [:typescript]
+config :volt, :lint, plugins: ["typescript"]
 ```
 
 ```json
diff --git a/guides/features/hmr.md b/guides/features/hmr.md
index b02c790..9bd5c8a 100644
--- a/guides/features/hmr.md
+++ b/guides/features/hmr.md
@@ -2,6 +2,33 @@
 
 The file watcher monitors your asset and template directories and pushes updates to the browser over a WebSocket.
 
+## Managed session ownership
+
+Choose one watcher owner. A watched `Volt.DevServer` starts a managed session;
+`mix volt.dev` also owns a managed session and preserves its file-backed CSS sink.
+Do not enable automatic Plug watching alongside a CLI watcher with different options.
+To attach a Plug to a CLI-owned session, use `watch: false` and the matching identity:
+
+```elixir
+session = Volt.Dev.session_identity(root: "assets", id: :default)
+plug Volt.DevServer, root: "assets", watch: false, session: session
+```
+
+Use the named profile as `id` when the CLI runs with a profile. Session identity is
+independent of stylesheet URL. Put Volt's development Plug **before `Plug.Static`**
+for its owned asset URLs; an earlier static plug can halt with stale generated CSS.
+Configure the same Tailwind input/URL for the host and CLI. Conflicting managed
+start configurations are rejected rather than merged. Requests encountering a
+session disappearing during lookup return a retryable 503.
+
+## Stylesheet dependency assets
+
+Relative image and font URLs resolved from project stylesheets can refer to files
+outside the asset root, including package assets. Volt serves these through
+session-scoped `/@volt/assets/` URLs. Only files resolved by the stylesheet pipeline
+are registered; the endpoint does not accept filesystem paths. Registrations end
+with the session's state generation.
+
 ## What Gets Updated
 
 | File type | Action |
@@ -9,8 +36,11 @@ The file watcher monitors your asset and template directories and pushes updates
 | `.ts`, `.tsx`, `.js`, `.jsx`, `.vue`, `.svelte`, `.css`, `.scss`, `.sass` | Recompile, push update over WebSocket |
 | `.ex`, `.heex`, `.eex` | Incremental Tailwind rebuild, CSS hot-swap |
 | `.vue` (style-only change) | CSS hot-swap, no page reload |
+| A linked package (a path dependency or `npm link`) | Bundle the package again, full page reload |
+
+Packages are served under a versioned URL that browsers cache. The version changes when a lockfile changes, so an install is picked up on the next page load, and when a package is bundled again. Packages linked from outside `node_modules` are watched; one edited inside `node_modules` is bundled again on the next source change or server start.
 
-The browser client auto-reconnects on disconnect and shows compilation errors as an overlay.
+The browser client auto-reconnects on disconnect, reloading the page when the connection returns, and shows compilation errors as an overlay. The dev server adds the client to HTML pages the app renders, so the overlay also appears when a page's scripts fail to load.
 
 ## Server-side broadcasts
 
@@ -23,20 +53,26 @@ Volt.HMR.style_update("css/app.css")
 # Ask the browser to reload the current page
 Volt.HMR.full_reload("content/posts/hello.md")
 
+# Ask open pages to check whether their HTML changed, and reload if it did
+Volt.HMR.document_update("content/posts/hello.md")
+
 # Send a custom update payload, optionally with an HMR boundary
 Volt.HMR.update("src/counter.ts", [:hmr], boundary: "/assets/counter.ts")
 
-# Show the browser error overlay
+# Show the browser error overlay, then hide it once the file is fixed
 Volt.HMR.error("content/posts/hello.md", "Invalid frontmatter")
+Volt.HMR.clear_error("content/posts/hello.md")
 ```
 
+Errors can be messages, exceptions, or `OXC.Diagnostic` maps with a location, which the overlay shows with a source frame. They stay current until cleared, so browsers that connect later see them too.
+
 Use this when an external package owns additional dependency graphs, such as pages, layouts, or content collections, while Volt serves the asset graph.
 
 `Volt.HMR.invalidate_file/1` evicts Volt's dev compilation state for a source file and marks its module-graph nodes invalidated without broadcasting. Use it before sending your own update when an external package knows a file's compiled output is stale.
 
 ## Watching extra reload directories
 
-`Volt.Watcher` can watch directories outside the asset root and request a full browser reload when files there change:
+`Volt.Watcher` can watch directories of templates and content outside the asset root. When a file there changes, open pages check whether their HTML changed and reload only if it did:
 
 ```elixir
 Volt.Watcher.start_link(
@@ -58,6 +94,88 @@ mix volt.dev --reload-dir content --reload-dir layouts
 
 This is intentionally generic: Volt does not parse those files or assign site semantics to them.
 
+### Reloading only the pages that changed
+
+A template or content file may affect any page, or none, and Volt does not know which. Each HTML page the dev server adds its client to carries an entity tag of the HTML it was rendered with. On a change, the client requests its page again with `If-None-Match`; the server renders it, answers `304 Not Modified` when the HTML is the same, and the page stays as it is. Any other answer reloads the page.
+
+So editing one blog post reloads the tab showing that post and leaves the others alone, and saving a file without changing what a page renders reloads nothing. Pages whose HTML differs on every render, such as those embedding a CSRF token, reload on every change as before.
+
+A server that adds the dev client to its pages itself opts in by following `Volt.HMR.Document`.
+
+### Updating the page in place
+
+A page that did change reloads by default. With `:morph`, the dev client patches it instead: it takes the HTML it just received and changes only the parts of the page that differ, so scroll position, focus and JavaScript state survive an edit to text or classes.
+
+```elixir
+config :volt, :server, morph: true
+```
+
+Patching cannot re-run scripts or reload stylesheets, so the client reloads the page as before when:
+
+- the scripts the page runs differ (data blocks such as `<script type="application/json">` are patched);
+- the stylesheet links or `<style>` elements differ;
+- the server answers with an error.
+
+Elements that client code owns, such as the root of a mounted component, must be left alone. Name them with a selector:
+
+```elixir
+config :volt, :server, morph: [preserve: "[data-island]"]
+```
+
+The client never touches a preserved element or what is inside it. If the attributes the server renders for one change, or preserved elements are added or removed, the page reloads.
+
+After a patch the client dispatches `volt:document-updated` on `document`, for code that attaches behaviour to elements and needs to pick up new ones:
+
+```javascript
+document.addEventListener("volt:document-updated", () => enhance(document))
+```
+
+### Letting the server compare renders
+
+By default a page finds out what changed by requesting itself again. A server that can render a page outside a request can hand that to Volt instead:
+
+```elixir
+plug Volt.DevServer, document: {MySite, :render_document, []}
+```
+
+The function is called with the page's path, followed by the listed arguments, and returns `{:ok, html}`, the HTML a request for that path is answered with, or `:error`.
+
+Each open page has its own websocket process, which lives as long as the page does. With `:document` and `:morph` set, that process keeps the HTML the server last rendered for its page. When a template or content file changes it renders the page again and compares the two renders, so each page is sent only what applies to it:
+
+- nothing, when its HTML is the same;
+- a reload, when scripts or stylesheets differ or preserved elements were added or removed;
+- otherwise the new HTML to patch, with what the server changed outside the body's contents: attributes of `<html>` and `<body>`, metadata and links in `<head>`, and the attributes of preserved elements.
+
+Because both sides of the comparison are server renders, it sees what the server changed and nothing that scripts did to the page since. An attribute a script set on `<html>`, such as a theme, is in neither render and stays. The page starts from the HTML it was served, which the dev server keeps until the page connects, so opening a page costs no extra render.
+
+For each preserved element it names, the client sets the new attributes and dispatches a cancelable `volt:element-update` event on it. The element's owner re-renders it and calls `preventDefault()`; if nothing handles the event, the page reloads.
+
+```javascript
+island.addEventListener("volt:element-update", (event) => {
+  event.preventDefault()
+  rerender(JSON.parse(island.dataset.props))
+})
+```
+
+Without `:document`, only the contents of `<body>` and the title are patched. Attributes on `<html>` and `<body>`, and the rest of `<head>`, stay as they were until the next reload.
+
+## Ignoring watcher paths
+
+Exclude generated or otherwise irrelevant files before Volt schedules compilation or HMR work:
+
+```elixir
+config :volt, :server,
+  watch_ignored: ["**/.generated/**", "vendor/cache/**"]
+```
+
+Patterns use GlobEx syntax and are resolved relative to each watched root. The same option is available from the CLI:
+
+```bash
+mix volt.dev --watch-ignore "**/.generated/**"
+```
+
+Volt ignores `.git`, `node_modules`, `test-results`, `_build`, and `deps` directories by default. Ignoring a path affects file watching only; it does not prevent the dev server from serving an explicitly requested module.
+
 ## `import.meta.hot`
 
 Each module served in dev mode includes an `import.meta.hot` object for granular HMR:
diff --git a/guides/features/plugins.md b/guides/features/plugins.md
index 3e9659e..fc4c1b4 100644
--- a/guides/features/plugins.md
+++ b/guides/features/plugins.md
@@ -276,10 +276,78 @@ js =
 ```
 
 `Volt.Priv.js!/3` reads from the OTP application's `priv` directory, binds
-`$placeholder` JavaScript literals with OXC, and emits browser JavaScript. Use `OXC.splice/3`
-directly when a placeholder represents multiple syntax nodes, such as object
-entries or function arguments. Volt uses this pattern internally for
-`import.meta.glob()` output generation.
+`$placeholder` JavaScript literals with OXC, and emits browser JavaScript.
+
+Use the `:splices` option when a placeholder represents statements, object properties,
+or array elements rather than a literal:
+
+```javascript
+// priv/templates/plugin-entry.ts
+$imports
+
+export function install() {
+  $setup
+}
+```
+
+```elixir
+Volt.Priv.render!(@templates, "plugin-entry.ts", [],
+  splices: [
+    imports: [~s|import "./runtime.js";|, ~s|import "./styles.css";|],
+    setup: "registerPlugin(); startRuntime();"
+  ]
+)
+```
+
+Splices use `OXC.splice/3`, so replacements are parsed as JavaScript syntax rather
+than inserted with textual replacement. A replacement can be an AST node, source or
+iodata containing multiple nodes, or a list of those values. `render!/4` preserves
+TypeScript for the subsequent Volt build; use `js!/4` when the caller needs compiled
+browser JavaScript immediately.
+
+### Browser code with npm packages
+
+Browser code in `priv` can import npm packages that ship with your library. List them
+in a `package.json` beside the sources, pinned to exact versions:
+
+```json
+// priv/ts/package.json
+{"private": true, "dependencies": {"lit-html": "3.3.3"}}
+```
+
+Then vendor them:
+
+```bash
+mix volt.priv.vendor priv/ts
+```
+
+`priv/ts/node_modules` keeps only the files your sources reach: the browser build of
+each imported module, its type declarations, and each package's `package.json` and
+license. Commit `package.json` and the `npm.lock` that pins the versions, but keep
+`node_modules` out of git and vendor before publishing, so the files ship in your Hex
+package and nothing is installed at runtime:
+
+```elixir
+# .gitignore: /priv/ts/node_modules/
+
+defp aliases do
+  [
+    setup: ["deps.get", "volt.priv.vendor priv/ts"],
+    # A separate process, so compiling for vendoring leaves Hex's own tasks loaded.
+    "hex.build": ["cmd mix volt.priv.vendor priv/ts", "hex.build"],
+    "hex.publish": ["cmd mix volt.priv.vendor priv/ts", "hex.publish"]
+  ]
+end
+```
+
+Pass `--update` to resolve the versions again.
+
+`Volt.Priv.bundle!/3` bundles an entry with everything it imports, including the
+vendored packages. In a git or path checkout without them, it vendors on first use:
+
+```elixir
+Volt.Priv.bundle!({:my_framework, "ts"}, "widget.ts", format: :esm)
+```
 
 ### Example: AST transform with OXC
 
@@ -494,3 +562,32 @@ end
 ```
 
 The runtime automatically installs npm packages on first use and caches the bundled entry script. Subsequent calls reuse the running QuickBEAM instance.
+
+Frameworks that bundle package-owned browser modules without executing them in
+QuickBEAM can install those dependencies directly and scope them to the framework's
+source root:
+
+```elixir
+packages =
+  Volt.NPM.install!(
+    %{"framework-runtime" => "1.2.3"},
+    lockfile: Application.app_dir(:my_framework, "priv/npm.lock")
+  )
+
+Volt.Builder.build(
+  entry: "assets/app.ts",
+  node_modules: "assets/node_modules",
+  package_scopes: [
+    {Application.app_dir(:my_framework, "priv/ts"), packages.node_modules}
+  ]
+)
+```
+
+A package-owned npm_ex lockfile pins the complete transitive graph and lets fresh
+cache installations skip registry resolution. Volt validates its version, security
+policy, direct versions, integrity metadata, and required dependency closure before
+linking packages.
+
+An import originating below the scoped source root checks the framework package
+directory first. Imports from application modules continue to resolve from the
+application's `node_modules`, so package names and versions cannot shadow one another.
diff --git a/guides/features/tailwind.md b/guides/features/tailwind.md
index d4cb881..6a6ef0a 100644
--- a/guides/features/tailwind.md
+++ b/guides/features/tailwind.md
@@ -20,6 +20,20 @@ config :volt,
 - `css` — path to your Tailwind input CSS file (with `@import "tailwindcss"`)
 - `sources` — list of `%{base, pattern}` maps defining where to scan for class names
 
+## Build Lifecycle
+
+`Volt.build/1` is the public API for complete frontend builds. It composes the configured Tailwind root with the ordinary JavaScript/CSS module graph, returns a typed `%Volt.Build.Result{}`, and writes one merged manifest at the configured asset output root. `mix volt.build` is a CLI adapter around that API.
+
+```elixir
+{:ok, result} = Volt.build()
+
+result.styles
+result.assets
+result.manifest
+```
+
+Tailwind output is isolated per profile and CSS root. Root workers retain independent Oxide scanners and generated CSS state while sharing one supervised QuickBEAM compiler runtime.
+
 ## Plugins and Config Files
 
 Tailwind `@plugin` and `@config` directives are resolved and bundled automatically:
diff --git a/guides/features/testing.md b/guides/features/testing.md
index 444162d..41fd6b0 100644
--- a/guides/features/testing.md
+++ b/guides/features/testing.md
@@ -66,6 +66,14 @@ Volt.Test.ExUnit.install(
 )
 ```
 
+By default, each JavaScript `test(...)` is registered as an individual ExUnit test. Large suites can execute once per file instead:
+
+```elixir
+Volt.Test.ExUnit.install(granularity: :file)
+```
+
+File granularity keeps file-level ExUnit reporting and JavaScript failure details while avoiding a separate bundle and runtime invocation for every test. It also tags browser-backed files with `browser_js: true`.
+
 Profile-specific configuration follows the rest of Volt:
 
 ```elixir
@@ -301,7 +309,9 @@ npm install --save-dev playwright
 npx playwright install chromium
 ```
 
-By default Volt uses `node_modules/.bin/playwright` when present, otherwise `playwright` from `PATH`. Pass PlaywrightEx supervisor options with `playwright: [...]` if your executable lives elsewhere.
+By default Volt uses `node_modules/playwright/cli.js` when present, otherwise `playwright` from `PATH`. Pass PlaywrightEx supervisor options with `playwright: [...]` if your executable lives elsewhere.
+
+A test run shares one browser, launched the first time a test needs it, and every test gets a browser context of its own, so tests do not see each other's storage, cookies or pages. The ExUnit modules Volt generates for browser tests are `async: true`. The browser runs under Volt's application, which the first browser test starts if the project has not, as with a `runtime: false` dependency.
 
 ## ExUnit integration
 
diff --git a/guides/introduction/getting-started.md b/guides/introduction/getting-started.md
index 0e8acb5..71aab04 100644
--- a/guides/introduction/getting-started.md
+++ b/guides/introduction/getting-started.md
@@ -7,10 +7,10 @@ mix igniter.install volt
 ```
 
 The installer:
-- Adds `{:volt, "~> 0.16"}` to `mix.exs`
+- Adds `{:volt, "~> 0.23"}` to `mix.exs`
 - Configures build settings in `config/config.exs`
-- Adds format and lint config to `config/config.exs`
-- Adds `Volt.Formatter` plugin to `.formatter.exs`
+- Adds lint config to `config/config.exs`
+- Adds the `Volt.Formatter` plugin and formatter options to `.formatter.exs`
 - Adds the `Volt.DevServer` plug to your endpoint
 - Configures Volt's automatic development watcher
 - Updates `assets.build` and `assets.deploy` aliases
@@ -28,7 +28,7 @@ Add Volt to your dependencies:
 
 ```elixir
 def deps do
-  [{:volt, "~> 0.16"}]
+  [{:volt, "~> 0.23"}]
 end
 ```
 
@@ -107,7 +107,8 @@ Add `Volt.Formatter` to `.formatter.exs`:
     "{mix,.formatter}.exs",
     "{config,lib,test}/**/*.{ex,exs}",
     "assets/**/*.{js,ts,jsx,tsx}"
-  ]
+  ],
+  volt: [semi: false, single_quote: true]
 ]
 ```
 
diff --git a/guides/migration/from-esbuild.md b/guides/migration/from-esbuild.md
index 2ece4c6..c532a0d 100644
--- a/guides/migration/from-esbuild.md
+++ b/guides/migration/from-esbuild.md
@@ -22,7 +22,7 @@ Remove from `mix.exs`:
 Add:
 
 ```elixir
-{:volt, "~> 0.16"}
+{:volt, "~> 0.23"}
 ```
 
 ### 2. Replace Config
diff --git a/lib/mix/tasks/volt.build.ex b/lib/mix/tasks/volt/build.ex
similarity index 68%
rename from lib/mix/tasks/volt.build.ex
rename to lib/mix/tasks/volt/build.ex
index 2d6854f..e5af25c 100644
--- a/lib/mix/tasks/volt.build.ex
+++ b/lib/mix/tasks/volt/build.ex
@@ -13,6 +13,8 @@ defmodule Mix.Tasks.Volt.Build do
   ## Options
 
     * `--entry` — entry file (repeatable, default from config or `"assets/js/app.ts"`)
+    * `--assets-dir` — relative compiled-asset directory inside the output root
+    * `--output-layout` — `flat` or `split`
     * `--outdir` — output directory (default: `"priv/static/assets"`)
     * `--public-dir` — optional Vite-style public directory copied to the static root as-is
     * `--asset-url-prefix` — public URL prefix for production asset references (default: `"/assets"`)
@@ -21,13 +23,15 @@ defmodule Mix.Tasks.Volt.Build do
     * `--sourcemap false` — skip source map generation
     * `--sourcemap hidden` — write `.map` files but omit `sourceMappingURL` comment
     * `--resolve-dir` — additional directory for bare specifier resolution (repeatable)
-    * `--external` — specifier to exclude from bundle (repeatable)
+    * `--external` — specifier to exclude from bundle (repeatable); read from a global
+      in `iife` output and kept as an import in `esm` and `cjs` output
     * `--name` — output base name (default: derived from entry filename)
     * `--no-hash` — stable filenames (no content hash)
     * `--no-code-splitting` — disable chunk splitting
     * `--no-tree-shaking` — preserve unused exports
     * `--mode` — build mode for env variables (default: `"production"`)
     * `--format` — output format: `iife`, `esm`, or `cjs` (default from config)
+    * `--declarations` — write one `.d.ts` per entry beside its bundle, for a library
     * `--tailwind` — build Tailwind CSS
     * `--tailwind-css` — custom Tailwind input CSS file
     * `--tailwind-source` — source directory for Tailwind scanning (repeatable)
@@ -44,6 +48,8 @@ defmodule Mix.Tasks.Volt.Build do
         strict: [
           entry: [:string, :keep],
           outdir: :string,
+          assets_dir: :string,
+          output_layout: :string,
           public_dir: :string,
           asset_url_prefix: :string,
           target: :string,
@@ -56,6 +62,7 @@ defmodule Mix.Tasks.Volt.Build do
           resolve_dir: [:string, :keep],
           external: [:string, :keep],
           code_splitting: :boolean,
+          declarations: :boolean,
           tree_shaking: :boolean,
           tailwind: :boolean,
           tailwind_css: :string,
@@ -74,13 +81,17 @@ defmodule Mix.Tasks.Volt.Build do
     outdir = Keyword.get(parsed, :outdir) || to_string(config.outdir)
     minify = Keyword.get(parsed, :minify, config.minify)
 
-    tailwind? =
-      Keyword.get(parsed, :tailwind) ||
-        (tailwind_config != [] and Keyword.get(parsed, :tailwind, true))
+    tailwind =
+      case Keyword.fetch(parsed, :tailwind) do
+        {:ok, false} ->
+          false
 
-    if tailwind? do
-      build_tailwind(parsed, tailwind_config, outdir, minify, config.hash, config.root)
-    end
+        {:ok, true} ->
+          if(tailwind_config == [], do: true, else: tailwind_config)
+
+        :error ->
+          if parsed[:tailwind_css] && tailwind_config == [], do: true, else: tailwind_config
+      end
 
     entries =
       case cli_entries do
@@ -102,7 +113,9 @@ defmodule Mix.Tasks.Volt.Build do
 
     opts = [
       entry: if(length(entries) == 1, do: hd(entries), else: entries),
-      outdir: Path.join(outdir, "js"),
+      outdir: outdir,
+      assets_dir: Keyword.get(parsed, :assets_dir, config.assets_dir),
+      output_layout: parse_layout(Keyword.get(parsed, :output_layout), config.output_layout),
       public_dir: Keyword.get(parsed, :public_dir) || config.public_dir,
       asset_url_prefix: Keyword.get(parsed, :asset_url_prefix) || config.asset_url_prefix,
       target: Keyword.get(parsed, :target) || to_string(config.target),
@@ -116,29 +129,41 @@ defmodule Mix.Tasks.Volt.Build do
       mode: Keyword.get(parsed, :mode) || to_string(config.mode),
       format: parse_format(Keyword.get(parsed, :format), config.format),
       code_splitting: Keyword.get(parsed, :code_splitting, config.code_splitting),
+      declarations: Keyword.get(parsed, :declarations, config.declarations),
       tree_shaking: Keyword.get(parsed, :tree_shaking, config.tree_shaking),
       chunks: config.chunks,
       env_prefix: config.env_prefix,
       import_source: config.import_source,
       module_types: config.module_types,
       root: config.root,
-      name: parsed[:name]
+      name: parsed[:name],
+      profile: profile,
+      tailwind: tailwind,
+      tailwind_css: parsed[:tailwind_css],
+      tailwind_sources: tailwind_sources(parsed, tailwind_config)
     ]
 
     opts = if opts[:name], do: opts, else: Keyword.delete(opts, :name)
 
-    build_js(opts)
+    build_all(opts)
   end
 
-  defp build_js(opts) do
+  defp parse_layout(nil, default), do: default
+  defp parse_layout("flat", _default), do: :flat
+  defp parse_layout("split", _default), do: :split
+
+  defp parse_layout(other, _default),
+    do: Mix.raise("Invalid output layout: #{inspect(other)}; expected flat or split")
+
+  defp build_all(opts) do
     Mix.shell().info("Building #{inspect(opts[:entry])}...")
 
-    {us, result} = :timer.tc(fn -> Volt.Builder.build(opts) end)
+    {us, result} = :timer.tc(fn -> Volt.build(opts) end)
     ms = div(us, 1000)
 
     case result do
-      {:ok, %{js: js, css: css, manifest: manifest} = result} ->
-        case js do
+      {:ok, %Volt.Build.Result{assets: assets, styles: styles, manifest: manifest}} ->
+        case assets.js do
           %{path: path} ->
             Mix.shell().info("  #{Path.basename(path)}  #{format_file(path)}")
 
@@ -146,14 +171,18 @@ defmodule Mix.Tasks.Volt.Build do
             :ok
         end
 
-        if chunks = result[:chunks] do
-          for chunk <- chunks, chunk.type != :entry do
-            Mix.shell().info("  #{Path.basename(chunk.path)}  #{format_file(chunk.path)}")
-          end
+        for chunk <- assets.chunks, chunk.type != :entry do
+          Mix.shell().info("  #{Path.basename(chunk.path)}  #{format_file(chunk.path)}")
+        end
+
+        for style <- styles do
+          Mix.shell().info("  #{Path.basename(style.path)}  #{format_file(style.path)}")
         end
 
-        if css do
-          Mix.shell().info("  #{Path.basename(css.path)}  #{format_file(css.path)}")
+        for declaration <- assets.declarations do
+          Mix.shell().info(
+            "  #{Path.basename(declaration.path)}  #{format_file(declaration.path)}"
+          )
         end
 
         Mix.shell().info("  manifest.json  #{map_size(manifest)} entries")
@@ -165,66 +194,10 @@ defmodule Mix.Tasks.Volt.Build do
     end
   end
 
-  defp build_tailwind(parsed, tailwind_config, outdir, minify, config_hash, root) do
-    cli_sources = Keyword.get_values(parsed, :tailwind_source)
-    hash = Keyword.get(parsed, :hash, config_hash)
-
-    sources =
-      case cli_sources do
-        [] ->
-          tailwind_config[:sources] ||
-            [
-              %{base: Volt.Paths.lib(), pattern: "**/*.{ex,heex}"},
-              %{base: Volt.Paths.assets_dir(), pattern: "**/*.{vue,ts,tsx,js,jsx}"}
-            ]
-
-        list ->
-          Enum.map(list, &%{base: &1, pattern: "**/*"})
-      end
-
-    {css_input, css_base} =
-      case Keyword.get(parsed, :tailwind_css) || tailwind_config[:css] do
-        nil -> {nil, File.cwd!()}
-        path -> {File.read!(path), Path.dirname(path)}
-      end
-
-    Mix.shell().info("Building Tailwind CSS...")
-
-    {us, result} =
-      :timer.tc(fn ->
-        with {:ok, css} <-
-               Volt.Tailwind.build(
-                 sources: sources,
-                 css: css_input,
-                 css_base: css_base,
-                 minify: false
-               ) do
-          Volt.Builder.Writer.build_style_entry(
-            "app",
-            css,
-            Path.join(outdir, "css"),
-            hash,
-            nil,
-            minify: minify,
-            root: root
-          )
-        end
-      end)
-
-    ms = div(us, 1000)
-
-    case result do
-      {:ok, %{css: %{path: path, size: size}, manifest: manifest}} ->
-        css_outdir = Path.dirname(path)
-        Volt.Builder.Writer.write_manifest(css_outdir, manifest)
-
-        Mix.shell().info("  #{Path.basename(path)}  #{Volt.Format.format_size(size)}")
-        Mix.shell().info("  manifest.json  #{map_size(manifest)} entries")
-        Mix.shell().info("Built Tailwind in #{ms}ms")
-
-      {:error, reason} ->
-        Mix.shell().error("Tailwind build failed: #{inspect(reason)}")
-        exit({:shutdown, 1})
+  defp tailwind_sources(parsed, tailwind_config) do
+    case Keyword.get_values(parsed, :tailwind_source) do
+      [] -> tailwind_config[:sources]
+      list -> Enum.map(list, &%{base: &1, pattern: "**/*"})
     end
   end
 
diff --git a/lib/mix/tasks/volt.dev.ex b/lib/mix/tasks/volt/dev.ex
similarity index 67%
rename from lib/mix/tasks/volt.dev.ex
rename to lib/mix/tasks/volt/dev.ex
index b66a777..381b4cf 100644
--- a/lib/mix/tasks/volt.dev.ex
+++ b/lib/mix/tasks/volt/dev.ex
@@ -15,6 +15,7 @@ defmodule Mix.Tasks.Volt.Dev do
     * `--root` — asset source directory (default from config or `"assets"`)
     * `--watch-dir` — additional directory to watch for Tailwind scanning (repeatable)
     * `--reload-dir` — additional directory whose changes trigger a full browser reload (repeatable)
+    * `--watch-ignore` — path or glob pattern excluded from watcher events (repeatable)
     * `--tailwind` — enable Tailwind CSS rebuilds
     * `--tailwind-css` — custom Tailwind input CSS file
     * `--tailwind-outdir` — directory to write rebuilt CSS (default: `"priv/static/assets/css"`)
@@ -22,6 +23,7 @@ defmodule Mix.Tasks.Volt.Dev do
   """
   use Mix.Task
 
+  alias Volt.Dev
   alias Volt.Config
   alias Volt.Paths
 
@@ -35,6 +37,7 @@ defmodule Mix.Tasks.Volt.Dev do
           root: :string,
           watch_dir: [:string, :keep],
           reload_dir: [:string, :keep],
+          watch_ignore: [:string, :keep],
           tailwind: :boolean,
           tailwind_css: :string,
           tailwind_outdir: :string,
@@ -50,12 +53,21 @@ defmodule Mix.Tasks.Volt.Dev do
     root = Keyword.get(parsed, :root) || to_string(config.root)
     target = Keyword.get(parsed, :target) || to_string(config.target)
 
+    tailwind_root =
+      tailwind_config
+      |> Keyword.put(:css, Keyword.get(parsed, :tailwind_css) || tailwind_config[:css])
+      |> Volt.Config.Tailwind.new()
+
     tailwind? =
-      Keyword.get(parsed, :tailwind) ||
-        (tailwind_config != [] and Keyword.get(parsed, :tailwind, true))
+      Keyword.get(
+        parsed,
+        :tailwind,
+        not is_nil(parsed[:tailwind_css]) or Volt.Config.Tailwind.enabled?(tailwind_config)
+      )
 
     cli_watch_dirs = Keyword.get_values(parsed, :watch_dir)
     cli_reload_dirs = Keyword.get_values(parsed, :reload_dir)
+    cli_watch_ignored = Keyword.get_values(parsed, :watch_ignore)
 
     watch_dirs =
       case cli_watch_dirs do
@@ -69,25 +81,33 @@ defmodule Mix.Tasks.Volt.Dev do
         list -> list
       end
 
-    watch_dirs = if tailwind? and watch_dirs == [], do: [Paths.lib()], else: watch_dirs
+    watch_ignored =
+      case cli_watch_ignored do
+        [] -> server_config.watch_ignored
+        list -> list
+      end
 
-    tailwind_css = Keyword.get(parsed, :tailwind_css) || tailwind_config[:css]
+    watch_dirs = if tailwind? and watch_dirs == [], do: [Paths.lib()], else: watch_dirs
 
-    if tailwind? do
-      initial_build(tailwind_config, tailwind_css, parsed)
-    end
+    tailwind_css = tailwind_root.css
 
     opts = [
+      id: profile || :default,
       root: root,
       watch_dirs: watch_dirs,
       reload_dirs: reload_dirs,
+      watch_ignored: watch_ignored,
+      tailwind_key: tailwind_key(profile, tailwind_root),
       tailwind: tailwind?,
       tailwind_css: tailwind_css,
-      tailwind_outdir: Keyword.get(parsed, :tailwind_outdir, Paths.static_css()),
+      tailwind_name: tailwind_root.name,
+      tailwind_sources: tailwind_root.sources,
+      tailwind_url: tailwind_root.dev_url,
+      tailwind_sink: Keyword.get(parsed, :tailwind_outdir, Paths.static_css()),
       target: target
     ]
 
-    {:ok, _pid} = Volt.Watcher.start_link(opts)
+    {:ok, _pid} = Dev.start(opts)
 
     Mix.shell().info("[Volt] Watching #{opts[:root]}...")
 
@@ -99,40 +119,24 @@ defmodule Mix.Tasks.Volt.Dev do
       Mix.shell().info("[Volt] Full reload dirs: #{Enum.join(reload_dirs, ", ")}")
     end
 
-    unless iex_running?() do
-      Process.sleep(:infinity)
+    if watch_ignored != [] do
+      Mix.shell().info("[Volt] Ignored watcher paths: #{Enum.join(watch_ignored, ", ")}")
     end
-  end
 
-  defp initial_build(tailwind_config, tailwind_css, parsed) do
-    sources =
-      tailwind_config[:sources] ||
-        [
-          %{base: Paths.lib(), pattern: "**/*.{ex,heex,eex}"},
-          %{base: Paths.assets_dir(), pattern: "**/*.{vue,ts,tsx,js,jsx}"}
-        ]
+    unless iex_running?() do
+      session = Dev.session_identity(opts)
 
-    {css_input, css_base} =
-      case tailwind_css do
-        nil -> {nil, File.cwd!()}
-        path -> {File.read!(path), Path.dirname(path)}
+      try do
+        Process.sleep(:infinity)
+      after
+        Dev.stop(session)
       end
-
-    case Volt.Tailwind.build(sources: sources, css: css_input, css_base: css_base) do
-      {:ok, css} ->
-        outdir = Keyword.get(parsed, :tailwind_outdir, Paths.static_css())
-        File.mkdir_p!(outdir)
-        File.write!(Path.join(outdir, "app.css"), css)
-
-        Mix.shell().info(
-          "[Volt] Initial Tailwind build: #{Volt.Format.format_size(byte_size(css))}"
-        )
-
-      {:error, reason} ->
-        Mix.shell().error("[Volt] Tailwind build failed: #{inspect(reason)}")
     end
   end
 
+  defp tailwind_key(profile, root),
+    do: {:profile, profile || :default, root.css || root.name}
+
   defp parse_profile(args), do: Volt.Config.Profile.from_args(args)
 
   @dialyzer {:nowarn_function, iex_running?: 0}
diff --git a/lib/mix/tasks/volt.install.ex b/lib/mix/tasks/volt/install.ex
similarity index 72%
rename from lib/mix/tasks/volt.install.ex
rename to lib/mix/tasks/volt/install.ex
index 9abc231..5d3e252 100644
--- a/lib/mix/tasks/volt.install.ex
+++ b/lib/mix/tasks/volt/install.ex
@@ -17,10 +17,21 @@ if Code.ensure_loaded?(Igniter) do
     2. Remove `config :esbuild` and `config :tailwind` blocks
     3. Update `assets.setup`, `assets.build`, and `assets.deploy` aliases
     4. Add Volt build config to `config/config.exs`
-    5. Add format and lint config to `config/config.exs`
-    6. Add `Volt.Formatter` plugin to `.formatter.exs`
+    5. Add lint config to `config/config.exs`
+    6. Add `Volt.Formatter` plugin and formatter options to `.formatter.exs`
     7. Add `Volt.DevServer` plug to your endpoint
     8. Configure the automatic Volt watcher in `config/dev.exs`
+    9. Wire Volt client types into TypeScript configuration
+
+    The installer checks `tsconfig.json`, `assets/tsconfig.json`, and
+    `assets/js/tsconfig.json`. Ordinary JSON configurations retain their settings
+    and receive explicit declaration files, even when dependencies are excluded.
+    When none exists, the installer creates a root configuration from a template.
+
+    JSONC and configurations using `extends` or project references are left
+    unchanged with guidance to include `deps/volt/priv/types/client/**/*.d.ts`
+    (relative to the browser configuration). No local `ImportMeta` declaration
+    is needed.
     """
 
     use Igniter.Mix.Task
@@ -33,6 +44,7 @@ if Code.ensure_loaded?(Igniter) do
     alias Igniter.Project.Config, as: ProjectConfig
     alias Igniter.Project.Deps, as: ProjectDeps
     alias Igniter.Project.Formatter, as: ProjectFormatter
+    alias Sourceror.Zipper
     alias Volt.Paths
     alias Igniter.Project.TaskAliases
 
@@ -55,13 +67,72 @@ if Code.ensure_loaded?(Igniter) do
       |> remove_old_watchers(app_name, endpoint)
       |> update_aliases()
       |> add_volt_config()
-      |> add_format_config()
       |> add_lint_config()
       |> add_formatter_plugin()
+      |> add_format_config()
+      |> add_typescript_config()
       |> add_dev_config(app_name, endpoint)
       |> add_dev_server_plug()
     end
 
+    defp add_typescript_config(igniter) do
+      configs = [
+        {"tsconfig.json", "deps"},
+        {"assets/tsconfig.json", "../deps"},
+        {"assets/js/tsconfig.json", "../../deps"}
+      ]
+
+      existing = Enum.filter(configs, fn {path, _} -> Igniter.exists?(igniter, path) end)
+
+      case existing do
+        [] ->
+          template = Application.app_dir(:volt, "priv/templates/volt.install/tsconfig.json.eex")
+          Igniter.copy_template(igniter, template, "tsconfig.json", [])
+
+        paths ->
+          Enum.reduce(paths, igniter, fn {path, deps}, igniter ->
+            Igniter.update_file(igniter, path, &include_client_types(&1, deps))
+          end)
+      end
+    end
+
+    defp include_client_types(source, deps) do
+      with {:ok, config} when is_map(config) <- Jason.decode(Rewrite.Source.get(source, :content)),
+           false <- Map.has_key?(config, "extends") or Map.has_key?(config, "references"),
+           files when is_list(files) <- Map.get(config, "files", []),
+           true <- Enum.all?(files, &is_binary/1) do
+        types = [
+          "#{deps}/volt/priv/types/client/env.d.ts",
+          "#{deps}/volt/priv/types/client/hmr.d.ts",
+          "#{deps}/volt/priv/types/client/preload.d.ts",
+          "#{deps}/volt/priv/types/client/styles.d.ts"
+        ]
+
+        updated =
+          config
+          |> preserve_default_include()
+          |> Map.put("files", Enum.uniq(files ++ types))
+
+        if updated == config do
+          source
+        else
+          Rewrite.Source.update(source, :content, Jason.encode!(updated, pretty: true) <> "\n")
+        end
+      else
+        _ ->
+          {:warning,
+           "Volt left #{source.path} unchanged: JSONC, inherited and referenced projects require " <>
+             "manual configuration. Include #{deps}/volt/priv/types/client/**/*.d.ts in the browser " <>
+             "project, ensuring it is not excluded. No application-local ImportMeta declaration is needed."}
+      end
+    end
+
+    defp preserve_default_include(config) do
+      if Map.has_key?(config, "files") or Map.has_key?(config, "include"),
+        do: config,
+        else: Map.put(config, "include", ["**/*"])
+    end
+
     # ── Remove old tooling ──
 
     defp remove_old_deps(igniter) do
@@ -166,19 +237,27 @@ if Code.ensure_loaded?(Igniter) do
           opts
         )
 
-      code =
-        format_kw
-        |> Enum.map(fn {key, value} -> [to_string(key), ": ", inspect(value)] end)
-        |> Enum.intersperse(",\n  ")
-        |> IO.iodata_to_binary()
-
-      ProjectConfig.configure(
-        igniter,
-        "config.exs",
-        :volt,
-        [:format],
-        {:code, Sourceror.parse_string!("[\n  #{code}\n]")}
-      )
+      # Runs after `add_formatter_plugin/1`, which creates `.formatter.exs`.
+      Igniter.update_elixir_file(igniter, ".formatter.exs", fn zipper ->
+        zipper
+        |> Zipper.down()
+        |> Zipper.rightmost()
+        |> CodeKeyword.put_in_keyword([:volt], format_kw, &{:ok, &1})
+        |> case do
+          {:ok, zipper} ->
+            {:ok, zipper}
+
+          _ ->
+            {:warning,
+             """
+             Could not add Volt formatter options to `.formatter.exs`.
+
+             Please add them manually, i.e
+
+                 volt: #{inspect(format_kw)}
+             """}
+        end
+      end)
     end
 
     defp add_lint_config(igniter) do
@@ -190,7 +269,7 @@ if Code.ensure_loaded?(Igniter) do
         {:code,
          Sourceror.parse_string!("""
          [
-           plugins: [:typescript, :import, :unicorn],
+           plugins: ["typescript", "import", "unicorn"],
            rules: %{
              "no-debugger" => :deny,
              "no-unused-vars" => :warn,
diff --git a/lib/mix/tasks/volt.js.check.ex b/lib/mix/tasks/volt/js/check.ex
similarity index 78%
rename from lib/mix/tasks/volt.js.check.ex
rename to lib/mix/tasks/volt/js/check.ex
index e78d7a1..8b0bbd5 100644
--- a/lib/mix/tasks/volt.js.check.ex
+++ b/lib/mix/tasks/volt/js/check.ex
@@ -9,7 +9,7 @@ defmodule Mix.Tasks.Volt.Js.Check do
       mix volt.js.check
       mix volt.js.check --type-aware --type-check
 
-  Reads format options from `config :volt, :format` (falls back to `.oxfmtrc.json`).
+  Reads format options from the `:volt` key of `.formatter.exs` (falls back to `.oxfmtrc.json`).
   Lint settings come from `config :volt, :lint`.
   File discovery uses `config :volt, sources:` and `ignore:`.
 
@@ -22,8 +22,8 @@ defmodule Mix.Tasks.Volt.Js.Check do
     Mix.Task.run("app.config")
 
     opts = parse_args!(args)
-    format_files = Volt.JS.Helpers.discover_format_files()
-    lint_files = Volt.JS.Helpers.discover_files()
+    format_files = Volt.JS.Discovery.format_files()
+    lint_files = Volt.JS.Discovery.files(tool: :lint)
 
     if format_files == [] and lint_files == [] do
       Mix.shell().info("No files found")
@@ -45,9 +45,7 @@ defmodule Mix.Tasks.Volt.Js.Check do
         Mix.shell().error("#{length(errors)} file(s) could not be formatted:")
 
         Enum.each(errors, fn {file, format_errors} ->
-          Mix.shell().error(
-            "  #{file}: #{format_errors |> List.wrap() |> Enum.map_join(", ", &Volt.JS.Check.lint_error_message/1)}"
-          )
+          Mix.shell().error("  #{file}: #{Enum.map_join(format_errors, ", ", & &1.message)}")
         end)
 
         false
@@ -94,12 +92,13 @@ defmodule Mix.Tasks.Volt.Js.Check do
   end
 
   defp print_lint_diags(diags) do
-    errors = Enum.count(diags, &(&1.severity == :deny))
-    warnings = Enum.count(diags, &(&1.severity == :warn))
+    errors = Enum.count(diags, &(&1.severity == :error))
+    warnings = Enum.count(diags, &(&1.severity == :warning))
 
     Enum.each(diags, fn diag ->
-      tag = if diag.severity == :deny, do: "error", else: "warn"
-      Mix.shell().error("  [#{tag}] #{diag.file}: #{diag.message} (#{diag.rule})")
+      location = if location = Volt.JS.Check.location(diag), do: "#{location}: ", else: ""
+      rule = if rule = diag[:rule], do: " (#{rule})", else: ""
+      Mix.shell().error("  [#{diag.severity}] #{location}#{diag.message}#{rule}")
     end)
 
     Mix.shell().error("#{errors} error(s), #{warnings} warning(s)")
diff --git a/lib/mix/tasks/volt.js.format.ex b/lib/mix/tasks/volt/js/format.ex
similarity index 70%
rename from lib/mix/tasks/volt.js.format.ex
rename to lib/mix/tasks/volt/js/format.ex
index e1f2e27..d08e711 100644
--- a/lib/mix/tasks/volt.js.format.ex
+++ b/lib/mix/tasks/volt/js/format.ex
@@ -8,8 +8,9 @@ defmodule Mix.Tasks.Volt.Js.Format do
 
       mix volt.js.format
 
-  Reads options from `config :volt, :format`. Falls back to `.oxfmtrc.json`.
-  File discovery uses `config :volt, sources:` and `ignore:`.
+  Reads options from the `:volt` key of `.formatter.exs`. Falls back to `.oxfmtrc.json`.
+  File discovery uses `config :volt, sources:` and `ignore:`, which `:root`,
+  `:sources`, and `:ignore` under the same `:volt` key override.
   No Node.js required.
   """
 
@@ -17,7 +18,7 @@ defmodule Mix.Tasks.Volt.Js.Format do
   def run(_args) do
     Mix.Task.run("app.config")
 
-    files = Volt.JS.Helpers.discover_format_files()
+    files = Volt.JS.Discovery.format_files()
 
     if files == [] do
       Mix.shell().info("No formattable files found")
diff --git a/lib/mix/tasks/volt.lint.ex b/lib/mix/tasks/volt/lint.ex
similarity index 70%
rename from lib/mix/tasks/volt.lint.ex
rename to lib/mix/tasks/volt/lint.ex
index 2b5372e..91216ae 100644
--- a/lib/mix/tasks/volt.lint.ex
+++ b/lib/mix/tasks/volt/lint.ex
@@ -11,10 +11,8 @@ defmodule Mix.Tasks.Volt.Lint do
 
   ## Options
 
-    * `--plugin` — enable an oxlint plugin (repeatable).
-      Available: `react`, `typescript`, `unicorn`, `import`, `jsdoc`,
-      `jest`, `vitest`, `jsx_a11y`, `nextjs`, `react_perf`, `promise`,
-      `node`, `vue`, `oxc`
+    * `--plugin` — enable an oxlint plugin (repeatable), such as `react`,
+      `unicorn`, or `jsx-a11y`. Accepts the plugin names of an oxlint config file.
 
     * `--fix` — show fix suggestions in output
 
@@ -23,7 +21,7 @@ defmodule Mix.Tasks.Volt.Lint do
   Configure lint settings in `config :volt, :lint`:
 
       config :volt, :lint,
-        plugins: [:typescript, :react],
+        plugins: ["typescript", "react"],
         rules: %{
           "no-console" => :warn,
           "eqeqeq" => :deny,
@@ -31,7 +29,17 @@ defmodule Mix.Tasks.Volt.Lint do
         },
         custom_rules: [
           {MyApp.NoConsoleLog, :warn}
+        ],
+        overrides: [
+          %{
+            files: ["colocated/**/*.js"],
+            rules: %{"unicorn/filename-case" => :allow}
+          }
         ]
+
+  Overrides are relative to the lint root and apply in order. They merge
+  individual `:rules`, `:env`, and `:globals` entries; later matches win.
+  Both lint commands share these settings. Plugins remain run-wide.
   """
   use Mix.Task
 
@@ -71,50 +79,33 @@ defmodule Mix.Tasks.Volt.Lint do
 
     plugins =
       case Keyword.get_values(parsed, :plugin) do
-        [] -> Keyword.get(config, :plugins, [:typescript])
-        cli_plugins -> Enum.map(cli_plugins, &String.to_atom/1)
+        [] -> Keyword.get(config, :plugins, ["typescript"])
+        cli_plugins -> cli_plugins
       end
 
-    rules = Keyword.get(config, :rules, %{})
-    custom_rules = Keyword.get(config, :custom_rules, [])
+    lint_config = Volt.JS.Lint.Config.new(config, Volt.Config.build().root)
     fix = Keyword.get(parsed, :fix, false)
 
-    files = Volt.JS.Helpers.discover_files(only: ~w(.js .ts .jsx .tsx))
+    files = Volt.JS.Discovery.files(tool: :lint, only: ~w".js .ts .jsx .tsx")
 
     if files == [] do
       Mix.shell().info("No lintable files found")
       :ok
     else
-      results = lint_files(files, plugins, rules, custom_rules, fix)
+      results = lint_files(files, lint_config, plugins, fix)
       print_results(results, files)
     end
   end
 
-  defp lint_files(files, plugins, rules, custom_rules, fix) do
+  defp lint_files(files, config, plugins, fix) do
     Enum.flat_map(files, fn file ->
       source = File.read!(file)
+      options = Volt.JS.Lint.Config.options(config, file)
+      options = Keyword.merge(options, plugins: plugins, fix: fix)
 
-      case OXC.Lint.run(source, file,
-             plugins: plugins,
-             rules: rules,
-             custom_rules: custom_rules,
-             fix: fix
-           ) do
-        {:ok, diags} ->
-          Enum.map(diags, &Map.put(&1, :file, file))
-
-        {:error, parse_errors} ->
-          Enum.map(parse_errors, fn msg ->
-            %{
-              file: file,
-              rule: "parse-error",
-              message: msg,
-              severity: :deny,
-              span: {0, 0},
-              labels: [],
-              help: nil
-            }
-          end)
+      case OXC.Lint.run(source, file, options) do
+        {:ok, diags} -> diags
+        {:error, parse_errors} -> parse_errors
       end
     end)
   end
@@ -165,8 +156,6 @@ defmodule Mix.Tasks.Volt.Lint do
   defp print_diagnostic(diag, edge_color) do
     tag = severity_tag(diag.severity)
     arrow = priority_arrow(diag.severity)
-    source = File.read!(diag.file)
-    {line, col} = offset_to_line_col(source, elem(diag.span, 0))
 
     Mix.shell().info(
       IO.ANSI.format([
@@ -190,20 +179,17 @@ defmodule Mix.Tasks.Volt.Lint do
         "┃       ",
         :reset,
         :faint,
-        diag.file,
+        Volt.JS.Check.location(diag) || "",
         :default_color,
         :faint,
-        ":#{line}:#{col}",
-        " #(",
-        diag.rule,
-        ")"
+        if(rule = diag[:rule], do: " #(#{rule})", else: "")
       ])
     )
   end
 
   defp print_summary(results, files) do
-    errors = Enum.count(results, &(&1.severity == :deny))
-    warnings = Enum.count(results, &(&1.severity == :warn))
+    errors = Enum.count(results, &(&1.severity == :error))
+    warnings = Enum.count(results, &(&1.severity == :warning))
 
     by_category =
       results
@@ -254,25 +240,15 @@ defmodule Mix.Tasks.Volt.Lint do
     end)
   end
 
-  defp severity_tag(:deny), do: "[E]"
-  defp severity_tag(:warn), do: "[W]"
-  defp severity_tag(_), do: "[I]"
+  defp severity_tag(:error), do: "[E]"
+  defp severity_tag(:warning), do: "[W]"
 
-  defp priority_arrow(:deny), do: "↗"
-  defp priority_arrow(:warn), do: "→"
-  defp priority_arrow(_), do: "→"
+  defp priority_arrow(:error), do: "↗"
+  defp priority_arrow(:warning), do: "→"
 
   defp pl(1), do: ""
   defp pl(_), do: "s"
 
-  defp offset_to_line_col(source, offset) do
-    prefix = binary_part(source, 0, min(offset, byte_size(source)))
-    lines = String.split(prefix, "\n")
-    line = length(lines)
-    col = lines |> List.last() |> String.length() |> Kernel.+(1)
-    {line, col}
-  end
-
   defp term_columns do
     case :io.columns() do
       {:ok, cols} -> cols
diff --git a/lib/mix/tasks/volt/priv/vendor.ex b/lib/mix/tasks/volt/priv/vendor.ex
new file mode 100644
index 0000000..291e4ea
--- /dev/null
+++ b/lib/mix/tasks/volt/priv/vendor.ex
@@ -0,0 +1,34 @@
+defmodule Mix.Tasks.Volt.Priv.Vendor do
+  use Mix.Task
+
+  @shortdoc "Vendor npm packages for browser code under priv"
+
+  @moduledoc """
+  Vendors the npm packages that `DIR/package.json` lists into `DIR/node_modules`,
+  keeping only the files the sources in `DIR` reach. See `Volt.Priv.Vendor`.
+
+      mix volt.priv.vendor priv/ts
+      mix volt.priv.vendor priv/ts --update
+
+  Run it before `mix hex.publish`, so the package ships the vendored files.
+
+  ## Options
+
+    * `--update` — resolve the versions again instead of using `DIR/npm.lock`
+  """
+
+  @impl true
+  def run(args) do
+    {opts, dirs} = OptionParser.parse!(args, strict: [update: :boolean])
+
+    if dirs == [], do: Mix.raise("Expected a directory, such as: mix volt.priv.vendor priv/ts")
+
+    Mix.Task.run("app.config")
+    Application.ensure_all_started(:req)
+
+    for dir <- dirs do
+      files = Volt.Priv.Vendor.run!(dir, update: opts[:update] == true)
+      Mix.shell().info("Vendored #{length(files)} files into #{Path.join(dir, "node_modules")}")
+    end
+  end
+end
diff --git a/lib/volt.ex b/lib/volt.ex
index 875f202..7b31950 100644
--- a/lib/volt.ex
+++ b/lib/volt.ex
@@ -21,6 +21,10 @@ defmodule Volt do
 
   alias Volt.URL
 
+  @doc "Build the complete configured frontend output."
+  @spec build(keyword()) :: {:ok, Volt.Build.Result.t()} | {:error, term()}
+  def build(opts \\ []), do: Volt.Build.run(opts)
+
   @doc """
   Returns the browser path for a Volt-managed static asset.
 
diff --git a/lib/volt/application.ex b/lib/volt/application.ex
index 5d54fce..f2ac574 100644
--- a/lib/volt/application.ex
+++ b/lib/volt/application.ex
@@ -4,17 +4,26 @@ defmodule Volt.Application do
 
   @impl true
   def start(_type, _args) do
+    Volt.Paths.capture_root()
     Volt.Cache.create_table()
+    Volt.Dev.Assets.create_table()
     Volt.HMR.ImportGraph.create_table()
     Volt.HMR.GlobGraph.create_table()
     Volt.HMR.StyleGraph.create_table()
     Volt.HMR.ModuleGraph.create_table()
+    Volt.HMR.Errors.create_table()
+    Volt.HMR.Documents.create_table()
+    Volt.Dev.Prebundled.create_table()
 
+    # Watchers release their Tailwind contexts when they terminate, so the
+    # Tailwind processes start before them and stop after them.
     children = [
       {Registry, keys: :duplicate, name: Volt.HMR.Registry},
+      {Registry, keys: :unique, name: Volt.Tailwind.Registry},
+      {DynamicSupervisor, strategy: :one_for_one, name: Volt.Tailwind.WorkerSupervisor},
+      Volt.Tailwind.Runtime,
       {Registry, keys: :unique, name: Volt.Dev.WatcherRegistry},
-      {DynamicSupervisor, strategy: :one_for_one, name: Volt.Dev.WatcherSupervisor},
-      {Volt.Tailwind, Volt.Config.tailwind()}
+      {DynamicSupervisor, strategy: :one_for_one, name: Volt.Dev.WatcherSupervisor}
     ]
 
     opts = [strategy: :one_for_one, name: Volt.Supervisor]
diff --git a/lib/volt/assets.ex b/lib/volt/assets.ex
index 074fba6..153f993 100644
--- a/lib/volt/assets.ex
+++ b/lib/volt/assets.ex
@@ -95,8 +95,31 @@ defmodule Volt.Assets do
 
   @doc "Generate a JS module for an asset and return emitted asset metadata."
   @spec emit_js_module(String.t(), keyword()) ::
-          {:ok, %{code: String.t(), assets: [String.t() | map()]}} | {:error, term()}
+          {:ok, %{code: String.t(), assets: [Volt.Builder.Asset.t()]}} | {:error, term()}
   def emit_js_module(path, opts \\ []) do
+    with {:ok, prepared} <- prepare_js_module(path, opts) do
+      case Keyword.get(opts, :outdir) do
+        nil ->
+          :ok
+
+        outdir ->
+          write_artifacts(prepared.artifacts, outdir)
+      end
+
+      {:ok, %{code: prepared.code, assets: prepared.assets}}
+    end
+  end
+
+  @doc "Write prepared binary assets for the immediate-emission APIs."
+  def write_artifacts(artifacts, outdir) do
+    Enum.each(artifacts, fn %Volt.Builder.Artifact{file: file, content: content} ->
+      File.mkdir_p!(outdir)
+      File.write!(Path.join(outdir, file), content)
+    end)
+  end
+
+  @doc "Prepare an asset module and its output artifacts without writing files."
+  def prepare_js_module(path, opts \\ []) do
     cond do
       Keyword.get(opts, :raw, false) ->
         raw_asset(path)
@@ -133,23 +156,22 @@ defmodule Volt.Assets do
   """
   @spec copy_hashed(String.t(), String.t()) :: {:ok, String.t()}
   def copy_hashed(source_path, outdir) do
-    content = File.read!(source_path)
-    ext = Path.extname(source_path)
-    name = Path.basename(source_path, ext)
-    hash = Volt.Format.content_hash(content)
-    filename = "#{name}-#{hash}#{ext}"
-    dest = Path.join(outdir, filename)
-
+    artifact = prepare_hashed(source_path)
     File.mkdir_p!(outdir)
-    File.write!(dest, content)
+    File.write!(Path.join(outdir, artifact.file), artifact.content)
+    {:ok, artifact.file}
+  end
 
-    {:ok, filename}
+  @doc false
+  @spec prepare_hashed(String.t()) :: Volt.Builder.Artifact.t()
+  def prepare_hashed(source_path) do
+    Volt.Builder.Artifact.asset(source_path, File.read!(source_path))
   end
 
   @doc "Build manifest metadata for an emitted asset."
-  @spec manifest_asset(String.t(), String.t(), keyword()) :: map()
+  @spec manifest_asset(String.t(), String.t(), keyword()) :: Volt.Builder.Asset.t()
   def manifest_asset(source_path, filename, opts \\ []) do
-    %{
+    %Volt.Builder.Asset{
       src: source_path |> asset_src(Keyword.get(opts, :root)) |> String.trim_leading("/"),
       file: filename
     }
@@ -254,10 +276,10 @@ defmodule Volt.Assets do
         url = Keyword.get(opts, :url_path) || Volt.URL.join(prefix, Path.basename(path))
         {:ok, asset_module(url)}
 
-      outdir ->
-        {:ok, filename} = copy_hashed(path, outdir)
-        asset = manifest_asset(path, filename, root: Keyword.get(opts, :root))
-        {:ok, asset_module(Volt.URL.join(prefix, filename), [asset])}
+      _outdir ->
+        artifact = prepare_hashed(path)
+        asset = manifest_asset(path, artifact.file, root: Keyword.get(opts, :root))
+        {:ok, asset_module(Volt.URL.join(prefix, artifact.file), [asset], [artifact])}
     end
   end
 
@@ -274,8 +296,8 @@ defmodule Volt.Assets do
     end
   end
 
-  defp asset_module(value, assets \\ []) do
-    %{code: export_default_literal(value), assets: assets}
+  defp asset_module(value, assets \\ [], artifacts \\ []) do
+    %{code: export_default_literal(value), assets: assets, artifacts: artifacts}
   end
 
   defp export_default_literal(value) do
diff --git a/lib/volt/build.ex b/lib/volt/build.ex
new file mode 100644
index 0000000..48ec566
--- /dev/null
+++ b/lib/volt/build.ex
@@ -0,0 +1,135 @@
+defmodule Volt.Build do
+  @moduledoc """
+  Builds the complete configured frontend output.
+
+  This orchestrator composes Tailwind roots with the ordinary Volt module graph,
+  merges their typed build results, and publishes one final manifest.
+  """
+
+  @spec run(keyword()) :: {:ok, Volt.Build.Result.t()} | {:error, term()}
+  def run(opts \\ []) do
+    {profile, opts} = Keyword.pop(opts, :profile)
+    config = Volt.Config.build(profile, opts)
+    tailwind = Keyword.get(opts, :tailwind, Volt.Config.tailwind(profile))
+    entries = List.wrap(config.entry)
+    root_outdir = to_string(config.outdir)
+    layout = Volt.Build.Layout.new(config.output_layout, config.assets_dir)
+
+    with {:ok, tailwind_result, tailwind_plan} <-
+           build_tailwind(tailwind, config, opts, layout),
+         {:ok, asset_result, asset_plan} <- build_assets(entries, config, opts, layout) do
+      tailwind_result = prefix_manifest(tailwind_result, layout.styles)
+      asset_result = prefix_manifest(asset_result, layout.scripts)
+
+      artifacts =
+        prefix_artifacts(tailwind_plan, layout.styles) ++
+          prefix_artifacts(asset_plan, layout.scripts)
+
+      with {:ok, result} <- build_result(tailwind_result, asset_result),
+           {:ok, plan} <-
+             Volt.Builder.Plan.new(artifacts ++ manifest_artifacts(result.manifest, opts)),
+           :ok <- Volt.Builder.Plan.validate_manifest(plan, result.manifest),
+           {:ok, destination, plan} <-
+             Volt.PublicDir.prepare_output(
+               plan,
+               root_outdir,
+               Volt.PublicDir.resolve(config.public_dir),
+               root_outdir
+             ),
+           :ok <- Volt.Builder.Writer.write_plan(destination, plan) do
+        {:ok, result}
+      end
+    end
+  end
+
+  defp build_tailwind(false, _config, _opts, _layout), do: empty_plan()
+  defp build_tailwind(true, config, opts, layout), do: prepare_tailwind([], config, opts, layout)
+  defp build_tailwind([], _config, _opts, _layout), do: empty_plan()
+  defp build_tailwind(nil, _config, _opts, _layout), do: empty_plan()
+
+  defp build_tailwind(tailwind, config, opts, layout),
+    do: prepare_tailwind(tailwind, config, opts, layout)
+
+  defp prepare_tailwind(tailwind, config, opts, layout) do
+    overrides =
+      []
+      |> put_present(:css, opts[:tailwind_css])
+      |> put_present(:name, opts[:tailwind_name])
+      |> put_present(:sources, opts[:tailwind_sources])
+
+    root = Volt.Config.Tailwind.new(tailwind, overrides)
+
+    Volt.Tailwind.Build.prepare(root,
+      outdir: Path.join(to_string(config.outdir), layout.styles),
+      hash: config.hash,
+      minify: config.minify,
+      root: to_string(config.root),
+      asset_url_prefix: Volt.URL.join(config.asset_url_prefix, layout.styles)
+    )
+  end
+
+  defp build_assets([], _config, _opts, _layout), do: empty_plan()
+
+  defp build_assets(entries, config, opts, layout) do
+    builder_outdir = Path.join(to_string(config.outdir), layout.scripts)
+    asset_url_prefix = Volt.URL.join(config.asset_url_prefix, layout.scripts)
+
+    config
+    |> Map.from_struct()
+    |> Map.put(:entry, entries)
+    |> Map.put(:outdir, builder_outdir)
+    |> Map.put(:asset_url_prefix, asset_url_prefix)
+    |> Map.put(:write_manifest, false)
+    |> Map.merge(Map.new(Keyword.take(opts, [:name])))
+    |> Map.to_list()
+    |> Volt.Builder.prepare()
+  end
+
+  defp empty_plan, do: {:ok, %Volt.Builder.Result{}, %Volt.Builder.Plan{artifacts: []}}
+
+  defp prefix_artifacts(plan, ""), do: plan.artifacts
+
+  defp prefix_artifacts(plan, prefix) do
+    Enum.map(plan.artifacts, fn artifact ->
+      %{artifact | file: Path.join(prefix, artifact.file)}
+    end)
+  end
+
+  defp manifest_artifacts(manifest, opts) do
+    if Keyword.get(opts, :write_manifest, true),
+      do: [%Volt.Builder.Artifact{file: "manifest.json", content: Jason.encode!(manifest)}],
+      else: []
+  end
+
+  defp build_result(styles_result, assets_result) do
+    collisions =
+      Volt.Builder.ManifestEntry.conflicts(styles_result.manifest, assets_result.manifest)
+
+    case Enum.sort(collisions) do
+      [] ->
+        {:ok,
+         %Volt.Build.Result{
+           assets: assets_result,
+           styles: styles_result.styles ++ assets_result.styles,
+           manifest: Map.merge(styles_result.manifest, assets_result.manifest)
+         }}
+
+      keys ->
+        {:error, {:manifest_collision, keys}}
+    end
+  end
+
+  defp prefix_manifest(result, ""), do: result
+
+  defp prefix_manifest(result, prefix) do
+    manifest =
+      Map.new(result.manifest, fn {key, %Volt.Builder.ManifestEntry{} = entry} ->
+        {key, Volt.Builder.ManifestEntry.prefix_paths(entry, prefix)}
+      end)
+
+    %{result | manifest: manifest}
+  end
+
+  defp put_present(opts, _key, nil), do: opts
+  defp put_present(opts, key, value), do: Keyword.put(opts, key, value)
+end
diff --git a/lib/volt/build/layout.ex b/lib/volt/build/layout.ex
new file mode 100644
index 0000000..bac5958
--- /dev/null
+++ b/lib/volt/build/layout.ex
@@ -0,0 +1,36 @@
+defmodule Volt.Build.Layout do
+  @moduledoc "Output locations for a complete frontend build."
+
+  @enforce_keys [:scripts, :styles]
+  defstruct [:scripts, :styles]
+
+  @type t :: %__MODULE__{scripts: String.t(), styles: String.t()}
+
+  @spec new(:split | :flat, String.t()) :: t()
+  def new(layout, assets_dir \\ "") do
+    if assets_dir != "" and
+         (Path.type(assets_dir) != :relative or
+            Enum.any?(Path.split(assets_dir), &(&1 in [".", ".."])) or
+            String.contains?(assets_dir, ["\\", ":", <<0>>])) do
+      raise ArgumentError, "assets_dir must be a relative directory within outdir"
+    end
+
+    layout = preset(layout)
+
+    %__MODULE__{
+      scripts: join(assets_dir, layout.scripts),
+      styles: join(assets_dir, layout.styles)
+    }
+  end
+
+  defp join("", suffix), do: suffix
+  defp join(prefix, ""), do: prefix
+  defp join(prefix, suffix), do: Path.join(prefix, suffix)
+
+  defp preset(:split), do: %__MODULE__{scripts: "js", styles: "css"}
+  defp preset(:flat), do: %__MODULE__{scripts: "", styles: ""}
+
+  defp preset(other) do
+    raise ArgumentError, "expected output_layout to be :split or :flat, got: #{inspect(other)}"
+  end
+end
diff --git a/lib/volt/build/result.ex b/lib/volt/build/result.ex
new file mode 100644
index 0000000..e778331
--- /dev/null
+++ b/lib/volt/build/result.ex
@@ -0,0 +1,12 @@
+defmodule Volt.Build.Result do
+  @moduledoc "Complete frontend build result with script and stylesheet outputs."
+
+  @enforce_keys [:assets, :styles, :manifest]
+  defstruct assets: nil, styles: [], manifest: %{}
+
+  @type t :: %__MODULE__{
+          assets: Volt.Builder.Result.t(),
+          styles: [Volt.Builder.OutputFile.t()],
+          manifest: %{String.t() => Volt.Builder.ManifestEntry.t()}
+        }
+end
diff --git a/lib/volt/builder.ex b/lib/volt/builder.ex
index b1e8354..3eea110 100644
--- a/lib/volt/builder.ex
+++ b/lib/volt/builder.ex
@@ -11,21 +11,13 @@ defmodule Volt.Builder do
   manifest.
   """
 
-  alias Volt.Builder.{Bundle, Collector, Output}
+  alias Volt.Builder.{Bundle, Collector, Naming, Output}
   alias Volt.Paths
 
   @css_exts Volt.JS.Extensions.css()
   @css_import_noop "data:text/javascript,export{}"
   @dynamic_css_import_noop "Promise.resolve({ default: undefined })"
 
-  @type build_result :: %{
-          js:
-            %{path: String.t(), size: non_neg_integer()}
-            | [%{path: String.t(), size: non_neg_integer()}],
-          css: %{path: String.t(), size: non_neg_integer()} | nil,
-          manifest: %{String.t() => String.t()}
-        }
-
   @doc """
   Build production assets from one or more entry files.
 
@@ -40,6 +32,8 @@ defmodule Volt.Builder do
     * `:define` — compile-time replacements
     * `:node_modules` — path to node_modules (default: auto-detect)
     * `:resolve_dirs` — additional directories to resolve bare specifiers (e.g. `["deps"]`)
+    * `:package_scopes` — source-root/package-directory pairs. Bare imports originating
+      below a source root resolve from its package directory before global package roots.
     * `:name` — output base name (default: derived from entry filename)
     * `:aliases` — import alias map (e.g. `%{"@" => "assets/src"}`)
     * `:plugins` — list of `Volt.Plugin` modules. Plugin `resolve/2` and `load/1` hooks can provide virtual modules and virtual build entries.
@@ -48,29 +42,49 @@ defmodule Volt.Builder do
     * `:asset_url_prefix` — public URL prefix for emitted asset references (default: `"/assets"`)
     * `:code_splitting` — split dynamic imports and multi-entry ESM shared modules into chunks (default: `true`)
     * `:tree_shaking` — remove unused exports (default: `true`)
+    * `:declarations` — write one `.d.ts` per script entry beside its bundle, with the types the entry exports (default: `false`). See `Volt.Builder.Declarations`.
     * `:chunks` — manual chunk definitions, map of chunk name to list of patterns:
 
           chunks: %{"vendor" => ["vue", "vue-router"], "ui" => ["assets/src/components"]}
-    * `:external` — specifiers to exclude from the bundle and access as globals.
-      Accepts a list (global name auto-derived) or a map of `specifier => global_name`:
+    * `:write_manifest` — write `manifest.json` after building (default: `true`)
+    * `:external` — specifiers to exclude from the bundle. With `format: :iife`
+      they are read from global variables; with `:esm` and `:cjs` the imports
+      stay in the output. Accepts a list (global name auto-derived) or a map of
+      `specifier => global_name`, whose names apply to `:iife` only:
 
           external: ["vue", "phoenix"]
           external: %{"vue" => "Vue", "phoenix" => "Phoenix"}
   """
-  @spec build(keyword()) :: {:ok, build_result()} | {:error, term()}
+  @spec build(keyword()) :: {:ok, Volt.Builder.Result.t()} | {:error, term()}
   def build(opts) do
+    outdir = opts |> Keyword.get(:outdir, Paths.static()) |> Path.expand()
+
+    public_dir = opts |> Keyword.get(:public_dir, false) |> Volt.PublicDir.resolve()
+
+    with {:ok, result, plan} <- prepare(opts),
+         {:ok, static_root, plan} <-
+           Volt.PublicDir.prepare_output(
+             plan,
+             outdir,
+             public_dir,
+             Path.dirname(outdir)
+           ),
+         :ok <- Volt.Builder.Writer.write_plan(static_root, plan) do
+      {:ok, result}
+    end
+  end
+
+  @doc "Prepare graph output and its manifest without writing destination files."
+  def prepare(opts) do
     plugins = Keyword.get(opts, :plugins, [])
 
     entries =
       opts |> Keyword.fetch!(:entry) |> List.wrap() |> Enum.map(&resolve_entry(&1, plugins))
 
-    public_dir = opts |> Keyword.get(:public_dir, false) |> Volt.PublicDir.resolve()
     name = Keyword.get(opts, :name)
     {ctx, build_ctx} = build_contexts(entries, opts)
 
-    Volt.PublicDir.copy(public_dir, Path.dirname(build_ctx.outdir))
-
-    expanded_entries = Enum.flat_map(entries, &expand_entry(&1, name))
+    expanded_entries = entries |> Enum.flat_map(&expand_entry(&1, name)) |> unique_entry_names()
 
     results =
       if shared_entries?(expanded_entries, build_ctx, name) do
@@ -79,9 +93,17 @@ defmodule Volt.Builder do
         build_isolated_entries(expanded_entries, ctx, build_ctx)
       end
 
-    with {:ok, result} <- finalize_build_results(results) do
-      Volt.Builder.Writer.write_manifest(build_ctx.outdir, result.manifest)
-      {:ok, result}
+    with {:ok, result, plan} <- finalize_build_results(results),
+         :ok <- Volt.Builder.Plan.validate_manifest(plan, result.manifest) do
+      artifacts =
+        if Keyword.get(opts, :write_manifest, true),
+          do: [
+            %Volt.Builder.Artifact{file: "manifest.json", content: Jason.encode!(result.manifest)}
+            | plan.artifacts
+          ],
+          else: plan.artifacts
+
+      with {:ok, plan} <- Volt.Builder.Plan.new(artifacts), do: {:ok, result, plan}
     end
   end
 
@@ -95,17 +117,17 @@ defmodule Volt.Builder do
   defp build_shared_entries(entries, ctx, build_ctx) do
     with {:ok, collected} <- collect_shared_entries(entries, ctx),
          false <- label_collision?(collected.path_labels),
-         {:ok, worker_results} <- build_worker_results(collected.workers, ctx, build_ctx),
+         {:ok, worker_results, worker_artifacts, worker_metadata} <-
+           build_worker_results(collected.workers, ctx, build_ctx),
          {:ok, compiled} <- compile_all(collected.modules, build_ctx.target, ctx) do
       compiled =
         rewrite_nonlocal_labels(compiled, collected.specifier_labels, collected.path_labels)
 
       output_ctx = %Volt.Builder.OutputContext{
-        plugins: ctx.plugins,
-        external_set: ctx.external,
-        external_globals: ctx.external_globals,
-        workers: collected.workers,
-        worker_results: worker_results
+        output_externals(ctx, build_ctx)
+        | plugins: ctx.plugins,
+          workers: collected.workers,
+          worker_results: worker_results
       }
 
       out = %Volt.Builder.BuildContext{
@@ -118,7 +140,9 @@ defmodule Volt.Builder do
         asset_url_prefix: build_ctx.asset_url_prefix
       }
 
-      case Output.build_shared_entries(
+      compiled = %{compiled | artifacts: compiled.artifacts ++ worker_artifacts}
+
+      case Output.prepare_shared_entries(
              entries,
              compiled,
              collected.modules,
@@ -130,6 +154,12 @@ defmodule Volt.Builder do
 
         result ->
           result
+          |> merge_worker_metadata(worker_metadata)
+          |> with_declarations(
+            Enum.map(entries, fn {entry, :script, name} -> {entry, name} end),
+            ctx,
+            build_ctx
+          )
       end
     else
       true -> build_isolated_entries(entries, ctx, build_ctx) |> finalize_build_results()
@@ -224,11 +254,10 @@ defmodule Volt.Builder do
       compiled = rewrite_nonlocal_labels(compiled, specifier_labels, path_labels)
 
       output_ctx = %Volt.Builder.OutputContext{
-        plugins: ctx.plugins,
-        external_set: ctx.external,
-        external_globals: ctx.external_globals,
-        workers: workers,
-        worker_results: %{}
+        output_externals(ctx, build_ctx)
+        | plugins: ctx.plugins,
+          workers: workers,
+          worker_results: %{}
       }
 
       out = %Volt.Builder.BuildContext{
@@ -281,15 +310,16 @@ defmodule Volt.Builder do
     with {:ok, modules, dep_map, workers, specifier_labels, path_labels} <-
            Collector.collect(entry, ctx),
          {:ok, compiled} <- compile_all(modules, target, ctx),
-         {:ok, worker_results} <- build_worker_results(workers, ctx, build_ctx) do
+         {:ok, worker_results, worker_artifacts, worker_metadata} <-
+           build_worker_results(workers, ctx, build_ctx) do
       compiled = rewrite_nonlocal_labels(compiled, specifier_labels, path_labels)
+      compiled = %{compiled | artifacts: compiled.artifacts ++ worker_artifacts}
 
       output_ctx = %Volt.Builder.OutputContext{
-        plugins: ctx.plugins,
-        external_set: ctx.external,
-        external_globals: ctx.external_globals,
-        workers: workers,
-        worker_results: worker_results
+        output_externals(ctx, build_ctx)
+        | plugins: ctx.plugins,
+          workers: workers,
+          worker_results: worker_results
       }
 
       out = %Volt.Builder.BuildContext{
@@ -306,11 +336,16 @@ defmodule Volt.Builder do
         code_splitting and
           (has_dynamic_imports?(dep_map) or build_ctx.chunks != %{})
 
-      if use_chunks do
-        Output.build_chunks(entry, name, compiled, {modules, dep_map}, out)
-      else
-        Output.build_single(entry, name, compiled, out)
-      end
+      prepared =
+        if use_chunks do
+          Output.prepare_chunks(entry, name, compiled, {modules, dep_map}, out)
+        else
+          Output.prepare_single(entry, name, compiled, out)
+        end
+
+      prepared
+      |> merge_worker_metadata(worker_metadata)
+      |> with_declarations([{entry, name}], ctx, build_ctx)
     end
   end
 
@@ -322,9 +357,11 @@ defmodule Volt.Builder do
          {:ok, compiled} <-
            Volt.Pipeline.compile(entry, source,
              minify: bundle_opts[:minify] || false,
+             node_modules: bundle_opts[:node_modules],
+             resolve_dirs: bundle_opts[:resolve_dirs] || [],
              mode: :production
            ) do
-      Volt.Builder.Writer.build_style_entry(
+      Volt.Builder.Writer.prepare_style_entry(
         name,
         compiled.code,
         outdir,
@@ -370,6 +407,7 @@ defmodule Volt.Builder do
     asset_url_prefix = Keyword.get(opts, :asset_url_prefix, Paths.prefix())
     aliases = Keyword.get(opts, :aliases, %{})
     code_splitting = Keyword.get(opts, :code_splitting, true)
+    declarations = Keyword.get(opts, :declarations, false)
     tree_shaking = Keyword.get(opts, :tree_shaking, true)
     chunks = Keyword.get(opts, :chunks, %{})
     format = Keyword.get(opts, :format, :iife)
@@ -382,6 +420,7 @@ defmodule Volt.Builder do
         NPM.Resolution.PackageResolver.find_node_modules(entry_base(first_entry))
 
     resolve_dirs = Keyword.get(opts, :resolve_dirs, []) |> Enum.map(&Path.expand/1)
+    package_scopes = opts |> Keyword.get(:package_scopes, []) |> normalize_package_scopes()
     loaders = Keyword.get(opts, :loaders, %{})
     module_types = Keyword.get(opts, :module_types, %{})
     import_source = opts |> Keyword.get(:import_source) |> to_string_or_nil()
@@ -399,6 +438,7 @@ defmodule Volt.Builder do
     ctx = %Volt.Builder.Context{
       node_modules: node_modules,
       resolve_dirs: resolve_dirs,
+      package_scopes: package_scopes,
       aliases: aliases,
       plugins: Keyword.get(opts, :plugins, []),
       external: external_set,
@@ -433,6 +473,7 @@ defmodule Volt.Builder do
       bundle_opts: bundle_opts,
       asset_url_prefix: asset_url_prefix,
       code_splitting: code_splitting,
+      declarations: declarations,
       sourcemap_hidden: sourcemap_opt == :hidden,
       chunks: chunks
     }
@@ -452,9 +493,10 @@ defmodule Volt.Builder do
 
     duplicate_worker_basenames = duplicate_worker_basenames(worker_specs)
 
-    Enum.reduce_while(worker_specs, {:ok, %{}}, fn {_specifier, resolved_path}, {:ok, acc} ->
+    Enum.reduce_while(worker_specs, {:ok, %{}, [], []}, fn {_specifier, resolved_path},
+                                                           {:ok, acc, artifacts, metadata} ->
       if Map.has_key?(acc, resolved_path) do
-        {:cont, {:ok, acc}}
+        {:cont, {:ok, acc, artifacts, metadata}}
       else
         worker_name = worker_output_name(resolved_path, duplicate_worker_basenames)
 
@@ -465,14 +507,89 @@ defmodule Volt.Builder do
                ctx,
                %{build_ctx | code_splitting: false}
              ) do
-          {:ok, %{js: %{path: path}}} ->
-            {:cont, {:ok, Map.put(acc, resolved_path, Path.basename(path))}}
+          {:ok, %{js: %{path: path}} = result, plan} ->
+            {:cont,
+             {:ok, Map.put(acc, resolved_path, Path.basename(path)), [plan.artifacts | artifacts],
+              [result | metadata]}}
 
           {:error, reason} ->
             {:halt, {:error, {:worker_build_failed, resolved_path, reason}}}
         end
       end
     end)
+    |> case do
+      {:ok, urls, artifacts, metadata} ->
+        {:ok, urls, List.flatten(artifacts), Enum.reverse(metadata)}
+
+      {:error, _} = error ->
+        error
+    end
+  end
+
+  # A library's types go beside its bundle, under the entry's name and no hash:
+  # `package.json` names the file.
+  defp with_declarations({:ok, result, plan}, entries, ctx, %{declarations: true} = build_ctx) do
+    Enum.reduce_while(entries, {:ok, [], []}, fn {entry, name}, {:ok, outputs, artifacts} ->
+      case Volt.Builder.Declarations.bundle(entry, ctx) do
+        {:ok, dts} ->
+          file = "#{name}.d.ts"
+          artifact = %Volt.Builder.Artifact{file: file, content: dts}
+
+          output = %Volt.Builder.OutputFile{
+            path: Path.join(build_ctx.outdir, file),
+            size: byte_size(dts)
+          }
+
+          {:cont, {:ok, [output | outputs], [artifact | artifacts]}}
+
+        error ->
+          {:halt, error}
+      end
+    end)
+    |> case do
+      {:ok, outputs, artifacts} ->
+        with {:ok, plan} <- Volt.Builder.Plan.new(plan.artifacts ++ Enum.reverse(artifacts)) do
+          {:ok, %{result | declarations: result.declarations ++ Enum.reverse(outputs)}, plan}
+        end
+
+      error ->
+        error
+    end
+  end
+
+  defp with_declarations(prepared, _entries, _ctx, _build_ctx), do: prepared
+
+  defp merge_worker_metadata({:error, _} = error, _workers), do: error
+
+  defp merge_worker_metadata({:ok, result, plan}, workers) do
+    Enum.reduce_while(workers, {:ok, result, plan}, fn worker, {:ok, acc, plan} ->
+      case Volt.Builder.ManifestEntry.conflicts(worker.manifest, acc.manifest) do
+        [] ->
+          merged = %{
+            acc
+            | manifest: Map.merge(acc.manifest, worker.manifest),
+              styles: [worker.styles | acc.styles],
+              chunks: [worker.js, worker.chunks | acc.chunks]
+          }
+
+          {:cont, {:ok, merged, plan}}
+
+        keys ->
+          {:halt, {:error, {:manifest_collision, Enum.sort(keys)}}}
+      end
+    end)
+    |> case do
+      {:ok, merged, plan} ->
+        {:ok,
+         %{
+           merged
+           | styles: merged.styles |> List.flatten() |> Enum.uniq(),
+             chunks: merged.chunks |> List.flatten() |> Enum.uniq()
+         }, plan}
+
+      {:error, _} = error ->
+        error
+    end
   end
 
   defp duplicate_worker_basenames(worker_specs) do
@@ -489,7 +606,7 @@ defmodule Volt.Builder do
     name = resolved_path |> Path.basename() |> Path.rootname()
 
     if MapSet.member?(duplicate_basenames, name) do
-      "#{name}-#{Volt.Format.content_hash(resolved_path)}"
+      "#{name}-#{Volt.Builder.Naming.hash(resolved_path)}"
     else
       name
     end
@@ -506,8 +623,11 @@ defmodule Volt.Builder do
   defp compile_modules(modules, ctx) do
     Enum.reduce_while(modules, {:ok, []}, fn {path, label, source}, {:ok, acc} ->
       case compile_module(path, label, source, ctx) do
-        {:ok, js, css, assets} -> {:cont, {:ok, [{label, js, css_part(path, css), assets} | acc]}}
-        {:error, _} = error -> {:halt, error}
+        {:ok, js, css, assets, artifacts} ->
+          {:cont, {:ok, [{label, js, css_part(path, css), assets, artifacts} | acc]}}
+
+        {:error, _} = error ->
+          {:halt, error}
       end
     end)
   end
@@ -526,16 +646,27 @@ defmodule Volt.Builder do
   end
 
   defp merge_compiled(compiled) do
-    {js_files, css_parts, assets} =
-      compiled
-      |> Enum.reverse()
-      |> Enum.reduce({[], [], []}, fn {label, js, css, assets}, {js_acc, css_acc, asset_acc} ->
-        {[{label, js} | js_acc], if(css, do: [css | css_acc], else: css_acc),
-         [assets | asset_acc]}
+    result =
+      Enum.reduce(Enum.reverse(compiled), %Volt.Builder.Compiled{}, fn {label, js, css, assets,
+                                                                        artifacts},
+                                                                       acc ->
+        %{
+          acc
+          | scripts: [{label, js} | acc.scripts],
+            styles: if(css, do: [css | acc.styles], else: acc.styles),
+            assets: [assets | acc.assets],
+            artifacts: [artifacts | acc.artifacts]
+        }
       end)
 
     {:ok,
-     {Enum.reverse(js_files), Enum.reverse(css_parts), assets |> List.flatten() |> Enum.uniq()}}
+     %{
+       result
+       | scripts: Enum.reverse(result.scripts),
+         styles: Enum.reverse(result.styles),
+         assets: result.assets |> List.flatten() |> Enum.uniq(),
+         artifacts: result.artifacts |> List.flatten() |> Enum.uniq()
+     }}
   end
 
   defp compile_module(module_id, _label, source, ctx) do
@@ -556,7 +687,7 @@ defmodule Volt.Builder do
 
       true ->
         case Volt.Builder.Compiler.compile(module_id, source, ctx) do
-          {:ok, %{code: code, css: css}} -> {:ok, code, css, []}
+          {:ok, %{code: code, css: css}} -> {:ok, code, css, [], []}
           {:error, _} = error -> error
         end
     end
@@ -582,9 +713,12 @@ defmodule Volt.Builder do
       root: ctx.asset_root
     ]
 
-    case Volt.Assets.emit_js_module(path, asset_opts) do
-      {:ok, %{code: js, assets: assets}} -> {:ok, js, nil, assets}
-      {:error, _} = error -> error
+    case Volt.Assets.prepare_js_module(path, asset_opts) do
+      {:ok, %{code: js, assets: assets, artifacts: artifacts}} ->
+        {:ok, js, nil, assets, artifacts}
+
+      {:error, _} = error ->
+        error
     end
   end
 
@@ -594,12 +728,16 @@ defmodule Volt.Builder do
 
   defp compile_css_import(path, source, ctx) do
     case Volt.Builder.Compiler.compile(path, source, ctx) do
-      {:ok, %{code: css}} -> {:ok, "export default undefined;", css, []}
+      {:ok, %{code: css}} -> {:ok, "export default undefined;", css, [], []}
       {:error, _} = error -> error
     end
   end
 
-  defp rewrite_nonlocal_labels({js_files, css_parts, assets}, specifier_labels, path_labels) do
+  defp rewrite_nonlocal_labels(
+         %Volt.Builder.Compiled{scripts: js_files} = compiled,
+         specifier_labels,
+         path_labels
+       ) do
     label_to_path = Map.new(path_labels, fn {path, label} -> {label, path} end)
 
     global_specifier_map =
@@ -631,7 +769,7 @@ defmodule Volt.Builder do
         {label, new_code}
       end)
 
-    {js_files, css_parts, assets}
+    %{compiled | scripts: js_files}
   end
 
   defp relative_label(from_label, to_label) do
@@ -640,6 +778,41 @@ defmodule Volt.Builder do
   end
 
   defp rewrite_imports_to_labels(code, label_map, from_label, global_map) do
+    case compact_import_label_patches(code, label_map, from_label, global_map) do
+      {:ok, []} -> code
+      {:ok, patches} -> OXC.patch_string(code, patches)
+      :fallback -> rewrite_imports_to_labels_from_ast(code, label_map, from_label, global_map)
+    end
+  end
+
+  defp compact_import_label_patches(code, label_map, from_label, global_map) do
+    with {:ok, imports} <- OXC.select(code, "module.js", :import_sources),
+         {:ok, []} <- OXC.select(code, "module.js", :require_calls),
+         false <- dynamic_css_import?(imports) do
+      patches =
+        Enum.reduce(imports, [], fn %{specifier: specifier, start: start, end: end_offset}, acc ->
+          case rewrite_specifier(specifier, label_map, from_label, global_map) do
+            {:rewrite, replacement} ->
+              [%{start: start, end: end_offset, change: Jason.encode!(replacement)} | acc]
+
+            :keep ->
+              acc
+          end
+        end)
+
+      {:ok, patches}
+    else
+      _unsupported_or_invalid -> :fallback
+    end
+  end
+
+  defp dynamic_css_import?(imports) do
+    Enum.any?(imports, fn import ->
+      import.type == :dynamic and Path.extname(import.specifier) in @css_exts
+    end)
+  end
+
+  defp rewrite_imports_to_labels_from_ast(code, label_map, from_label, global_map) do
     case OXC.parse(code, "module.js") do
       {:ok, ast} ->
         patches = collect_import_label_patches(ast, label_map, from_label, global_map)
@@ -758,15 +931,46 @@ defmodule Volt.Builder do
     if Volt.HTMLEntry.html?(entry) do
       {:ok, %{scripts: scripts, styles: styles}} = Volt.HTMLEntry.extract(entry)
 
-      Enum.map(scripts, &{&1, :script, Path.basename(&1) |> Path.rootname()}) ++
-        Enum.map(styles, &{&1, :style, Path.basename(&1) |> Path.rootname()})
+      Enum.map(scripts, &{&1, :script, Naming.entry_name(&1)}) ++
+        Enum.map(styles, &{&1, :style, Naming.entry_name(&1)})
     else
       type = if Path.extname(entry) in @css_exts, do: :style, else: :script
-      entry_name = override_name || entry |> Path.basename() |> Path.rootname()
+      entry_name = Naming.entry_name(entry, override_name)
       [{entry, type, entry_name}]
     end
   end
 
+  defp unique_entry_names(entries) do
+    {entries, _used_names} =
+      Enum.map_reduce(entries, MapSet.new(), fn {entry, type, name}, used_names ->
+        unique_name = Naming.unique(name, entry, used_names)
+        {{entry, type, unique_name}, MapSet.put(used_names, unique_name)}
+      end)
+
+    entries
+  end
+
+  defp normalize_package_scopes(scopes) when is_map(scopes) or is_list(scopes) do
+    scopes
+    |> Enum.map(fn {source_root, package_dir} ->
+      {Path.expand(source_root), Path.expand(package_dir)}
+    end)
+    |> Enum.sort_by(fn {source_root, _package_dir} -> -byte_size(source_root) end)
+  end
+
+  # IIFE bundles read externals from global variables. ES module and CommonJS
+  # output keeps them as imports for the host to resolve, as Rollup does.
+  defp output_externals(ctx, build_ctx) do
+    if Keyword.get(build_ctx.bundle_opts, :format, :iife) == :iife do
+      %Volt.Builder.OutputContext{
+        external_set: ctx.external,
+        external_globals: ctx.external_globals
+      }
+    else
+      %Volt.Builder.OutputContext{external_imports: ctx.external}
+    end
+  end
+
   defp normalize_external(externals) when is_map(externals) do
     set = externals |> Map.keys() |> MapSet.new()
     {set, externals}
@@ -790,20 +994,53 @@ defmodule Volt.Builder do
   defp to_string_or_nil(value), do: to_string(value)
 
   defp finalize_build_results(results) do
-    case Enum.split_with(results, &match?({:ok, _}, &1)) do
-      {[{:ok, single}], []} -> {:ok, single}
-      {successes, []} when successes != [] -> {:ok, merge_build_results(successes)}
-      {_, [first_error | _]} -> first_error
-    end
-  end
+    Enum.reduce_while(
+      results,
+      {:ok, %Volt.Builder.Result{}, []},
+      fn
+        {:error, _} = error, _acc ->
+          {:halt, error}
 
-  defp merge_build_results(results) do
-    Enum.reduce(results, %Volt.Builder.Result{}, fn {:ok, result}, acc ->
-      %Volt.Builder.Result{
-        js: [result.js | acc.js],
-        css: result.css || acc.css,
-        manifest: Map.merge(acc.manifest, result.manifest)
-      }
-    end)
+        {:ok, result, plan}, {:ok, acc, artifact_groups} ->
+          conflicts = Volt.Builder.ManifestEntry.conflicts(result.manifest, acc.manifest)
+
+          with [] <- conflicts do
+            merged = %Volt.Builder.Result{
+              js: [result.js | acc.js],
+              css: result.css || acc.css,
+              styles: [result.styles | acc.styles],
+              chunks: [result.chunks | acc.chunks],
+              declarations: [result.declarations | acc.declarations],
+              manifest: Map.merge(acc.manifest, result.manifest)
+            }
+
+            {:cont, {:ok, merged, [plan.artifacts | artifact_groups]}}
+          else
+            keys -> {:halt, {:error, {:manifest_collision, Enum.sort(keys)}}}
+          end
+      end
+    )
+    |> case do
+      {:ok, result, artifact_groups} ->
+        js =
+          case result.js |> Enum.reverse() |> List.flatten() do
+            [single] -> single
+            entries -> entries
+          end
+
+        with {:ok, plan} <- Volt.Builder.Plan.new(List.flatten(artifact_groups)) do
+          {:ok,
+           %{
+             result
+             | js: js,
+               styles: result.styles |> Enum.reverse() |> List.flatten() |> Enum.uniq(),
+               chunks: result.chunks |> Enum.reverse() |> List.flatten(),
+               declarations: result.declarations |> Enum.reverse() |> List.flatten()
+           }, plan}
+        end
+
+      {:error, _} = error ->
+        error
+    end
   end
 end
diff --git a/lib/volt/builder/artifact.ex b/lib/volt/builder/artifact.ex
new file mode 100644
index 0000000..5d61222
--- /dev/null
+++ b/lib/volt/builder/artifact.ex
@@ -0,0 +1,33 @@
+defmodule Volt.Builder.Artifact do
+  @moduledoc false
+
+  @enforce_keys [:file, :content]
+  defstruct [:file, :content]
+
+  @type t :: %__MODULE__{file: String.t(), content: binary()}
+
+  @spec asset(String.t(), binary()) :: t()
+  def asset(source_path, content) do
+    ext = Path.extname(source_path)
+    name = Path.basename(source_path, ext)
+    hash = Volt.Builder.Naming.hash(content)
+    %__MODULE__{file: "#{name}-#{hash}#{ext}", content: content}
+  end
+
+  @spec javascript(String.t(), binary(), binary() | nil, keyword()) :: [t()]
+  def javascript(filename, code, sourcemap, opts \\ []) do
+    code =
+      if sourcemap && !Keyword.get(opts, :hidden, false) do
+        code <> "\n//# sourceMappingURL=#{filename}.map\n"
+      else
+        code
+      end
+
+    script = %__MODULE__{file: filename, content: code}
+
+    case sourcemap do
+      nil -> [script]
+      map -> [script, %__MODULE__{file: "#{filename}.map", content: map}]
+    end
+  end
+end
diff --git a/lib/volt/builder/asset.ex b/lib/volt/builder/asset.ex
new file mode 100644
index 0000000..e675a12
--- /dev/null
+++ b/lib/volt/builder/asset.ex
@@ -0,0 +1,8 @@
+defmodule Volt.Builder.Asset do
+  @moduledoc "Metadata for one asset emitted by a production build."
+
+  @enforce_keys [:src, :file]
+  defstruct [:src, :file]
+
+  @type t :: %__MODULE__{src: String.t(), file: String.t()}
+end
diff --git a/lib/volt/builder/context/build.ex b/lib/volt/builder/build_context.ex
similarity index 92%
rename from lib/volt/builder/context/build.ex
rename to lib/volt/builder/build_context.ex
index 77e2cb8..3dfe08f 100644
--- a/lib/volt/builder/context/build.ex
+++ b/lib/volt/builder/build_context.ex
@@ -8,6 +8,7 @@ defmodule Volt.Builder.BuildContext do
             ctx: nil,
             asset_url_prefix: Volt.Paths.prefix(),
             code_splitting: true,
+            declarations: false,
             sourcemap_hidden: false,
             chunks: %{}
 end
diff --git a/lib/volt/builder/bundle.ex b/lib/volt/builder/bundle.ex
index 6063f97..7b6c8f4 100644
--- a/lib/volt/builder/bundle.ex
+++ b/lib/volt/builder/bundle.ex
@@ -17,6 +17,6 @@ defmodule Volt.Builder.Bundle do
           sourcemap: String.t() | nil,
           files: [Path.t()],
           css: String.t() | nil,
-          assets: [term()]
+          assets: [Volt.Builder.Asset.t()]
         }
 end
diff --git a/lib/volt/builder/collector.ex b/lib/volt/builder/collector.ex
index c2c99ce..f06acc9 100644
--- a/lib/volt/builder/collector.ex
+++ b/lib/volt/builder/collector.ex
@@ -1,7 +1,7 @@
 defmodule Volt.Builder.Collector do
   @moduledoc "Walks the dependency graph from entry files, collecting modules and workers."
 
-  alias Volt.Builder.Resolver
+  alias Volt.Builder.{Naming, Resolver}
 
   @doc """
   Walk the dependency graph from an entry file.
@@ -12,7 +12,7 @@ defmodule Volt.Builder.Collector do
   - `workers` is `%{importer_path => %{specifier => worker_abs_path}}`
   """
   def collect(entry_path, ctx) do
-    label = Path.basename(entry_path)
+    label = entry_path |> Path.basename() |> Naming.file_path()
 
     state = %Volt.Builder.Collector.State{
       ctx: ctx,
@@ -76,7 +76,8 @@ defmodule Volt.Builder.Collector do
   end
 
   defp read_module(module_id, plugins) do
-    with nil <- read_embedded_module(module_id, plugins),
+    with false <- Volt.Builder.Resolver.empty_module?(module_id),
+         nil <- read_embedded_module(module_id, plugins),
          nil <- read_plugin_module(module_id, plugins) do
       path = module_path(module_id)
 
@@ -84,6 +85,9 @@ defmodule Volt.Builder.Collector do
         {:ok, source} -> {:ok, source, nil}
         error -> error
       end
+    else
+      true -> {:ok, "export {};\n", nil}
+      other -> other
     end
   end
 
@@ -305,8 +309,8 @@ defmodule Volt.Builder.Collector do
   end
 
   defp unique_label(_specifier, resolved_path, state) do
-    base_label = module_label(resolved_path, state.root)
-    label = deduplicate_label(base_label, resolved_path, state.used_labels)
+    base_label = Naming.module_label(resolved_path, state.root)
+    label = Naming.unique(base_label, resolved_path, state.used_labels)
 
     state = %{
       state
@@ -317,61 +321,6 @@ defmodule Volt.Builder.Collector do
     {label, state}
   end
 
-  defp module_label(resolved_path, root) do
-    {path, query} = Volt.URL.split_query(resolved_path)
-    [relative_path | rest] = path |> String.split("/node_modules/") |> Enum.reverse()
-
-    label =
-      if rest != [] do
-        relative_path
-      else
-        relative = Path.relative_to(path, root)
-
-        if Path.type(relative) == :absolute do
-          "_external/" <>
-            Path.basename(Path.dirname(path)) <> "/" <> Path.basename(path)
-        else
-          relative
-        end
-      end
-      |> with_query_suffix(query)
-
-    cond do
-      Path.extname(label) == ".json" -> Path.rootname(label) <> ".json.js"
-      Path.extname(label) in Volt.JS.Extensions.css() -> label <> ".js"
-      query != "" -> label <> ".js"
-      true -> label
-    end
-  end
-
-  defp with_query_suffix(label, ""), do: label
-
-  defp with_query_suffix(label, query) do
-    suffix =
-      query
-      |> URI.decode_query()
-      |> Map.keys()
-      |> Enum.sort()
-      |> Enum.join("-")
-
-    label <> "." <> suffix
-  end
-
-  defp deduplicate_label(label, resolved_path, used) do
-    if MapSet.member?(used, label) do
-      parent = resolved_path |> Path.dirname() |> Path.basename()
-      candidate = parent <> "/" <> label
-
-      if MapSet.member?(used, candidate) do
-        deduplicate_label(candidate <> "_2", resolved_path, used)
-      else
-        candidate
-      end
-    else
-      label
-    end
-  end
-
   defp split_imports(typed_imports) do
     {statics, dynamics} =
       Enum.reduce(typed_imports, {[], []}, fn
diff --git a/lib/volt/builder/compiled.ex b/lib/volt/builder/compiled.ex
new file mode 100644
index 0000000..35561d7
--- /dev/null
+++ b/lib/volt/builder/compiled.ex
@@ -0,0 +1,5 @@
+defmodule Volt.Builder.Compiled do
+  @moduledoc "Compiled modules and prepared binary assets before bundling."
+
+  defstruct scripts: [], styles: [], assets: [], artifacts: []
+end
diff --git a/lib/volt/builder/context.ex b/lib/volt/builder/context.ex
index 4dc4254..f0089e9 100644
--- a/lib/volt/builder/context.ex
+++ b/lib/volt/builder/context.ex
@@ -3,6 +3,7 @@ defmodule Volt.Builder.Context do
 
   defstruct node_modules: nil,
             resolve_dirs: [],
+            package_scopes: [],
             aliases: %{},
             plugins: [],
             external: MapSet.new(),
@@ -15,4 +16,22 @@ defmodule Volt.Builder.Context do
             asset_url_prefix: Volt.Paths.prefix(),
             asset_outdir: nil,
             asset_root: nil
+
+  @type t :: %__MODULE__{
+          node_modules: Path.t() | nil,
+          resolve_dirs: [Path.t()],
+          package_scopes: list(),
+          aliases: %{String.t() => String.t()},
+          plugins: [module() | {module(), keyword()}],
+          external: MapSet.t(String.t()),
+          external_globals: %{String.t() => String.t()},
+          loaders: map(),
+          module_types: map(),
+          import_source: String.t() | nil,
+          target: String.t(),
+          define: map(),
+          asset_url_prefix: String.t(),
+          asset_outdir: Path.t() | nil,
+          asset_root: Path.t() | nil
+        }
 end
diff --git a/lib/volt/builder/css.ex b/lib/volt/builder/css.ex
index 71b025d..711db38 100644
--- a/lib/volt/builder/css.ex
+++ b/lib/volt/builder/css.ex
@@ -1,6 +1,42 @@
 defmodule Volt.Builder.CSS do
   @moduledoc false
 
+  def prepare_parts(css_parts, bundle_opts) do
+    css_parts
+    |> Enum.reduce_while({:ok, []}, fn part, {:ok, acc} ->
+      case prepare_part(part, bundle_opts) do
+        {:ok, prepared} -> {:cont, {:ok, [prepared | acc]}}
+        {:error, _} = error -> {:halt, error}
+      end
+    end)
+    |> case do
+      {:ok, reversed} ->
+        parts = Enum.reverse(reversed)
+
+        {:ok,
+         %Volt.Builder.CSS.Prepared{
+           code: Enum.map_join(parts, "\n", & &1.code),
+           assets: parts |> Enum.flat_map(& &1.assets) |> Enum.uniq(),
+           artifacts: Enum.flat_map(parts, & &1.artifacts)
+         }}
+
+      {:error, _} = error ->
+        error
+    end
+  end
+
+  def prepare_part({source_path, css}, bundle_opts) do
+    with {:ok, css} <- Volt.CSS.Imports.inline(css, source_path, bundle_opts) do
+      Volt.CSS.AssetURLRewriter.prepare(css, source_path,
+        prefix: Keyword.get(bundle_opts, :asset_url_prefix, Volt.Paths.prefix()),
+        root: Keyword.get(bundle_opts, :root)
+      )
+    end
+  end
+
+  def prepare_part(css, _bundle_opts),
+    do: {:ok, %Volt.Builder.CSS.Prepared{code: css, assets: [], artifacts: []}}
+
   def bundle_parts(css_parts, fun) when is_function(fun, 1) do
     css_parts
     |> Enum.reduce_while({:ok, [], []}, fn css_part, {:ok, code_parts, assets} ->
diff --git a/lib/volt/builder/css/prepared.ex b/lib/volt/builder/css/prepared.ex
new file mode 100644
index 0000000..0eda5dd
--- /dev/null
+++ b/lib/volt/builder/css/prepared.ex
@@ -0,0 +1,12 @@
+defmodule Volt.Builder.CSS.Prepared do
+  @moduledoc false
+
+  @enforce_keys [:code, :assets, :artifacts]
+  defstruct [:code, :assets, :artifacts]
+
+  @type t :: %__MODULE__{
+          code: String.t(),
+          assets: [Volt.Builder.Asset.t()],
+          artifacts: [Volt.Builder.Artifact.t()]
+        }
+end
diff --git a/lib/volt/builder/declarations.ex b/lib/volt/builder/declarations.ex
new file mode 100644
index 0000000..0f2e5a0
--- /dev/null
+++ b/lib/volt/builder/declarations.ex
@@ -0,0 +1,618 @@
+defmodule Volt.Builder.Declarations do
+  @moduledoc """
+  Writes the type declarations of a library entry as one `.d.ts`.
+
+  Each TypeScript module of the entry's graph is emitted through OXC's isolated
+  declarations, which need explicit types on exported declarations and report
+  the ones they cannot infer; a plugin-owned module, such as a `.vue` file, is
+  declared by its plugin. The declarations are then bundled the way
+  `rollup-plugin-dts` bundles them: the graph is walked from the entry along
+  the declarations' own imports, so modules that only hold types are included;
+  only the declarations the entry's exports reach are kept, along with ambient
+  declarations such as `declare module`; imports of other packages are hoisted
+  and merged; and two modules declaring the same name are told apart by
+  renaming the one further from the entry.
+
+  Declarations are module-scoped, so names resolve at the top level of each
+  module: an identifier is the module's own declaration of that name, or what
+  the module imports under that name. Property names, type parameters and
+  parameters are left alone.
+  """
+
+  alias Volt.Builder.Resolver
+
+  @declarations [
+    :ts_type_alias_declaration,
+    :ts_interface_declaration,
+    :class_declaration,
+    :function_declaration,
+    :ts_declare_function,
+    :ts_enum_declaration,
+    :ts_module_declaration
+  ]
+
+  @doc """
+  Bundle the declarations of the module at `entry` into one `.d.ts` source.
+
+  Returns `{:error, {:declarations, path, reason}}` when a module's declarations
+  cannot be emitted (`reason` is then the emitter's diagnostics) or hold a
+  construct the bundler does not handle (`reason` is then a message).
+  """
+  @spec bundle(Path.t(), Volt.Builder.Context.t()) :: {:ok, String.t()} | {:error, term()}
+  def bundle(entry, ctx) do
+    entry = Path.expand(entry)
+
+    with {:ok, modules} <- collect(entry, ctx, %{}) do
+      bundle_modules(entry, modules)
+    end
+  end
+
+  # ── Collecting ────────────────────────────────────────────────────
+
+  # `modules` maps a path to its declarations: the imports of other packages
+  # as written, the bindings imported from project modules, the statements,
+  # and the exports.
+  defp collect(path, _ctx, modules) when is_map_key(modules, path), do: {:ok, modules}
+
+  defp collect(path, ctx, modules) do
+    with {:ok, dts} <- declaration_source(path, ctx),
+         {:ok, ast} <- OXC.parse(dts, Path.basename(path) <> ".d.ts"),
+         {:ok, module} <- read_module(path, dts, ast, ctx) do
+      Enum.reduce_while(module.sources, {:ok, Map.put(modules, path, module)}, fn dep,
+                                                                                  {:ok, acc} ->
+        case collect(dep, ctx, acc) do
+          {:ok, acc} -> {:cont, {:ok, acc}}
+          error -> {:halt, error}
+        end
+      end)
+    else
+      {:error, {:declarations, _path, _reason}} = error -> error
+      {:error, reason} -> {:error, {:declarations, path, reason}}
+    end
+  end
+
+  defp declaration_source(path, ctx) do
+    with {:ok, source} <- File.read(path) do
+      case Volt.PluginRunner.declaration(ctx.plugins, path, source, []) do
+        {:ok, dts} -> {:ok, dts}
+        {:error, reason} -> {:error, reason}
+        nil -> OXC.isolated_declarations(source, Path.basename(path))
+      end
+    end
+  end
+
+  defp read_module(path, dts, ast, ctx) do
+    module = %{
+      path: path,
+      external_imports: [],
+      imports: %{},
+      statements: [],
+      exports: %{},
+      export_all: [],
+      sources: []
+    }
+
+    ast.body
+    |> Enum.reduce_while({:ok, module, 0}, fn node, {:ok, module, previous_end} ->
+      case read_statement(node, {dts, previous_end}, ctx, module) do
+        {:ok, module} -> {:cont, {:ok, module, node.end}}
+        {:error, message} -> {:halt, {:error, {:declarations, path, message}}}
+      end
+    end)
+    |> case do
+      {:ok, module, _end} ->
+        {:ok,
+         %{
+           module
+           | statements: Enum.reverse(module.statements),
+             external_imports: Enum.reverse(module.external_imports),
+             sources: module.sources |> Enum.reverse() |> Enum.uniq()
+         }}
+
+      error ->
+        error
+    end
+  end
+
+  defp read_statement(%{type: :import_declaration} = node, {dts, _previous_end}, ctx, module) do
+    case resolve_source(node.source.value, module.path, ctx) do
+      {:project, dep} ->
+        imports =
+          Enum.reduce(node.specifiers, module.imports, fn specifier, imports ->
+            Map.put(imports, specifier.local.name, {dep, imported_name(specifier)})
+          end)
+
+        {:ok, %{module | imports: imports, sources: [dep | module.sources]}}
+
+      :external ->
+        {:ok, %{module | external_imports: [slice(dts, node) | module.external_imports]}}
+    end
+  end
+
+  defp read_statement(%{type: :export_all_declaration} = node, _dts, ctx, module) do
+    case {node.exported, resolve_source(node.source.value, module.path, ctx)} do
+      {nil, {:project, dep}} ->
+        {:ok, %{module | export_all: [dep | module.export_all], sources: [dep | module.sources]}}
+
+      {nil, :external} ->
+        {:error,
+         "`export * from #{inspect(node.source.value)}` of another package is not bundled"}
+
+      {%{name: name}, _} ->
+        {:error, "`export * as #{name}` is not bundled; import the module and export it"}
+    end
+  end
+
+  # `export { a, b as c }`, with or without `from`.
+  defp read_statement(
+         %{type: :export_named_declaration, declaration: nil} = node,
+         _dts,
+         ctx,
+         module
+       ) do
+    with {:ok, from} <- export_source(node, module.path, ctx) do
+      exports =
+        Enum.reduce(node.specifiers, module.exports, fn specifier, exports ->
+          target =
+            if from,
+              do: {:import, from, specifier.local.name},
+              else: {:binding, specifier.local.name}
+
+          Map.put(exports, specifier.exported.name, target)
+        end)
+
+      {:ok, %{module | exports: exports, sources: List.wrap(from) ++ module.sources}}
+    end
+  end
+
+  defp read_statement(
+         %{type: :export_named_declaration, declaration: declaration} = node,
+         dts,
+         _ctx,
+         module
+       ) do
+    statement = statement(module.path, dts, declaration, node)
+    exports = Enum.reduce(statement.names, module.exports, &Map.put(&2, &1, {:binding, &1}))
+    {:ok, %{module | statements: [statement | module.statements], exports: exports}}
+  end
+
+  defp read_statement(
+         %{type: :export_default_declaration, declaration: %{type: :identifier, name: name}},
+         _dts,
+         _ctx,
+         module
+       ) do
+    {:ok, %{module | exports: Map.put(module.exports, "default", {:binding, name})}}
+  end
+
+  defp read_statement(
+         %{type: :export_default_declaration, declaration: declaration} = node,
+         dts,
+         _ctx,
+         module
+       ) do
+    case statement(module.path, dts, declaration, node) do
+      %{names: [name]} = statement ->
+        exports = Map.put(module.exports, "default", {:binding, name})
+        {:ok, %{module | statements: [statement | module.statements], exports: exports}}
+
+      _anonymous ->
+        {:error, "an anonymous `export default` cannot be referenced from the bundle; name it"}
+    end
+  end
+
+  defp read_statement(node, dts, _ctx, module) do
+    {:ok, %{module | statements: [statement(module.path, dts, node, node) | module.statements]}}
+  end
+
+  defp export_source(%{source: nil}, _path, _ctx), do: {:ok, nil}
+
+  defp export_source(%{source: %{value: specifier}}, path, ctx) do
+    case resolve_source(specifier, path, ctx) do
+      {:project, dep} ->
+        {:ok, dep}
+
+      :external ->
+        {:error, "`export { ... } from #{inspect(specifier)}` of another package is not bundled"}
+    end
+  end
+
+  defp imported_name(%{type: :import_default_specifier}), do: "default"
+  defp imported_name(%{type: :import_namespace_specifier}), do: "*"
+  defp imported_name(%{imported: imported}), do: imported.name
+
+  # A module of the project is bundled; anything that resolves into a package,
+  # or is external to the build, stays an import for the consumer to resolve.
+  defp resolve_source(specifier, importer, ctx) do
+    case Resolver.resolve(specifier, importer, ctx) do
+      {:ok, resolved} ->
+        {resolved_path, _query} = Volt.URL.split_query(resolved)
+
+        if Resolver.inside_node_modules?(resolved) or not File.regular?(resolved_path),
+          do: :external,
+          else: {:project, Path.expand(resolved_path)}
+
+      _skip_or_error ->
+        :external
+    end
+  end
+
+  # A top-level statement: its text, the names it declares and the
+  # identifiers it refers to, with offsets into the text.
+  #
+  # The text is the declaration without its `export`, led by the comments
+  # between the previous statement and this one, which hold its JSDoc. A
+  # declaration that `export default` left without `declare` gets it back, as
+  # it no longer has the `export` that implied it.
+  defp statement(path, {dts, previous_end}, node, outer) do
+    lead = dts |> binary_part(previous_end, outer.start - previous_end) |> String.trim()
+    declare = if implied_declare?(node), do: "declare ", else: ""
+    prefix = if lead == "", do: declare, else: lead <> "\n" <> declare
+
+    %{
+      module: path,
+      text: prefix <> slice(dts, node),
+      names: declared_names(node),
+      references: references(node, node.start - byte_size(prefix))
+    }
+  end
+
+  defp implied_declare?(%{type: type, declare: false})
+       when type in [
+              :class_declaration,
+              :function_declaration,
+              :ts_declare_function,
+              :variable_declaration,
+              :ts_enum_declaration
+            ],
+       do: true
+
+  defp implied_declare?(_node), do: false
+
+  defp slice(source, %{start: start, end: finish}), do: binary_part(source, start, finish - start)
+
+  # ── Names ─────────────────────────────────────────────────────────
+
+  defp declared_names(%{type: :variable_declaration, declarations: declarations}),
+    do: for(%{id: %{type: :identifier, name: name}} <- declarations, do: name)
+
+  defp declared_names(%{type: type, id: %{type: :identifier, name: name}})
+       when type in @declarations,
+       do: [name]
+
+  defp declared_names(_node), do: []
+
+  # Names the statement binds itself, property names, type parameters,
+  # parameters and member accesses are not references.
+  defp references(node, base) do
+    {_node, {references, bound}} =
+      OXC.postwalk(node, {[], MapSet.new()}, fn
+        %{type: :identifier, name: name, start: start, end: finish} = id, {refs, bound} ->
+          {id, {[%{start: start - base, end: finish - base, name: name} | refs], bound}}
+
+        other, {refs, bound} ->
+          {other, {refs, bind(other, bound)}}
+      end)
+
+    references
+    |> Enum.reject(&MapSet.member?(bound, &1.start + base))
+    |> Enum.sort_by(& &1.start)
+  end
+
+  defp bind(%{type: :ts_type_parameter, name: %{start: start}}, bound),
+    do: MapSet.put(bound, start)
+
+  defp bind(%{type: :ts_qualified_name, right: %{start: start}}, bound),
+    do: MapSet.put(bound, start)
+
+  defp bind(%{type: :ts_enum_member, id: %{start: start}}, bound), do: MapSet.put(bound, start)
+
+  defp bind(%{type: :variable_declarator, id: %{start: start}}, bound),
+    do: MapSet.put(bound, start)
+
+  defp bind(%{type: :member_expression, computed: false, property: %{start: start}}, bound),
+    do: MapSet.put(bound, start)
+
+  defp bind(%{computed: false, key: %{type: :identifier, start: start}}, bound),
+    do: MapSet.put(bound, start)
+
+  defp bind(%{type: type, id: %{type: :identifier, start: start}} = node, bound)
+       when type in @declarations,
+       do: node |> Map.delete(:id) |> bind(MapSet.put(bound, start))
+
+  # Parameters bind their names: `(items: string[])` refers to nothing.
+  defp bind(%{params: params}, bound) when is_list(params) do
+    Enum.reduce(params, bound, fn
+      %{type: :identifier, start: start}, bound -> MapSet.put(bound, start)
+      %{type: :assignment_pattern, left: %{start: start}}, bound -> MapSet.put(bound, start)
+      %{type: :rest_element, argument: %{start: start}}, bound -> MapSet.put(bound, start)
+      _pattern, bound -> bound
+    end)
+  end
+
+  defp bind(_node, bound), do: bound
+
+  # ── Bundling ──────────────────────────────────────────────────────
+
+  defp bundle_modules(entry, modules) do
+    declared = declared_index(modules)
+
+    with {:ok, entry_exports} <- exports_of(entry, modules, MapSet.new()),
+         roots = for({_exported, target} <- entry_exports, do: target),
+         {:ok, reached} <- reach(roots, modules, declared, MapSet.new()) do
+      statements = emitted_statements(modules, reached, entry)
+      renames = renames(statements, entry)
+      paths = statements |> Enum.map(& &1.module) |> Enum.uniq()
+
+      parts = [
+        external_imports(paths, modules),
+        Enum.map_join(statements, "\n", &rewrite(&1, modules, renames)),
+        export_list(entry_exports, renames)
+      ]
+
+      {:ok, Enum.map_join(Enum.reject(parts, &(&1 == "")), "\n", & &1) <> "\n"}
+    end
+  end
+
+  # What a module exports, as `%{exported_name => {module, declared_name}}`,
+  # following re-exports and `export *` to the declaring module.
+  defp exports_of(path, modules, visiting) do
+    if MapSet.member?(visiting, path) do
+      {:ok, %{}}
+    else
+      module = Map.fetch!(modules, path)
+      visiting = MapSet.put(visiting, path)
+
+      with {:ok, starred} <- star_exports(module.export_all, modules, visiting) do
+        named_exports(module, modules, visiting, starred)
+      end
+    end
+  end
+
+  defp named_exports(module, modules, visiting, acc) do
+    Enum.reduce_while(module.exports, {:ok, acc}, fn {exported, target}, {:ok, acc} ->
+      case resolve_target(target, module, modules, visiting) do
+        {:ok, resolved} -> {:cont, {:ok, Map.put(acc, exported, resolved)}}
+        error -> {:halt, error}
+      end
+    end)
+  end
+
+  defp star_exports(sources, modules, visiting) do
+    Enum.reduce_while(sources, {:ok, %{}}, fn dep, {:ok, acc} ->
+      case exports_of(dep, modules, visiting) do
+        {:ok, exports} -> {:cont, {:ok, Map.merge(acc, Map.delete(exports, "default"))}}
+        error -> {:halt, error}
+      end
+    end)
+  end
+
+  defp resolve_target({:import, dep, name}, module, modules, visiting),
+    do: resolve_imported(module.path, dep, name, modules, visiting)
+
+  defp resolve_target({:binding, name}, module, modules, visiting) do
+    case resolve_name(module, name, modules, visiting) do
+      {:ok, target} ->
+        {:ok, target}
+
+      :none ->
+        {:error,
+         {:declarations, module.path, "`#{name}` is exported but not declared or imported"}}
+
+      error ->
+        error
+    end
+  end
+
+  # A name at a module's top level is its own declaration or an import.
+  defp resolve_name(module, name, modules, visiting \\ MapSet.new()) do
+    cond do
+      Enum.any?(module.statements, &(name in &1.names)) ->
+        {:ok, {module.path, name}}
+
+      match?(%{^name => _}, module.imports) ->
+        {dep, imported} = module.imports[name]
+        resolve_imported(module.path, dep, imported, modules, visiting)
+
+      true ->
+        :none
+    end
+  end
+
+  defp resolve_imported(importer, _dep, "*", _modules, _visiting) do
+    {:error,
+     {:declarations, importer,
+      "`import * as` of a project module is not bundled; import its names"}}
+  end
+
+  defp resolve_imported(importer, dep, name, modules, visiting) do
+    with {:ok, exports} <- exports_of(dep, modules, visiting) do
+      case exports do
+        %{^name => resolved} ->
+          {:ok, resolved}
+
+        _ ->
+          {:error,
+           {:declarations, importer, "#{Path.relative_to_cwd(dep)} does not export `#{name}`"}}
+      end
+    end
+  end
+
+  # `%{{module, name} => [{statement_index, statement}]}`: an interface merged
+  # over several statements, or an overloaded function, is declared by all of
+  # them.
+  defp declared_index(modules) do
+    for {path, module} <- modules,
+        {statement, index} <- Enum.with_index(module.statements),
+        name <- statement.names,
+        reduce: %{} do
+      acc -> Map.update(acc, {path, name}, [{index, statement}], &[{index, statement} | &1])
+    end
+  end
+
+  # The statements reachable from `roots` through references, as a set of
+  # `{module, statement_index}`.
+  defp reach([], _modules, _declared, reached), do: {:ok, reached}
+
+  defp reach([{path, name} | rest], modules, declared, reached) do
+    pending =
+      declared
+      |> Map.get({path, name}, [])
+      |> Enum.reject(fn {index, _statement} -> MapSet.member?(reached, {path, index}) end)
+
+    reached =
+      Enum.reduce(pending, reached, fn {index, _statement}, acc ->
+        MapSet.put(acc, {path, index})
+      end)
+
+    pending
+    |> Enum.reduce_while({:ok, rest}, fn {_index, statement}, {:ok, rest} ->
+      case reference_targets(statement, modules) do
+        {:ok, targets} -> {:cont, {:ok, Enum.reduce(targets, rest, &[&1 | &2])}}
+        error -> {:halt, error}
+      end
+    end)
+    |> case do
+      {:ok, rest} -> reach(rest, modules, declared, reached)
+      error -> error
+    end
+  end
+
+  # Where a statement's references lead. Names that are neither declared nor
+  # imported, such as globals and the lib's types, lead nowhere.
+  defp reference_targets(statement, modules) do
+    module = modules[statement.module]
+
+    statement.references
+    |> Enum.map(& &1.name)
+    |> Enum.uniq()
+    |> Enum.reduce_while({:ok, []}, fn name, {:ok, acc} ->
+      case resolve_name(module, name, modules) do
+        {:ok, target} -> {:cont, {:ok, [target | acc]}}
+        :none -> {:cont, {:ok, acc}}
+        error -> {:halt, error}
+      end
+    end)
+  end
+
+  # Reached statements and ambient ones, dependencies before dependents with
+  # the entry last, and a module's statements in their own order.
+  defp emitted_statements(modules, reached, entry) do
+    entry
+    |> module_order(modules, {[], MapSet.new()})
+    |> elem(0)
+    |> Enum.reverse()
+    |> Enum.flat_map(fn path ->
+      modules[path].statements
+      |> Enum.with_index()
+      |> Enum.filter(fn {statement, index} ->
+        statement.names == [] or MapSet.member?(reached, {path, index})
+      end)
+      |> Enum.map(fn {statement, _index} -> statement end)
+    end)
+  end
+
+  defp module_order(path, modules, {order, seen}) do
+    if MapSet.member?(seen, path) do
+      {order, seen}
+    else
+      {order, seen} =
+        Enum.reduce(
+          modules[path].sources,
+          {order, MapSet.put(seen, path)},
+          &module_order(&1, modules, &2)
+        )
+
+      {[path | order], seen}
+    end
+  end
+
+  # Names declared by more than one module keep their spelling in the module
+  # nearest the entry, in emission order, and gain a `$1`, `$2`, ... elsewhere.
+  defp renames(statements, entry) do
+    statements
+    |> Enum.sort_by(&(&1.module != entry))
+    |> Enum.flat_map(&Enum.map(&1.names, fn name -> {&1.module, name} end))
+    |> Enum.uniq()
+    |> Enum.reduce({%{}, MapSet.new()}, fn {module, name}, {renames, taken} ->
+      if MapSet.member?(taken, name) do
+        renamed =
+          Enum.find(
+            Stream.map(Stream.iterate(1, &(&1 + 1)), &"#{name}$#{&1}"),
+            &(not MapSet.member?(taken, &1))
+          )
+
+        {Map.put(renames, {module, name}, renamed), MapSet.put(taken, renamed)}
+      else
+        {renames, MapSet.put(taken, name)}
+      end
+    end)
+    |> elem(0)
+  end
+
+  defp emitted_name({module, name}, renames), do: Map.get(renames, {module, name}, name)
+
+  # A statement's text with every identifier that resolves to a declaration
+  # spelled as that declaration is emitted, and its own names likewise.
+  defp rewrite(statement, modules, renames) do
+    module = modules[statement.module]
+
+    reference_patches =
+      Enum.flat_map(statement.references, fn reference ->
+        with {:ok, target} <- resolve_name(module, reference.name, modules),
+             emitted when emitted != reference.name <- emitted_name(target, renames) do
+          [Volt.JS.Patch.new(reference.start, reference.end, emitted)]
+        else
+          _unresolved_or_unchanged -> []
+        end
+      end)
+
+    own_patches =
+      Enum.flat_map(statement.names, fn name ->
+        case Map.fetch(renames, {statement.module, name}) do
+          {:ok, renamed} -> declaration_name_patches(statement.text, name, renamed)
+          :error -> []
+        end
+      end)
+
+    OXC.patch_string(statement.text, reference_patches ++ own_patches)
+  end
+
+  # The binding identifier of a renamed declaration, found by parsing the
+  # statement again: it was excluded from the references on purpose.
+  defp declaration_name_patches(text, name, renamed) do
+    {:ok, ast} = OXC.parse(text, "statement.d.ts")
+
+    for node <- ast.body,
+        %{start: start, end: finish} <- declaration_ids(node),
+        binary_part(text, start, finish - start) == name,
+        do: Volt.JS.Patch.new(start, finish, renamed)
+  end
+
+  defp declaration_ids(%{type: :variable_declaration, declarations: declarations}),
+    do: Enum.map(declarations, & &1.id)
+
+  defp declaration_ids(%{id: %{type: :identifier} = id}), do: [id]
+  defp declaration_ids(_node), do: []
+
+  # Imports of other packages, as written, in the order the modules are
+  # emitted, without repeats.
+  defp external_imports(paths, modules) do
+    paths
+    |> Enum.flat_map(&modules[&1].external_imports)
+    |> Enum.uniq()
+    |> Enum.join("\n")
+  end
+
+  defp export_list(entry_exports, renames) do
+    specifiers =
+      entry_exports
+      |> Enum.sort()
+      |> Enum.map(fn {exported, target} ->
+        emitted = emitted_name(target, renames)
+        if emitted == exported, do: emitted, else: "#{emitted} as #{exported}"
+      end)
+
+    if specifiers == [], do: "", else: "export { #{Enum.join(specifiers, ", ")} };"
+  end
+end
diff --git a/lib/volt/builder/collector/dependencies.ex b/lib/volt/builder/dependencies.ex
similarity index 100%
rename from lib/volt/builder/collector/dependencies.ex
rename to lib/volt/builder/dependencies.ex
diff --git a/lib/volt/builder/externals.ex b/lib/volt/builder/externals.ex
index e8f0a94..419055d 100644
--- a/lib/volt/builder/externals.ex
+++ b/lib/volt/builder/externals.ex
@@ -1,5 +1,5 @@
 defmodule Volt.Builder.Externals do
-  @moduledoc "Rewrite external imports into global variable access for production builds."
+  @moduledoc "Rewrite external imports into global variable access for IIFE production builds."
 
   @doc """
   Rewrite external import declarations into direct global access.
diff --git a/lib/volt/builder/manifest_entry.ex b/lib/volt/builder/manifest_entry.ex
index d436718..bd5fb5f 100644
--- a/lib/volt/builder/manifest_entry.ex
+++ b/lib/volt/builder/manifest_entry.ex
@@ -10,11 +10,59 @@ defmodule Volt.Builder.ManifestEntry do
             css: [],
             assets: []
 
+  @type t :: %__MODULE__{
+          file: String.t(),
+          src: String.t(),
+          isEntry: boolean(),
+          imports: [String.t()],
+          dynamicImports: [String.t()],
+          css: [String.t()],
+          assets: [String.t()]
+        }
+
+  @doc "Return conflicting identities; identical shared entries are permitted."
+  def conflicts(left, right) do
+    for {key, entry} <- left,
+        Map.has_key?(right, key) and right[key] != entry,
+        do: key
+  end
+
   def js(src, file, opts \\ []) do
     %__MODULE__{src: src, file: file, isEntry: Keyword.get(opts, :entry, false)}
   end
 
   def css(src, file, assets), do: %__MODULE__{src: src, file: file, assets: assets}
-
   def asset(src, file), do: %__MODULE__{src: src, file: file}
+
+  @doc "Prefix emitted paths, preserving imports and dynamicImports as manifest keys."
+  @spec prefix_paths(t(), String.t()) :: t()
+  def prefix_paths(%__MODULE__{} = entry, prefix) do
+    %{
+      entry
+      | file: prefix_path(entry.file, prefix),
+        css: Enum.map(entry.css, &prefix_path(&1, prefix)),
+        assets: Enum.map(entry.assets, &prefix_path(&1, prefix))
+    }
+  end
+
+  @doc "Collect an entry's static stylesheet dependencies, dependencies first and deduplicated."
+  @spec stylesheets(%{String.t() => t()}, String.t()) :: [String.t()]
+  def stylesheets(manifest, key) do
+    {_seen, files} = collect_stylesheets(manifest, key, {MapSet.new(), []})
+    files |> Enum.reverse() |> Enum.uniq()
+  end
+
+  defp collect_stylesheets(manifest, key, {seen, files} = acc) do
+    if MapSet.member?(seen, key) do
+      acc
+    else
+      %__MODULE__{} = entry = Map.fetch!(manifest, key)
+      acc = {MapSet.put(seen, key), files}
+      {seen, files} = Enum.reduce(entry.imports, acc, &collect_stylesheets(manifest, &1, &2))
+      {seen, Enum.reduce(entry.css, files, &[&1 | &2])}
+    end
+  end
+
+  defp prefix_path(nil, _prefix), do: nil
+  defp prefix_path(path, prefix), do: Path.join(prefix, path)
 end
diff --git a/lib/volt/builder/naming.ex b/lib/volt/builder/naming.ex
new file mode 100644
index 0000000..bb930f0
--- /dev/null
+++ b/lib/volt/builder/naming.ex
@@ -0,0 +1,119 @@
+defmodule Volt.Builder.Naming do
+  @moduledoc false
+
+  @windows_reserved ~w(CON PRN AUX NUL COM1 COM2 COM3 COM4 COM5 COM6 COM7 COM8 COM9 LPT1 LPT2 LPT3 LPT4 LPT5 LPT6 LPT7 LPT8 LPT9)
+
+  @spec hash(iodata()) :: String.t()
+  def hash(content) do
+    :crypto.hash(:sha256, content) |> Base.encode16(case: :lower) |> binary_part(0, 8)
+  end
+
+  @spec entry_name(String.t(), String.t() | nil) :: String.t()
+  def entry_name(path, override \\ nil)
+  def entry_name(_path, override) when is_binary(override), do: file_path(override)
+  def entry_name(path, nil), do: path |> Path.basename() |> Path.rootname() |> file_path()
+
+  @spec module_label(String.t(), String.t()) :: String.t()
+  def module_label(resolved_path, root) do
+    {path, query} = Volt.URL.split_query(resolved_path)
+    [relative_path | rest] = path |> String.split("/node_modules/") |> Enum.reverse()
+
+    label =
+      if rest != [] do
+        relative_path
+      else
+        relative = Path.relative_to(path, root)
+
+        if Path.type(relative) == :absolute do
+          "_external/" <>
+            Path.basename(Path.dirname(path)) <> "/" <> Path.basename(path)
+        else
+          relative
+        end
+      end
+      |> with_query_suffix(query)
+
+    label
+    |> ensure_javascript_extension(query)
+    |> file_path()
+  end
+
+  @spec unique(String.t(), String.t(), MapSet.t(String.t())) :: String.t()
+  def unique(label, identity, used_labels) do
+    if MapSet.member?(used_labels, label) do
+      digest =
+        :crypto.hash(:sha256, identity) |> Base.encode16(case: :lower) |> binary_part(0, 10)
+
+      unique_candidate(label, digest, used_labels, 0)
+    else
+      label
+    end
+  end
+
+  @spec file_path(String.t()) :: String.t()
+  def file_path(path) do
+    path
+    |> String.replace("\\", "/")
+    |> String.split("/", trim: false)
+    |> Enum.map_join("/", &file_segment/1)
+  end
+
+  defp unique_candidate(label, digest, used_labels, attempt) do
+    suffix = if attempt == 0, do: digest, else: "#{digest}-#{attempt + 1}"
+    candidate = append_suffix(label, suffix)
+
+    if MapSet.member?(used_labels, candidate) do
+      unique_candidate(label, digest, used_labels, attempt + 1)
+    else
+      candidate
+    end
+  end
+
+  defp append_suffix(path, suffix) do
+    extension = Path.extname(path)
+    Path.rootname(path) <> "-" <> suffix <> extension
+  end
+
+  defp with_query_suffix(label, ""), do: label
+
+  defp with_query_suffix(label, query) do
+    suffix =
+      query
+      |> URI.decode_query()
+      |> Map.keys()
+      |> Enum.sort()
+      |> Enum.join("-")
+
+    label <> "." <> suffix
+  end
+
+  defp ensure_javascript_extension(label, query) do
+    cond do
+      Path.extname(label) == ".json" -> Path.rootname(label) <> ".json.js"
+      Path.extname(label) in Volt.JS.Extensions.css() -> label <> ".js"
+      query != "" -> label <> ".js"
+      true -> label
+    end
+  end
+
+  defp file_segment(segment) do
+    segment =
+      segment
+      |> String.replace(~r/[<>:"|?*\x00-\x1F]/u, "_")
+      |> String.replace(~r/[ .]+$/u, "")
+
+    cond do
+      segment == "" -> "_"
+      reserved?(segment) -> "_" <> segment
+      true -> segment
+    end
+  end
+
+  defp reserved?(segment) do
+    segment
+    |> String.split(".", parts: 2)
+    |> hd()
+    |> String.upcase()
+    |> then(&(&1 in @windows_reserved))
+  end
+end
diff --git a/lib/volt/builder/output.ex b/lib/volt/builder/output.ex
index 05d5a92..ef3d8c1 100644
--- a/lib/volt/builder/output.ex
+++ b/lib/volt/builder/output.ex
@@ -1,10 +1,15 @@
 defmodule Volt.Builder.Output do
   @moduledoc "Builds final production output files from compiled module graphs."
 
-  alias Volt.Builder.{Writer, Rewriter}
+  alias Volt.Builder.{Naming, Rewriter, Writer}
 
   @doc "Bundle modules into a single in-memory JS bundle."
-  def bundle_single(entry, {js_files, css_parts, assets}, files, build_ctx) do
+  def bundle_single(
+        entry,
+        %Volt.Builder.Compiled{scripts: js_files, styles: css_parts, assets: assets},
+        files,
+        build_ctx
+      ) do
     %{
       outdir: outdir,
       bundle_opts: bundle_opts,
@@ -13,7 +18,13 @@ defmodule Volt.Builder.Output do
     } = build_ctx
 
     js_files = Rewriter.rewrite_external_imports(js_files, ctx)
-    bundle_opts = Keyword.put(bundle_opts, :entry, Path.basename(entry))
+    entry_label = entry |> Path.basename() |> Naming.file_path()
+    entry_name = Path.rootname(entry_label)
+
+    bundle_opts =
+      bundle_opts
+      |> Keyword.put(:entry, entry_label)
+      |> put_external_imports(Rewriter.preserved_external_imports(js_files, ctx))
 
     case bundle_js_files(js_files, bundle_opts) do
       {:ok, bundle_result} ->
@@ -24,12 +35,12 @@ defmodule Volt.Builder.Output do
           Rewriter.rewrite_worker_urls(
             js_code,
             Rewriter.all_worker_map(ctx),
-            Path.rootname(Path.basename(entry))
+            entry_name
           )
 
         js_code =
           Volt.PluginRunner.render_chunk(ctx.plugins, js_code, %{
-            name: Path.rootname(Path.basename(entry)),
+            name: entry_name,
             type: :entry
           })
 
@@ -53,7 +64,25 @@ defmodule Volt.Builder.Output do
   end
 
   @doc "Bundle modules into a single JS file and write output."
-  def build_single(entry, name, {js_files, css_parts, assets}, build_ctx) do
+  def build_single(entry, name, compiled, build_ctx) do
+    with {:ok, result, plan} <- prepare_single(entry, name, compiled, build_ctx),
+         :ok <- Writer.write_plan(build_ctx.outdir, plan) do
+      {:ok, result}
+    end
+  end
+
+  @doc "Prepare one bundled entry and its stylesheet without writing output."
+  def prepare_single(
+        entry,
+        name,
+        %Volt.Builder.Compiled{
+          scripts: js_files,
+          styles: css_parts,
+          assets: assets,
+          artifacts: asset_artifacts
+        },
+        build_ctx
+      ) do
     %{
       outdir: outdir,
       hash: hash,
@@ -63,10 +92,13 @@ defmodule Volt.Builder.Output do
       asset_url_prefix: asset_url_prefix
     } = build_ctx
 
-    File.mkdir_p!(outdir)
-
     js_files = Rewriter.rewrite_external_imports(js_files, ctx)
-    bundle_opts = Keyword.put(bundle_opts, :entry, Path.basename(entry))
+    entry_label = entry |> Path.basename() |> Naming.file_path()
+
+    bundle_opts =
+      bundle_opts
+      |> Keyword.put(:entry, entry_label)
+      |> put_external_imports(Rewriter.preserved_external_imports(js_files, ctx))
 
     case bundle_js_files(js_files, bundle_opts) do
       {:ok, bundle_result} ->
@@ -80,10 +112,18 @@ defmodule Volt.Builder.Output do
           Volt.PluginRunner.render_chunk(ctx.plugins, js_code, %{name: name, type: :entry})
 
         js_filename = Writer.hashed_name(name, js_code, ".js", hash)
-        Writer.write_js(outdir, js_filename, js_code, js_sourcemap, hidden: sourcemap_hidden)
+
+        js_artifacts =
+          Volt.Builder.Artifact.javascript(js_filename, js_code, js_sourcemap,
+            hidden: sourcemap_hidden
+          )
+
         css_opts = Keyword.put(bundle_opts, :asset_url_prefix, asset_url_prefix)
 
-        with {:ok, css_result} <- Writer.write_css(css_parts, outdir, name, hash, css_opts) do
+        with {:ok, css_result, css_plan} <-
+               Writer.prepare_css(css_parts, outdir, name, hash, css_opts),
+             {:ok, plan} <-
+               Volt.Builder.Plan.new(js_artifacts ++ css_plan.artifacts ++ asset_artifacts) do
           manifest = Writer.build_manifest(name, js_filename, css_result, assets)
 
           {:ok,
@@ -93,8 +133,9 @@ defmodule Volt.Builder.Output do
                size: byte_size(js_code)
              },
              css: css_result,
+             styles: List.wrap(css_result),
              manifest: manifest
-           }}
+           }, plan}
         end
 
       {:error, _} = error ->
@@ -103,9 +144,23 @@ defmodule Volt.Builder.Output do
   end
 
   @doc "Bundle multiple ESM entries together and write Rolldown shared chunks."
-  def build_shared_entries(
+  def build_shared_entries(entries, compiled, modules, path_labels, build_ctx) do
+    with {:ok, result, plan} <-
+           prepare_shared_entries(entries, compiled, modules, path_labels, build_ctx),
+         :ok <- Writer.write_plan(build_ctx.outdir, plan) do
+      {:ok, result}
+    end
+  end
+
+  @doc "Prepare shared ESM entries and associated artifacts without writing output."
+  def prepare_shared_entries(
         entries,
-        {js_files, css_parts, assets},
+        %Volt.Builder.Compiled{
+          scripts: js_files,
+          styles: css_parts,
+          assets: assets,
+          artifacts: asset_artifacts
+        },
         modules,
         path_labels,
         build_ctx
@@ -118,8 +173,6 @@ defmodule Volt.Builder.Output do
       asset_url_prefix: asset_url_prefix
     } = build_ctx
 
-    File.mkdir_p!(outdir)
-
     js_files = Rewriter.rewrite_external_imports(js_files, ctx)
 
     bundle =
@@ -131,7 +184,11 @@ defmodule Volt.Builder.Output do
         sourcemap: Keyword.get(bundle_opts, :sourcemap, false),
         treeshake: Keyword.get(bundle_opts, :treeshake, false),
         define: Keyword.get(bundle_opts, :define, %{}),
-        external: Keyword.get(bundle_opts, :external, []),
+        external:
+          Enum.uniq(
+            Keyword.get(bundle_opts, :external, []) ++
+              Rewriter.preserved_external_imports(js_files, ctx)
+          ),
         module_types: Keyword.get(bundle_opts, :module_types, %{}),
         output: [
           entry_file_names: shared_entry_file_names(build_ctx.hash),
@@ -141,8 +198,7 @@ defmodule Volt.Builder.Output do
       )
 
     with {:ok, bundle_result} <- OXC.Bundle.run(bundle),
-         :ok <- write_shared_assets(bundle_result.outputs, outdir),
-         {:ok, css_results} <-
+         {:ok, css_results, css_artifacts} <-
            write_shared_css(
              css_parts,
              bundle_result.outputs,
@@ -151,7 +207,7 @@ defmodule Volt.Builder.Output do
              bundle_opts,
              asset_url_prefix
            ) do
-      js_results =
+      prepared_js =
         bundle_result.outputs
         |> Enum.filter(&(&1.type in [:entry, :chunk]))
         |> Enum.map(fn output ->
@@ -163,33 +219,60 @@ defmodule Volt.Builder.Output do
               type: output.type
             })
 
-          Writer.write_js(outdir, output.file_name, code, output.sourcemap,
-            hidden: sourcemap_hidden
-          )
+          artifacts =
+            Volt.Builder.Artifact.javascript(output.file_name, code, output.sourcemap,
+              hidden: sourcemap_hidden
+            )
 
-          %Volt.Builder.OutputFile{
-            path: Path.join(outdir, output.file_name),
-            size: byte_size(code),
-            chunk_id: output.file_name,
-            type: output.type
-          }
+          {%Volt.Builder.OutputFile{
+             path: Path.join(outdir, output.file_name),
+             size: byte_size(code),
+             chunk_id: output.file_name,
+             type: output.type
+           }, artifacts}
+        end)
+
+      js_results = Enum.map(prepared_js, &elem(&1, 0))
+
+      artifacts =
+        Enum.flat_map(prepared_js, &elem(&1, 1)) ++
+          List.flatten(css_artifacts) ++ shared_assets(bundle_result.outputs) ++ asset_artifacts
+
+      chunk_keys =
+        Map.new(Enum.filter(bundle_result.outputs, &(&1.type in [:entry, :chunk])), fn output ->
+          {output.file_name,
+           if(output.type == :entry, do: "#{output.name}.js", else: output.file_name)}
         end)
 
       manifest =
         bundle_result.outputs
         |> Enum.reduce(%{}, fn output, acc ->
+          output =
+            if output.type in [:entry, :chunk] do
+              %{
+                output
+                | imports: manifest_imports(output.imports, chunk_keys),
+                  dynamic_imports: manifest_imports(output.dynamic_imports, chunk_keys)
+              }
+            else
+              output
+            end
+
           output_manifest_entry(output, css_results, assets, acc)
         end)
         |> Writer.add_asset_entries(assets)
         |> Writer.add_asset_entries(css_assets(css_results))
 
-      {:ok,
-       %Volt.Builder.Result{
-         js: Enum.filter(js_results, &(&1.type == :entry)),
-         css: nil,
-         manifest: manifest,
-         chunks: js_results
-       }}
+      with {:ok, plan} <- Volt.Builder.Plan.new(artifacts) do
+        {:ok,
+         %Volt.Builder.Result{
+           js: Enum.filter(js_results, &(&1.type == :entry)),
+           css: nil,
+           styles: css_results |> Map.values() |> Enum.sort_by(& &1.path),
+           manifest: manifest,
+           chunks: js_results
+         }, plan}
+      end
     end
   end
 
@@ -209,7 +292,7 @@ defmodule Volt.Builder.Output do
   defp shared_asset_file_names(false), do: "[name][extname]"
 
   defp write_shared_css([], _outputs, _modules, _outdir, _bundle_opts, _asset_url_prefix),
-    do: {:ok, %{}}
+    do: {:ok, %{}, []}
 
   defp write_shared_css(css_parts, outputs, modules, outdir, bundle_opts, asset_url_prefix) do
     label_to_output = shared_label_to_output(outputs)
@@ -223,13 +306,18 @@ defmodule Volt.Builder.Output do
       css_parts
       |> Enum.group_by(fn {path, _css} -> Map.get(label_to_output, module_labels[path]) end)
       |> Enum.reject(fn {file_name, _parts} -> is_nil(file_name) end)
-      |> Enum.reduce_while({:ok, %{}}, fn {file_name, parts}, {:ok, acc} ->
+      |> Enum.reduce_while({:ok, %{}, []}, fn {file_name, parts}, {:ok, acc, artifacts} ->
         name = file_name |> Path.basename() |> Path.rootname()
 
-        case Writer.write_css(parts, outdir, name, false, css_opts) do
-          {:ok, nil} -> {:cont, {:ok, acc}}
-          {:ok, css_result} -> {:cont, {:ok, Map.put(acc, file_name, css_result)}}
-          {:error, _} = error -> {:halt, error}
+        case Writer.prepare_css(parts, outdir, name, false, css_opts) do
+          {:ok, nil, _plan} ->
+            {:cont, {:ok, acc, artifacts}}
+
+          {:ok, css_result, plan} ->
+            {:cont, {:ok, Map.put(acc, file_name, css_result), [plan.artifacts | artifacts]}}
+
+          {:error, _} = error ->
+            {:halt, error}
         end
       end)
     end
@@ -246,17 +334,22 @@ defmodule Volt.Builder.Output do
     |> Map.new()
   end
 
-  defp write_shared_assets(outputs, outdir) do
+  defp shared_assets(outputs) do
     outputs
     |> Enum.filter(&(&1.type == :asset))
     |> Enum.reject(&String.ends_with?(&1.file_name, ".map"))
-    |> Enum.each(fn output ->
-      path = Path.join(outdir, output.file_name)
-      File.mkdir_p!(Path.dirname(path))
-      File.write!(path, output.source || "")
+    |> Enum.map(fn output ->
+      %Volt.Builder.Artifact{file: output.file_name, content: output.source || ""}
     end)
+  end
 
-    :ok
+  defp manifest_imports(imports, chunk_keys) do
+    Enum.flat_map(imports, fn reference ->
+      case Map.fetch(chunk_keys, reference) do
+        {:ok, key} -> [key]
+        :error -> []
+      end
+    end)
   end
 
   defp output_manifest_entry(%{type: :asset} = output, _css_results, _assets, acc) do
@@ -289,7 +382,26 @@ defmodule Volt.Builder.Output do
   defp maybe_add_entry_assets(entry, _type, _assets), do: entry
 
   @doc "Bundle modules into separate chunks based on the chunk graph."
-  def build_chunks(entry, name, {js_files, css_parts, assets}, {modules, dep_map}, build_ctx) do
+  def build_chunks(entry, name, compiled, graph_input, build_ctx) do
+    with {:ok, result, plan} <- prepare_chunks(entry, name, compiled, graph_input, build_ctx),
+         :ok <- Writer.write_plan(build_ctx.outdir, plan) do
+      {:ok, result}
+    end
+  end
+
+  @doc "Prepare split chunks and their stylesheets without writing output."
+  def prepare_chunks(
+        entry,
+        name,
+        %Volt.Builder.Compiled{
+          scripts: js_files,
+          styles: css_parts,
+          assets: assets,
+          artifacts: asset_artifacts
+        },
+        {modules, dep_map},
+        build_ctx
+      ) do
     %{
       outdir: outdir,
       hash: hash,
@@ -300,8 +412,6 @@ defmodule Volt.Builder.Output do
       asset_url_prefix: asset_url_prefix
     } = build_ctx
 
-    File.mkdir_p!(outdir)
-
     graph = Volt.ChunkGraph.build(entry, modules, dep_map, manual_chunks: manual_chunks)
     js_map = Map.new(js_files)
     module_labels = Map.new(modules, fn {path, label, _source} -> {path, label} end)
@@ -318,7 +428,7 @@ defmodule Volt.Builder.Output do
            ) do
       css_opts = Keyword.put(bundle_opts, :asset_url_prefix, asset_url_prefix)
 
-      with {:ok, css_results} <-
+      with {:ok, css_results, css_artifacts} <-
              write_chunk_css(css_parts, graph, outdir, name, hash, css_opts) do
         {chunk_url_map, processed_chunks} =
           finalize_chunk_urls(
@@ -333,21 +443,30 @@ defmodule Volt.Builder.Output do
             dep_map
           )
 
-        js_results =
+        prepared_js =
           Enum.map(processed_chunks, fn {chunk_id, {code, sourcemap}} ->
             chunk = graph.chunks[chunk_id]
             filename = chunk_url_map[chunk_id]
 
-            Writer.write_js(outdir, filename, code, sourcemap, hidden: sourcemap_hidden)
-
-            %Volt.Builder.OutputFile{
-              path: Path.join(outdir, filename),
-              size: byte_size(code),
-              chunk_id: chunk_id,
-              type: chunk.type
-            }
+            artifacts =
+              Volt.Builder.Artifact.javascript(filename, code, sourcemap,
+                hidden: sourcemap_hidden
+              )
+
+            {%Volt.Builder.OutputFile{
+               path: Path.join(outdir, filename),
+               size: byte_size(code),
+               chunk_id: chunk_id,
+               type: chunk.type
+             }, artifacts}
           end)
 
+        js_results = Enum.map(prepared_js, &elem(&1, 0))
+
+        artifacts =
+          Enum.flat_map(prepared_js, &elem(&1, 1)) ++
+            List.flatten(css_artifacts) ++ asset_artifacts
+
         entry_js = Enum.find(js_results, &(&1.type == :entry)) || hd(js_results)
         entry_css = css_results[entry_js.chunk_id]
 
@@ -378,13 +497,16 @@ defmodule Volt.Builder.Output do
           |> Writer.add_asset_entries(assets)
           |> Writer.add_asset_entries(css_assets(css_results))
 
-        {:ok,
-         %Volt.Builder.Result{
-           js: entry_js,
-           css: entry_css,
-           manifest: manifest,
-           chunks: js_results
-         }}
+        with {:ok, plan} <- Volt.Builder.Plan.new(artifacts) do
+          {:ok,
+           %Volt.Builder.Result{
+             js: entry_js,
+             css: entry_css,
+             styles: css_results |> Map.values() |> Enum.sort_by(& &1.path),
+             manifest: manifest,
+             chunks: js_results
+           }, plan}
+        end
       end
     end
   end
@@ -434,7 +556,6 @@ defmodule Volt.Builder.Output do
       process_chunks(
         chunk_bundles,
         graph,
-        js_map,
         module_labels,
         css_results,
         ctx,
@@ -466,7 +587,6 @@ defmodule Volt.Builder.Output do
   defp process_chunks(
          chunk_bundles,
          graph,
-         js_map,
          module_labels,
          css_results,
          ctx,
@@ -477,9 +597,7 @@ defmodule Volt.Builder.Output do
 
     Map.new(chunk_bundles, fn {chunk_id, {code, sourcemap}} ->
       chunk = graph.chunks[chunk_id]
-      chunk_js = select_chunk_files(chunk.modules, js_map, module_labels)
       chunk_import_map = chunk_import_map(chunk, graph, module_labels, dep_map)
-      code = Rewriter.inject_external_preamble(code, chunk_js, ctx)
       code = Rewriter.rewrite_chunk_imports(code, chunk_import_map, chunk_url_map)
       code = Rewriter.rewrite_dynamic_preloads(code, preload_map)
 
@@ -536,13 +654,18 @@ defmodule Volt.Builder.Output do
   defp write_chunk_css(css_parts, graph, outdir, name, hash, css_opts) do
     css_parts
     |> Enum.group_by(fn {path, _css} -> Map.get(graph.module_to_chunk, path, "entry") end)
-    |> Enum.reduce_while({:ok, %{}}, fn {chunk_id, parts}, {:ok, acc} ->
+    |> Enum.reduce_while({:ok, %{}, []}, fn {chunk_id, parts}, {:ok, acc, artifacts} ->
       chunk = graph.chunks[chunk_id]
 
-      case Writer.write_css(parts, outdir, chunk_output_name(chunk, name), hash, css_opts) do
-        {:ok, nil} -> {:cont, {:ok, acc}}
-        {:ok, css_result} -> {:cont, {:ok, Map.put(acc, chunk_id, css_result)}}
-        {:error, _} = error -> {:halt, error}
+      case Writer.prepare_css(parts, outdir, chunk_output_name(chunk, name), hash, css_opts) do
+        {:ok, nil, _plan} ->
+          {:cont, {:ok, acc, artifacts}}
+
+        {:ok, css_result, plan} ->
+          {:cont, {:ok, Map.put(acc, chunk_id, css_result), [plan.artifacts | artifacts]}}
+
+        {:error, _} = error ->
+          {:halt, error}
       end
     end)
   end
@@ -678,6 +801,7 @@ defmodule Volt.Builder.Output do
           bundle_opts
           |> Keyword.put(:entry, chunk_entry_label(chunk_js))
           |> put_external_imports(external)
+          |> put_external_imports(Rewriter.preserved_external_imports(chunk_js, ctx))
 
         case bundle_js_files(chunk_js, bundle_opts) do
           {:ok, result} ->
diff --git a/lib/volt/builder/context/output.ex b/lib/volt/builder/output_context.ex
similarity index 86%
rename from lib/volt/builder/context/output.ex
rename to lib/volt/builder/output_context.ex
index 1cc6d7e..db285e4 100644
--- a/lib/volt/builder/context/output.ex
+++ b/lib/volt/builder/output_context.ex
@@ -4,6 +4,7 @@ defmodule Volt.Builder.OutputContext do
   defstruct plugins: [],
             external_set: MapSet.new(),
             external_globals: %{},
+            external_imports: MapSet.new(),
             workers: %{},
             worker_results: %{}
 end
diff --git a/lib/volt/builder/output/file.ex b/lib/volt/builder/output_file.ex
similarity index 50%
rename from lib/volt/builder/output/file.ex
rename to lib/volt/builder/output_file.ex
index ee00a3c..51987c6 100644
--- a/lib/volt/builder/output/file.ex
+++ b/lib/volt/builder/output_file.ex
@@ -6,4 +6,12 @@ defmodule Volt.Builder.OutputFile do
             assets: [],
             chunk_id: nil,
             type: nil
+
+  @type t :: %__MODULE__{
+          path: String.t(),
+          size: non_neg_integer(),
+          assets: [Volt.Builder.Asset.t()],
+          chunk_id: String.t() | nil,
+          type: :entry | :chunk | nil
+        }
 end
diff --git a/lib/volt/builder/plan.ex b/lib/volt/builder/plan.ex
new file mode 100644
index 0000000..bdda980
--- /dev/null
+++ b/lib/volt/builder/plan.ex
@@ -0,0 +1,69 @@
+defmodule Volt.Builder.Plan do
+  @moduledoc false
+
+  alias Volt.Builder.Artifact
+
+  @enforce_keys [:artifacts]
+  defstruct [:artifacts]
+
+  @type t :: %__MODULE__{artifacts: [Artifact.t()]}
+
+  @spec new([Artifact.t()]) :: {:ok, t()} | {:error, term()}
+  def new(artifacts) do
+    artifacts
+    |> Enum.reduce_while({:ok, %{}}, fn %Artifact{} = artifact, {:ok, files} ->
+      cond do
+        not safe_path?(artifact.file) ->
+          {:halt, {:error, {:invalid_output_path, artifact.file}}}
+
+        Map.has_key?(files, artifact.file) and files[artifact.file] != artifact ->
+          {:halt, {:error, {:output_collision, artifact.file}}}
+
+        true ->
+          {:cont, {:ok, Map.put(files, artifact.file, artifact)}}
+      end
+    end)
+    |> case do
+      {:ok, files} -> {:ok, %__MODULE__{artifacts: Enum.sort_by(Map.values(files), & &1.file)}}
+      {:error, _} = error -> error
+    end
+  end
+
+  @doc "Validate manifest identities and emitted file references against a prepared plan."
+  def validate_manifest(%__MODULE__{artifacts: artifacts}, manifest) do
+    files = MapSet.new(artifacts, & &1.file)
+
+    errors =
+      Enum.flat_map(manifest, fn {key, %Volt.Builder.ManifestEntry{} = entry} ->
+        missing_keys =
+          for reference <- entry.imports ++ entry.dynamicImports,
+              not Map.has_key?(manifest, reference),
+              do: {:missing_manifest_entry, key, reference}
+
+        missing_files =
+          for file <- [entry.file | entry.css ++ entry.assets],
+              not MapSet.member?(files, file),
+              do: {:missing_artifact, key, file}
+
+        missing_keys ++ missing_files
+      end)
+      |> Enum.uniq()
+      |> Enum.sort()
+
+    case errors do
+      [] -> :ok
+      errors -> {:error, {:invalid_manifest, errors}}
+    end
+  end
+
+  defp safe_path?(path) when is_binary(path) do
+    parts = Path.split(path)
+
+    path != "" and Path.type(path) == :relative and
+      not String.contains?(path, ["\\", ":", <<0>>]) and
+      Enum.all?(parts, &(&1 not in [".", ".."])) and
+      Path.join(parts) == path
+  end
+
+  defp safe_path?(_path), do: false
+end
diff --git a/lib/volt/builder/publication.ex b/lib/volt/builder/publication.ex
new file mode 100644
index 0000000..7b00012
--- /dev/null
+++ b/lib/volt/builder/publication.ex
@@ -0,0 +1,98 @@
+defmodule Volt.Builder.Publication do
+  @moduledoc "Staged asset publication with manifest-last installation, not a whole-directory transaction."
+
+  alias Volt.Builder.Plan
+
+  @spec write(String.t(), Plan.t()) :: :ok | {:error, term()}
+  def write(outdir, %Plan{} = plan) do
+    root = Path.expand(outdir)
+    lock = {{__MODULE__, root}, self()}
+    :global.trans(lock, fn -> publish(root, plan) end, [node()])
+  end
+
+  defp publish(root, plan) do
+    with :ok <- validate_destinations(root, plan.artifacts),
+         :ok <- File.mkdir_p(Path.dirname(root)),
+         {:ok, stage} <- create_stage(root, 10) do
+      try do
+        with :ok <- stage_files(stage, plan.artifacts),
+             :ok <- validate_destinations(root, plan.artifacts) do
+          install(root, stage, plan.artifacts)
+        end
+      after
+        File.rm_rf(stage)
+      end
+    end
+  end
+
+  defp create_stage(_root, 0), do: {:error, :staging_name_exhausted}
+
+  defp create_stage(root, attempts) do
+    stage =
+      root <> ".volt-stage-" <> Base.url_encode64(:crypto.strong_rand_bytes(12), padding: false)
+
+    case File.mkdir(stage) do
+      :ok -> {:ok, stage}
+      {:error, :eexist} -> create_stage(root, attempts - 1)
+      {:error, reason} -> {:error, {:staging_directory_failed, reason}}
+    end
+  end
+
+  defp validate_destinations(root, artifacts) do
+    paths =
+      Enum.flat_map(artifacts, fn artifact ->
+        {_path, paths} =
+          Enum.reduce(Path.split(artifact.file), {root, [root]}, fn part, {parent, paths} ->
+            path = Path.join(parent, part)
+            {path, [path | paths]}
+          end)
+
+        paths
+      end)
+
+    paths
+    |> Enum.uniq()
+    |> Enum.reduce_while(:ok, fn path, :ok ->
+      case File.lstat(path) do
+        {:ok, %{type: :symlink}} -> {:halt, {:error, {:symlink_destination, path}}}
+        {:ok, _} -> {:cont, :ok}
+        {:error, reason} when reason in [:enoent, :enotdir] -> {:cont, :ok}
+        {:error, reason} -> {:halt, {:error, {:destination_check_failed, path, reason}}}
+      end
+    end)
+  end
+
+  defp stage_files(stage, artifacts) do
+    Enum.reduce_while(artifacts, :ok, fn artifact, :ok ->
+      path = Path.join(stage, artifact.file)
+
+      case write_file(path, artifact.content) do
+        :ok -> {:cont, :ok}
+        {:error, reason} -> {:halt, {:error, {:staging_failed, artifact.file, reason}}}
+      end
+    end)
+  end
+
+  defp write_file(path, content) do
+    with :ok <- File.mkdir_p(Path.dirname(path)), do: File.write(path, content)
+  end
+
+  defp install(root, stage, artifacts) do
+    artifacts
+    |> Enum.sort_by(fn artifact ->
+      {Path.basename(artifact.file) == "manifest.json", artifact.file}
+    end)
+    |> Enum.reduce_while(:ok, fn artifact, :ok ->
+      destination = Path.join(root, artifact.file)
+
+      result =
+        with :ok <- File.mkdir_p(Path.dirname(destination)),
+             do: File.rename(Path.join(stage, artifact.file), destination)
+
+      case result do
+        :ok -> {:cont, :ok}
+        {:error, reason} -> {:halt, {:error, {:publication_failed, artifact.file, reason}}}
+      end
+    end)
+  end
+end
diff --git a/lib/volt/builder/resolver.ex b/lib/volt/builder/resolver.ex
index 18c734b..dc22658 100644
--- a/lib/volt/builder/resolver.ex
+++ b/lib/volt/builder/resolver.ex
@@ -6,17 +6,63 @@ defmodule Volt.Builder.Resolver do
 
   Returns `{:ok, path}`, `:skip` (for externals/node builtins), or `{:error, reason}`.
   """
+  # A module with nothing in it, for imports a package's `browser` field maps
+  # to `false`. The collector supplies its source; see `empty_module?/1`.
+  @empty_module "volt:empty.js"
+
   def resolve(specifier, importer, ctx) do
     {path_specifier, query} = Volt.JS.Specifier.split_query(specifier)
 
-    if external?(path_specifier, ctx.external) do
-      :skip
+    if external?(path_specifier, ctx.external),
+      do: :skip,
+      else: resolve_for_browser(path_specifier, importer, ctx, query)
+  end
+
+  @doc "Return whether a resolved path is the empty module."
+  def empty_module?(path), do: path == @empty_module
+
+  # A package's `browser` field says what a specifier means in browsers: `false`
+  # for nothing, as for Node built-ins a package only uses when it has them, or a
+  # path to a replacement. esbuild, webpack and Rollup honour it the same way.
+  defp resolve_for_browser(specifier, importer, ctx, query) do
+    case browser_field(specifier, importer) do
+      false -> {:ok, @empty_module}
+      {:replace, path} -> append_query(resolve_relative(path, importer, ctx), query)
+      nil -> do_resolve(specifier, importer, ctx, query)
+    end
+  end
+
+  defp browser_field(_specifier, nil), do: nil
+
+  defp browser_field(specifier, importer) do
+    with {:ok, package_dir, %{"browser" => browser}} when is_map(browser) <-
+           NPM.Resolution.PackageResolver.nearest_package(Path.dirname(importer_path(importer))),
+         {:ok, value} <- fetch_browser_mapping(browser, specifier) do
+      case value do
+        false -> false
+        path when is_binary(path) -> {:replace, Path.expand(path, package_dir)}
+        _other -> nil
+      end
     else
-      do_resolve(path_specifier, importer, ctx, query)
+      _none -> nil
     end
   end
 
-  def absolute?(specifier), do: String.starts_with?(specifier, "/")
+  defp fetch_browser_mapping(browser, specifier) do
+    Enum.find_value([specifier, "node:" <> specifier], :error, fn key ->
+      case Map.fetch(browser, key) do
+        {:ok, value} -> {:ok, value}
+        :error -> nil
+      end
+    end)
+  end
+
+  defp importer_path(importer) do
+    {path, _query} = Volt.URL.split_query(importer)
+    path
+  end
+
+  def absolute?(specifier), do: Path.type(specifier) == :absolute
 
   defp do_resolve(specifier, importer, ctx, query) do
     case Volt.PluginRunner.resolve(ctx.plugins, specifier, importer) do
@@ -46,7 +92,12 @@ defmodule Volt.Builder.Resolver do
 
   defp resolve_by_type(specifier, importer, ctx) do
     cond do
-      NPM.Resolution.PackageResolver.node_builtin?(specifier) ->
+      Volt.JS.Specifier.node_builtin?(specifier) ->
+        :skip
+
+      # OXC's transform imports helpers from `@oxc-project/runtime`, and `OXC.bundle/2`
+      # provides them itself, so they never come from `node_modules`.
+      Volt.JS.Specifier.oxc_runtime_helper?(specifier) ->
         :skip
 
       absolute?(specifier) ->
@@ -59,7 +110,7 @@ defmodule Volt.Builder.Resolver do
         resolve_relative(specifier, importer, ctx)
 
       true ->
-        resolve_bare(specifier, ctx.node_modules, ctx.resolve_dirs, ctx.plugins)
+        resolve_bare(specifier, importer, ctx)
     end
   end
 
@@ -129,23 +180,81 @@ defmodule Volt.Builder.Resolver do
       Enum.any?(external, &String.starts_with?(specifier, &1 <> "/"))
   end
 
-  defp resolve_bare(specifier, node_modules, resolve_dirs, plugins) do
-    dirs = if node_modules, do: [node_modules | resolve_dirs], else: resolve_dirs
+  defp scoped_package_dirs(nil, _scopes), do: []
+
+  defp scoped_package_dirs(importer, scopes) do
+    {importer_path, _query} = Volt.URL.split_query(importer)
+    importer_path = Path.expand(importer_path)
+
+    for {source_root, package_dir} <- scopes,
+        path_within?(importer_path, source_root) or path_within?(importer_path, package_dir),
+        do: package_dir
+  end
+
+  defp path_within?(path, root) do
+    relative = Path.relative_to(path, root)
+    Path.type(relative) == :relative and not match?([".." | _rest], Path.split(relative))
+  end
+
+  defp resolve_bare(specifier, importer, ctx) do
+    global_dirs =
+      if ctx.node_modules, do: [ctx.node_modules | ctx.resolve_dirs], else: ctx.resolve_dirs
+
+    ancestors = ancestor_node_modules(importer)
+    configured = scoped_package_dirs(importer, ctx.package_scopes) ++ global_dirs
+
+    # A package resolves its own dependencies Node's way, so nested versions win.
+    # Application sources keep the configured scopes and directories first, such as
+    # the framework runtimes Volt installs, and fall back to the directories above.
+    dirs =
+      if inside_node_modules?(importer),
+        do: Enum.uniq(ancestors ++ configured),
+        else: Enum.uniq(configured ++ ancestors)
 
     case Enum.find_value(dirs, fn dir ->
            {package_name, _subpath} = NPM.Resolution.PackageResolver.split_specifier(specifier)
            package_dir = Path.join(dir, package_name)
 
            if File.dir?(package_dir) do
-             resolve_in_package(specifier, dir, package_dir, plugins) || :unresolved_package
+             resolve_in_package(specifier, dir, package_dir, ctx.plugins) || :unresolved_package
            end
          end) do
-      nil -> :skip
+      nil -> {:error, {:not_found, specifier}}
       :unresolved_package -> {:error, {:not_found, specifier}}
       result -> result
     end
   end
 
+  @doc "Return whether a module path, with or without a query, lies in a `node_modules` directory."
+  @spec inside_node_modules?(String.t() | nil) :: boolean()
+  def inside_node_modules?(nil), do: false
+
+  def inside_node_modules?(importer) do
+    {importer_path, _query} = Volt.URL.split_query(importer)
+    "node_modules" in Path.split(Path.expand(importer_path))
+  end
+
+  # The `node_modules` directories Node searches, nearest first: `D/node_modules` for
+  # each directory `D` above the importer that is not itself a `node_modules`. That
+  # finds dependencies nested under their dependent, as npm installs conflicting
+  # versions, pnpm's sibling layout, and packages vendored beside `priv` sources.
+  defp ancestor_node_modules(nil), do: []
+
+  defp ancestor_node_modules(importer) do
+    {importer_path, _query} = Volt.URL.split_query(importer)
+
+    importer_path
+    |> Path.expand()
+    |> Path.dirname()
+    |> Stream.unfold(fn
+      nil -> nil
+      dir -> {dir, if(Path.dirname(dir) == dir, do: nil, else: Path.dirname(dir))}
+    end)
+    |> Stream.reject(&(Path.basename(&1) == "node_modules"))
+    |> Stream.map(&Path.join(&1, "node_modules"))
+    |> Enum.filter(&File.dir?/1)
+  end
+
   defp resolve_in_package(specifier, dir, package_dir, plugins) do
     subpath = Volt.JS.Package.subpath_for(specifier)
     extensions = Volt.JS.Extensions.resolvable(plugins)
diff --git a/lib/volt/builder/result.ex b/lib/volt/builder/result.ex
index 8463817..129ca63 100644
--- a/lib/volt/builder/result.ex
+++ b/lib/volt/builder/result.ex
@@ -1,7 +1,16 @@
 defmodule Volt.Builder.Result do
   @moduledoc "Production build result returned from `Volt.Builder`."
 
-  defstruct js: [], css: nil, manifest: %{}, chunks: []
+  defstruct js: [], css: nil, styles: [], manifest: %{}, chunks: [], declarations: []
+
+  @type t :: %__MODULE__{
+          js: Volt.Builder.OutputFile.t() | [Volt.Builder.OutputFile.t()],
+          css: Volt.Builder.OutputFile.t() | nil,
+          styles: [Volt.Builder.OutputFile.t()],
+          manifest: %{String.t() => Volt.Builder.ManifestEntry.t()},
+          chunks: [Volt.Builder.OutputFile.t()],
+          declarations: [Volt.Builder.OutputFile.t()]
+        }
 
   @behaviour Access
 
diff --git a/lib/volt/builder/rewriter.ex b/lib/volt/builder/rewriter.ex
index d48f6fa..8379021 100644
--- a/lib/volt/builder/rewriter.ex
+++ b/lib/volt/builder/rewriter.ex
@@ -14,6 +14,28 @@ defmodule Volt.Builder.Rewriter do
     end
   end
 
+  @doc "Specifiers imported by `js_files` that stay as imports in the bundle output."
+  def preserved_external_imports(js_files, ctx) do
+    if MapSet.size(ctx.external_imports) == 0 do
+      []
+    else
+      js_files
+      |> Enum.flat_map(fn {_label, code} ->
+        case OXC.select(code, "module.js", :import_specifiers) do
+          {:ok, specifiers} -> specifiers
+          {:error, _} -> []
+        end
+      end)
+      |> Enum.uniq()
+      |> Enum.filter(&preserved_external?(&1, ctx.external_imports))
+    end
+  end
+
+  defp preserved_external?(specifier, externals) do
+    MapSet.member?(externals, specifier) or
+      Enum.any?(externals, &String.starts_with?(specifier, &1 <> "/"))
+  end
+
   def external_chunk_imports(js_files, chunk_import_map) do
     js_files
     |> Enum.flat_map(fn {_label, code} ->
@@ -146,15 +168,7 @@ defmodule Volt.Builder.Rewriter do
     patches
   end
 
-  defp preload_helper do
-    {:volt, "ts"}
-    |> Volt.Priv.path("client/preload-global.ts")
-    |> Volt.JS.Runtime.Bundler.bundle_file()
-    |> case do
-      {:ok, code} -> code <> "\n"
-      {:error, reason} -> raise "could not bundle Volt preload helper: #{inspect(reason)}"
-    end
-  end
+  defp preload_helper, do: Volt.Priv.bundle!({:volt, "ts"}, "client/preload-global.ts") <> "\n"
 
   defp worker_filename_map(worker_specs, ctx) do
     worker_specs
diff --git a/lib/volt/builder/writer.ex b/lib/volt/builder/writer.ex
index ee49d92..e58ec5d 100644
--- a/lib/volt/builder/writer.ex
+++ b/lib/volt/builder/writer.ex
@@ -2,59 +2,79 @@ defmodule Volt.Builder.Writer do
   @moduledoc "Writes production JavaScript, CSS, assets, sourcemaps, and manifests."
 
   def write_js(outdir, filename, code, sourcemap, opts \\ []) do
-    hidden = Keyword.get(opts, :hidden, false)
+    artifacts = Volt.Builder.Artifact.javascript(filename, code, sourcemap, opts)
 
-    code =
-      if sourcemap && !hidden do
-        code <> "\n//# sourceMappingURL=#{filename}.map\n"
-      else
-        code
-      end
+    {:ok, plan} = Volt.Builder.Plan.new(artifacts)
+    write_plan(outdir, plan)
+  end
 
-    File.write!(Path.join(outdir, filename), code)
+  @doc false
+  @spec write_plan(String.t(), Volt.Builder.Plan.t()) :: :ok | {:error, term()}
+  def write_plan(outdir, %Volt.Builder.Plan{} = plan) do
+    Volt.Builder.Publication.write(outdir, plan)
+  end
 
-    if sourcemap do
-      File.write!(Path.join(outdir, "#{filename}.map"), sourcemap)
+  def write_css(css_parts, outdir, name, hash, bundle_opts) do
+    with {:ok, result, plan} <- prepare_css(css_parts, outdir, name, hash, bundle_opts),
+         :ok <- write_plan(outdir, plan) do
+      {:ok, result}
     end
   end
 
-  def write_css([], _outdir, _name, _hash, _bundle_opts), do: {:ok, nil}
-
-  def write_css(css_parts, outdir, name, hash, bundle_opts) do
-    with {:ok, %{code: css_code, assets: assets}} <-
-           Volt.Builder.CSS.rewrite_parts(css_parts, outdir, bundle_opts),
-         {:ok, css_code} <- Volt.Builder.CSS.compile(css_code, bundle_opts) do
-      css_filename = hashed_name(name, css_code, ".css", hash)
-      css_path = Path.join(outdir, css_filename)
-      File.write!(css_path, css_code)
-      {:ok, %Volt.Builder.OutputFile{path: css_path, size: byte_size(css_code), assets: assets}}
+  def prepare_css([], _outdir, _name, _hash, _bundle_opts),
+    do: {:ok, nil, %Volt.Builder.Plan{artifacts: []}}
+
+  def prepare_css(css_parts, outdir, name, hash, bundle_opts) do
+    with {:ok, prepared} <- Volt.Builder.CSS.prepare_parts(css_parts, bundle_opts),
+         {:ok, css_code} <- Volt.Builder.CSS.compile(prepared.code, bundle_opts),
+         css_filename = hashed_name(name, css_code, ".css", hash),
+         {:ok, plan} <-
+           Volt.Builder.Plan.new([
+             %Volt.Builder.Artifact{file: css_filename, content: css_code} | prepared.artifacts
+           ]) do
+      {:ok,
+       %Volt.Builder.OutputFile{
+         path: Path.join(outdir, css_filename),
+         size: byte_size(css_code),
+         assets: prepared.assets
+       }, plan}
     end
   end
 
   def build_style_entry(name, css_code, outdir, hash, source_path \\ nil, bundle_opts \\ []) do
-    File.mkdir_p!(outdir)
+    with {:ok, result, plan} <-
+           prepare_style_entry(name, css_code, outdir, hash, source_path, bundle_opts),
+         :ok <- write_plan(outdir, plan) do
+      {:ok, result}
+    end
+  end
 
-    with {:ok, %{code: css_code, assets: assets}} <-
-           Volt.Builder.CSS.rewrite_part({source_path, css_code}, outdir, bundle_opts),
-         {:ok, css_code} <- Volt.Builder.CSS.compile(css_code, bundle_opts) do
-      css_filename = hashed_name(name, css_code, ".css", hash)
+  @doc "Prepare a standalone stylesheet and its referenced assets without writing files."
+  def prepare_style_entry(name, css_code, outdir, hash, source_path, bundle_opts) do
+    with {:ok, prepared} <-
+           Volt.Builder.CSS.prepare_part({source_path, css_code}, bundle_opts),
+         {:ok, css_code} <- Volt.Builder.CSS.compile(prepared.code, bundle_opts),
+         css_filename = hashed_name(name, css_code, ".css", hash),
+         {:ok, plan} <-
+           Volt.Builder.Plan.new([
+             %Volt.Builder.Artifact{file: css_filename, content: css_code} | prepared.artifacts
+           ]) do
       css_path = Path.join(outdir, css_filename)
 
       css_result = %Volt.Builder.OutputFile{
         path: css_path,
         size: byte_size(css_code),
-        assets: assets
+        assets: prepared.assets
       }
 
-      File.write!(css_path, css_code)
-
       manifest =
         %{
-          "#{name}.css" => %{
-            "file" => css_filename,
-            "src" => "#{name}.css",
-            "assets" => css_assets(css_filename, css_result)
-          }
+          "#{name}.css" =>
+            Volt.Builder.ManifestEntry.css(
+              "#{name}.css",
+              css_filename,
+              css_assets(css_filename, css_result)
+            )
         }
         |> add_asset_entries(css_result.assets)
 
@@ -62,8 +82,9 @@ defmodule Volt.Builder.Writer do
        %Volt.Builder.Result{
          js: [],
          css: css_result,
+         styles: [css_result],
          manifest: manifest
-       }}
+       }, plan}
     end
   end
 
@@ -106,7 +127,7 @@ defmodule Volt.Builder.Writer do
   end
 
   def hashed_name(name, content, ext, true) do
-    "#{name}-#{Volt.Format.content_hash(content)}#{ext}"
+    "#{name}-#{Volt.Builder.Naming.hash(content)}#{ext}"
   end
 
   def hashed_name(name, _content, ext, false), do: "#{name}#{ext}"
@@ -118,8 +139,7 @@ defmodule Volt.Builder.Writer do
   def asset_files(assets) do
     assets
     |> Enum.map(fn
-      %{file: file} -> file
-      %{"file" => file} -> file
+      %Volt.Builder.Asset{file: file} -> file
       file when is_binary(file) -> file
     end)
     |> Enum.uniq()
@@ -127,10 +147,7 @@ defmodule Volt.Builder.Writer do
 
   def add_asset_entries(manifest, assets) do
     Enum.reduce(assets, manifest, fn
-      %{src: src, file: file}, acc ->
-        Map.put_new(acc, src, Volt.Builder.ManifestEntry.asset(src, file))
-
-      %{"src" => src, "file" => file}, acc ->
+      %Volt.Builder.Asset{src: src, file: file}, acc ->
         Map.put_new(acc, src, Volt.Builder.ManifestEntry.asset(src, file))
 
       _file, acc ->
diff --git a/lib/volt/cache.ex b/lib/volt/cache.ex
index 13e702d..6111ef7 100644
--- a/lib/volt/cache.ex
+++ b/lib/volt/cache.ex
@@ -12,6 +12,9 @@ defmodule Volt.Cache do
 
   @type cache_entry :: %{mtime: integer(), entry: entry()}
 
+  defp location(%Volt.Dev.Session.Tables{cache: table}, path), do: {table, path}
+  defp location(session, path), do: {@table, {session, path}}
+
   @doc "Create the cache ETS table. Called once from Application.start/2."
   @spec create_table :: :ok
   def create_table do
@@ -21,44 +24,53 @@ defmodule Volt.Cache do
 
   @doc "Look up a cached entry. Returns `nil` on miss."
   @spec get(String.t(), integer()) :: entry() | nil
-  def get(path, mtime) do
-    case :ets.lookup(@table, path) do
-      [{^path, %{mtime: ^mtime, entry: entry}}] -> entry
+  def get(path, mtime, session \\ :default) do
+    {table, key} = location(session, path)
+
+    case :ets.lookup(table, key) do
+      [{^key, %{mtime: ^mtime, entry: entry}}] -> entry
       _ -> nil
     end
   end
 
   @doc "Look up any cached entry for a file path regardless of mtime."
   @spec get_file(String.t()) :: entry() | nil
-  def get_file(path) do
-    case :ets.lookup(@table, path) do
-      [{^path, %{entry: entry}}] -> entry
+  def get_file(path, session \\ :default) do
+    {table, key} = location(session, path)
+
+    case :ets.lookup(table, key) do
+      [{^key, %{entry: entry}}] -> entry
       [] -> nil
     end
   end
 
   @doc "Store a compiled entry."
   @spec put(String.t(), integer(), entry()) :: :ok
-  def put(path, mtime, entry) do
-    :ets.insert(@table, {path, %{mtime: mtime, entry: entry}})
+  def put(path, mtime, entry, session \\ :default) do
+    {table, key} = location(session, path)
+    :ets.insert(table, {key, %{mtime: mtime, entry: entry}})
     :ok
   end
 
   @doc "Evict the entry for a cache key."
   @spec evict(String.t()) :: :ok
-  def evict(key) do
-    :ets.delete(@table, key)
+  def evict(key, session \\ :default) do
+    {table, key} = location(session, key)
+    :ets.delete(table, key)
     :ok
   end
 
   @doc "Evict all cache entries derived from a file path, including variant keys like `path <> \"?import\"`."
   @spec evict_file(String.t()) :: :ok
-  def evict_file(path) do
-    evict(path)
-    evict(Volt.URL.append_query(path, "import"))
+  def evict_file(path, session \\ :default) do
+    evict(path, session)
+    evict(Volt.URL.append_query(path, "import"), session)
     :ok
   end
 
+  @doc "Clear entries belonging to one development session."
+  def clear_session(session), do: Volt.ETS.clear_session(@table, session)
+
   @doc "Clear all cached entries."
   @spec clear :: :ok
   def clear do
diff --git a/lib/volt/config.ex b/lib/volt/config.ex
index 97a70d3..c63efa3 100644
--- a/lib/volt/config.ex
+++ b/lib/volt/config.ex
@@ -130,20 +130,18 @@ defmodule Volt.Config do
 
   @spec build(atom() | nil, keyword()) :: map()
   def build(profile, overrides) do
-    flat_env =
-      Application.get_all_env(:volt)
-      |> Keyword.take(@build_keys)
-      |> Keyword.reject(fn {k, v} -> k == :format and not is_atom(v) end)
+    flat_env = Application.get_all_env(:volt) |> Keyword.take(@build_keys)
 
     profile_env =
       if profile do
-        Application.get_env(:volt, profile, [])
-        |> Keyword.take(@build_keys)
-        |> Keyword.reject(fn {k, v} -> k == :format and not is_atom(v) end)
+        Application.get_env(:volt, profile, []) |> Keyword.take(@build_keys)
       else
         []
       end
 
+    reject_formatter_options!(flat_env[:format])
+    reject_formatter_options!(profile_env[:format])
+
     config =
       @defaults
       |> Map.from_struct()
@@ -156,6 +154,23 @@ defmodule Volt.Config do
     %{config | aliases: Map.merge(tsconfig_paths, config.aliases)}
   end
 
+  @doc false
+  def reject_formatter_options!(format) when is_list(format) do
+    raise ArgumentError, """
+    formatter options are no longer read from `config :volt, :format`, which now \
+    only holds the build output format (`:iife`, `:esm`, or `:cjs`).
+
+    Move them to the `:volt` key of .formatter.exs:
+
+        [
+          plugins: [Volt.Formatter],
+          volt: #{inspect(format)}
+        ]
+    """
+  end
+
+  def reject_formatter_options!(_format), do: :ok
+
   @doc """
   Read dev server config, merged with defaults.
 
diff --git a/lib/volt/config/build.ex b/lib/volt/config/build.ex
index 1bbf77a..5bb388f 100644
--- a/lib/volt/config/build.ex
+++ b/lib/volt/config/build.ex
@@ -3,13 +3,16 @@ defmodule Volt.Config.Build do
 
   defstruct entry: Volt.Paths.entry(),
             outdir: Volt.Paths.static(),
+            output_layout: :split,
             public_dir: false,
+            assets_dir: "",
             target: :es2020,
             minify: true,
             sourcemap: true,
             hash: true,
             code_splitting: true,
             tree_shaking: true,
+            declarations: false,
             format: :iife,
             mode: :production,
             env_prefix: "VOLT_",
diff --git a/lib/volt/config/server.ex b/lib/volt/config/server.ex
index f11402c..7e7db3a 100644
--- a/lib/volt/config/server.ex
+++ b/lib/volt/config/server.ex
@@ -4,6 +4,8 @@ defmodule Volt.Config.Server do
   defstruct prefix: Volt.Paths.prefix(),
             watch_dirs: [],
             reload_dirs: [],
+            watch_ignored: [],
             hmr_timeout: 60_000,
+            morph: false,
             watch: true
 end
diff --git a/lib/volt/config/tailwind.ex b/lib/volt/config/tailwind.ex
new file mode 100644
index 0000000..2fe3d7a
--- /dev/null
+++ b/lib/volt/config/tailwind.ex
@@ -0,0 +1,42 @@
+defmodule Volt.Config.Tailwind do
+  @moduledoc "Normalized Tailwind CSS root configuration."
+
+  @enforce_keys [:name, :sources]
+  defstruct [:css, :name, :sources, :dev_url]
+
+  @type source :: %{
+          required(:base) => String.t(),
+          required(:pattern) => String.t(),
+          optional(:negated) => boolean()
+        }
+  @type t :: %__MODULE__{
+          css: String.t() | nil,
+          name: String.t(),
+          sources: [source()],
+          dev_url: String.t()
+        }
+
+  @spec enabled?(keyword() | boolean() | nil) :: boolean()
+  def enabled?(true), do: true
+  def enabled?(config), do: is_list(config) and config != []
+
+  @spec new(keyword() | boolean() | nil, keyword()) :: t()
+  def new(config, overrides \\ [])
+  def new(config, overrides) when config in [nil, false, true], do: new([], overrides)
+
+  def new(config, overrides) when is_list(config) do
+    css = overrides[:css] || config[:css]
+    name = overrides[:name] || config[:name] || entry_name(css)
+
+    %__MODULE__{
+      css: if(css, do: Volt.Paths.expand(css)),
+      name: name,
+      sources: overrides[:sources] || config[:sources] || [],
+      dev_url: overrides[:dev_url] || config[:dev_url] || default_dev_url(name)
+    }
+  end
+
+  defp entry_name(nil), do: "app"
+  defp entry_name(css), do: css |> Path.basename() |> Path.rootname()
+  defp default_dev_url(name), do: "/assets/css/#{name}.css"
+end
diff --git a/lib/volt/css/asset_url_rewriter.ex b/lib/volt/css/asset_url_rewriter.ex
index a18d448..0e5643c 100644
--- a/lib/volt/css/asset_url_rewriter.ex
+++ b/lib/volt/css/asset_url_rewriter.ex
@@ -8,7 +8,7 @@ defmodule Volt.CSS.AssetURLRewriter do
 
   @type rewrite_result :: {:ok, String.t()} | {:error, term()}
   @type rewrite_assets_result ::
-          {:ok, %{code: String.t(), assets: [String.t() | map()]}} | {:error, term()}
+          {:ok, %{code: String.t(), assets: [Volt.Builder.Asset.t()]}} | {:error, term()}
 
   @doc "Rewrite relative CSS asset URLs to hashed output URLs."
   @spec rewrite(String.t(), String.t() | nil, String.t(), keyword()) :: rewrite_result()
@@ -26,26 +26,62 @@ defmodule Volt.CSS.AssetURLRewriter do
   def rewrite_with_assets(css, nil, _outdir, _opts), do: {:ok, %{code: css, assets: []}}
 
   def rewrite_with_assets(css, source_path, outdir, opts) do
+    with {:ok, result} <- prepare(css, source_path, opts) do
+      Volt.Assets.write_artifacts(result.artifacts, outdir)
+
+      {:ok, %{code: result.code, assets: result.assets}}
+    end
+  end
+
+  @doc false
+  def prepare(css, source_path, opts \\ [])
+
+  def prepare(css, nil, _opts),
+    do: {:ok, %Volt.Builder.CSS.Prepared{code: css, assets: [], artifacts: []}}
+
+  def prepare(css, source_path, opts) do
     prefix = Keyword.get(opts, :prefix, Volt.Paths.prefix())
 
-    with {:ok, code, {assets, _emitted}} <-
+    with {:ok, code, {assets, emitted}} <-
            rewrite_urls(css, [filename: source_path], {[], %{}}, fn url, state ->
-             rewrite_build_url(url, state, source_path, outdir, prefix, opts)
+             rewrite_build_url(url, state, source_path, prefix, opts)
            end) do
-      {:ok, %{code: code, assets: Enum.reverse(assets)}}
+      artifacts =
+        emitted
+        |> Enum.map(fn {_path, {_file, _asset, artifact}} -> artifact end)
+        |> Enum.sort_by(& &1.file)
+
+      {:ok,
+       %Volt.Builder.CSS.Prepared{code: code, assets: Enum.reverse(assets), artifacts: artifacts}}
     else
       {:error, reason} -> {:error, {:css_parse_failed, reason}}
     end
   end
 
+  @doc "Rebase relative asset URLs before an imported stylesheet loses its source location."
+  def rebase(css, source_path, output_base) do
+    Vize.CSS.rewrite_urls(css, [filename: source_path], fn url ->
+      uri = URI.parse(url)
+
+      if rewrite_candidate?(url) and Volt.Assets.asset?(uri.path) do
+        absolute = Path.expand(uri.path, Path.dirname(source_path))
+        relative = Path.relative_to(absolute, output_base, force: true)
+        {:rewrite, append_suffix(relative, uri)}
+      else
+        :keep
+      end
+    end)
+  end
+
   @doc "Rewrite relative CSS asset URLs to dev-server URLs without copying files."
   @spec rewrite_dev(String.t(), String.t() | nil, String.t(), String.t()) :: rewrite_result()
-  def rewrite_dev(css, nil, _root, _prefix), do: {:ok, css}
+  def rewrite_dev(css, source_path, root, prefix, opts \\ [])
+  def rewrite_dev(css, nil, _root, _prefix, _opts), do: {:ok, css}
 
-  def rewrite_dev(css, source_path, root, prefix) do
+  def rewrite_dev(css, source_path, root, prefix, opts) do
     with {:ok, css} <-
            Vize.CSS.rewrite_urls(css, [filename: source_path], fn url ->
-             case dev_url(url, source_path, root, prefix) do
+             case dev_url(url, source_path, root, prefix, opts) do
                {:ok, ^url} -> :keep
                {:ok, rewritten} -> {:rewrite, rewritten}
              end
@@ -56,8 +92,8 @@ defmodule Volt.CSS.AssetURLRewriter do
     end
   end
 
-  defp rewrite_build_url(url, {assets, emitted}, source_path, outdir, prefix, opts) do
-    case build_url(url, source_path, outdir, prefix, emitted, opts) do
+  defp rewrite_build_url(url, {assets, emitted}, source_path, prefix, opts) do
+    case build_url(url, source_path, prefix, emitted, opts) do
       {:ok, ^url, emitted, _asset} ->
         {:keep, {assets, emitted}}
 
@@ -67,13 +103,13 @@ defmodule Volt.CSS.AssetURLRewriter do
     end
   end
 
-  defp build_url(url, source_path, outdir, prefix, emitted, opts) do
+  defp build_url(url, source_path, prefix, emitted, opts) do
     if rewrite_candidate?(url) do
       uri = URI.parse(url)
       asset_path = Path.expand(uri.path || "", Path.dirname(source_path))
 
       if Volt.Assets.asset?(asset_path) and File.regular?(asset_path) do
-        {filename, asset, emitted} = emitted_filename(asset_path, outdir, emitted, opts)
+        {filename, asset, emitted} = emitted_filename(asset_path, emitted, opts)
         {:ok, append_suffix(Volt.URL.join(prefix, filename), uri), emitted, asset}
       else
         {:ok, url, emitted, nil}
@@ -83,15 +119,23 @@ defmodule Volt.CSS.AssetURLRewriter do
     end
   end
 
-  defp dev_url(url, source_path, root, prefix) do
+  defp dev_url(url, source_path, root, prefix, opts) do
     if rewrite_candidate?(url) do
       uri = URI.parse(url)
       asset_path = Path.expand(uri.path || "", Path.dirname(source_path))
 
-      if Volt.Assets.asset?(asset_path) and File.regular?(asset_path) and
-           Volt.Path.inside?(asset_path, root) do
-        relative = Path.relative_to(asset_path, root)
-        {:ok, append_suffix(Volt.URL.join(prefix, relative), uri)}
+      if Volt.Assets.asset?(asset_path) and File.regular?(asset_path) do
+        cond do
+          Volt.Path.inside?(asset_path, root) ->
+            relative = Path.relative_to(asset_path, root)
+            {:ok, append_suffix(Volt.URL.join(prefix, relative), uri)}
+
+          grant = Keyword.get(opts, :grant_asset) ->
+            {:ok, append_suffix(grant.(asset_path), uri)}
+
+          true ->
+            {:ok, url}
+        end
       else
         {:ok, url}
       end
@@ -100,15 +144,16 @@ defmodule Volt.CSS.AssetURLRewriter do
     end
   end
 
-  defp emitted_filename(asset_path, outdir, emitted, opts) do
+  defp emitted_filename(asset_path, emitted, opts) do
     case Map.fetch(emitted, asset_path) do
-      {:ok, {filename, asset}} ->
+      {:ok, {filename, asset, _artifact}} ->
         {filename, asset, emitted}
 
       :error ->
-        {:ok, filename} = Volt.Assets.copy_hashed(asset_path, outdir)
+        artifact = Volt.Assets.prepare_hashed(asset_path)
+        filename = artifact.file
         asset = Volt.Assets.manifest_asset(asset_path, filename, root: Keyword.get(opts, :root))
-        {filename, asset, Map.put(emitted, asset_path, {filename, asset})}
+        {filename, asset, Map.put(emitted, asset_path, {filename, asset, artifact})}
     end
   end
 
diff --git a/lib/volt/css/imports.ex b/lib/volt/css/imports.ex
index 43853f7..16e728f 100644
--- a/lib/volt/css/imports.ex
+++ b/lib/volt/css/imports.ex
@@ -36,6 +36,8 @@ defmodule Volt.CSS.Imports do
          {:ok, imported_css} <- File.read(resolved),
          {:ok, imported_css} <-
            do_inline(imported_css, resolved, opts, MapSet.put(seen, resolved)),
+         {:ok, imported_css} <-
+           Volt.CSS.AssetURLRewriter.rebase(imported_css, resolved, Path.dirname(source_path)),
          {:ok, {rule_start, rule_end}} <- import_rule_bounds(css, dependency) do
       {:ok, replace_range(css, rule_start, rule_end, imported_css <> "\n")}
     else
diff --git a/lib/volt/dev.ex b/lib/volt/dev.ex
index c3ef3dc..d85e177 100644
--- a/lib/volt/dev.ex
+++ b/lib/volt/dev.ex
@@ -12,7 +12,7 @@ defmodule Volt.Dev do
   def ensure_watcher(opts) when is_list(opts) do
     result =
       if dev_supervision_started?() do
-        start_watcher(opts)
+        start(opts)
       else
         {:error, :not_started}
       end
@@ -26,23 +26,132 @@ defmodule Volt.Dev do
     end
   end
 
-  defp start_watcher(opts) do
-    {id, opts} = Keyword.pop(opts, :id, :default)
-    key = {:watcher, id, opts |> Keyword.fetch!(:root) |> Path.expand()}
+  @doc "Start a supervised generation with a state owner and watcher."
+  def start_supervised_session(session, opts) when session != :default do
+    watcher_opts = opts |> Keyword.put(:session, session) |> Keyword.put(:name, nil)
+    Volt.Dev.Session.Supervisor.start_link(identity: session, watcher: watcher_opts)
+  end
+
+  @doc "Start or reuse a managed watcher, rejecting conflicting configuration."
+  def start(opts) do
+    session = session_identity(opts)
+    root = opts |> Keyword.fetch!(:root) |> Volt.Paths.expand()
+    key = {:session, session}
+    opts = normalize_options(Keyword.put(opts, :session, session), root)
+
+    :global.trans(
+      {{__MODULE__, key}, self()},
+      fn ->
+        Volt.Dev.Session.Call.run(fn -> start_watcher(key, opts) end)
+      end,
+      [node()]
+    )
+  end
+
+  defp start_watcher({:session, session} = key, opts) do
     name = {:via, Registry, {@registry, key}}
 
-    case Registry.lookup(@registry, key) do
-      [{pid, _}] ->
-        {:ok, pid}
+    result =
+      case GenServer.whereis(name) do
+        nil ->
+          spec =
+            Supervisor.child_spec(
+              {Volt.Dev.Session.Supervisor,
+               [name: name, identity: session, watcher: Keyword.put(opts, :name, nil)]},
+              restart: :transient
+            )
+
+          DynamicSupervisor.start_child(@supervisor, spec)
+
+        pid ->
+          {:ok, pid}
+      end
 
+    case result do
+      {:ok, supervisor} -> verify_session(supervisor, opts)
+      {:error, {:already_started, supervisor}} -> verify_session(supervisor, opts)
+      error -> error
+    end
+  end
+
+  @doc "Normalize omitted session identity from profile and asset root."
+  def session_identity(opts) do
+    case Keyword.get(opts, :session, :default) do
+      :default ->
+        {:managed, Keyword.get(opts, :id, :default),
+         Volt.Paths.expand(Keyword.fetch!(opts, :root))}
+
+      session ->
+        session
+    end
+  end
+
+  defp verify_session(supervisor, opts) do
+    case Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+           id == Volt.Dev.Session.Watcher
+         end) do
+      {_, pid, _, _} when is_pid(pid) -> verify_configuration(supervisor, pid, opts)
+      _ -> {:error, :session_restarting}
+    end
+  end
+
+  @doc "Read CSS from the worker owned by a managed session."
+  def stylesheet(session) do
+    case Registry.lookup(@registry, {:session, session}) do
+      [{supervisor, _}] -> Volt.Dev.Session.Supervisor.stylesheet(supervisor)
+      [] -> {:error, :session_not_started}
+    end
+  end
+
+  @doc "Resolve the current owned generation for an explicitly identified session."
+  def tables(session) when session != :default do
+    case Registry.lookup(@registry, {:session, session}) do
+      [{supervisor, _}] -> Volt.Dev.Session.Supervisor.tables(supervisor)
+      [] -> {:error, :session_not_started}
+    end
+  end
+
+  @doc "Stop an explicitly identified session and clear its compilation state."
+  def stop(:default), do: {:error, :explicit_session_required}
+
+  def stop(session) do
+    :global.trans({{__MODULE__, {:session, session}}, self()}, fn -> stop_session(session) end, [
+      node()
+    ])
+  end
+
+  defp stop_session(session) do
+    case Registry.lookup(@registry, {:session, session}) do
       [] ->
-        opts = Keyword.put(opts, :name, name)
+        :ok
 
-        case DynamicSupervisor.start_child(@supervisor, {Volt.Watcher, opts}) do
-          {:error, {:already_started, pid}} -> {:ok, pid}
+      [{pid, _}] ->
+        case DynamicSupervisor.terminate_child(@supervisor, pid) do
+          {:error, :not_found} -> :ok
           result -> result
         end
     end
+
+    Volt.Dev.Cleanup.run(session)
+  end
+
+  defp normalize_options(opts, root) do
+    opts
+    |> Keyword.delete(:id)
+    |> Keyword.put(:root, root)
+    |> Keyword.put_new(:session, :default)
+    |> Keyword.update(:watch_dirs, [], &Enum.map(&1, fn path -> Volt.Paths.expand(path) end))
+    |> Keyword.update(:reload_dirs, [], &Enum.map(&1, fn path -> Volt.Paths.expand(path) end))
+  end
+
+  defp verify_configuration(supervisor, pid, opts) do
+    signature = opts |> Keyword.drop([:name, :managed_key]) |> Map.new()
+
+    with %Volt.Dev.Session.Tables{} = tables <- Volt.Dev.Session.Supervisor.tables(supervisor) do
+      if Volt.Dev.Session.State.configuration_matches?(tables.owner, signature),
+        do: {:ok, pid},
+        else: {:error, :session_configuration_conflict}
+    end
   end
 
   defp dev_supervision_started? do
diff --git a/lib/volt/dev/assets.ex b/lib/volt/dev/assets.ex
new file mode 100644
index 0000000..333f922
--- /dev/null
+++ b/lib/volt/dev/assets.ex
@@ -0,0 +1,34 @@
+defmodule Volt.Dev.Assets do
+  @moduledoc "Session-owned URL grants for assets resolved from project stylesheets."
+
+  @table :volt_dev_assets
+  @prefix "/@volt/assets/"
+
+  def create_table do
+    :ets.new(@table, [:named_table, :set, :public, read_concurrency: true])
+    :ok
+  end
+
+  @doc "Grant a browser URL to an already resolved asset; never accepts browser-supplied paths."
+  def register(path, session) do
+    path = Path.expand(path)
+    id = :crypto.hash(:sha256, path) |> Base.encode16(case: :lower)
+    {table, key} = location(session, id)
+    :ets.insert(table, {key, path})
+    @prefix <> id
+  end
+
+  def fetch(id, session) do
+    {table, key} = location(session, id)
+
+    case :ets.lookup(table, key) do
+      [{^key, path}] -> {:ok, path}
+      [] -> :error
+    end
+  end
+
+  def clear_session(session), do: Volt.ETS.clear_session(@table, session)
+
+  defp location(%Volt.Dev.Session.Tables{assets: table}, id), do: {table, id}
+  defp location(session, id), do: {@table, {session, id}}
+end
diff --git a/lib/volt/dev/cleanup.ex b/lib/volt/dev/cleanup.ex
new file mode 100644
index 0000000..7fdd716
--- /dev/null
+++ b/lib/volt/dev/cleanup.ex
@@ -0,0 +1,16 @@
+defmodule Volt.Dev.Cleanup do
+  @moduledoc "Cleanup of session-scoped compilation and dependency state."
+
+  def run(session) do
+    Volt.Dev.Assets.clear_session(session)
+    Volt.Tailwind.Supervisor.release_runtime(session)
+    Volt.Cache.clear_session(session)
+    Volt.HMR.ImportGraph.clear_session(session)
+    Volt.HMR.GlobGraph.clear_session(session)
+    Volt.HMR.StyleGraph.clear_session(session)
+    Volt.HMR.ModuleGraph.clear_session(session)
+    Volt.HMR.Errors.clear_session(session)
+    Volt.HMR.Documents.clear_session(session)
+    :ok
+  end
+end
diff --git a/lib/volt/dev/console_forwarder.ex b/lib/volt/dev/console_forwarder.ex
index 81fe6b0..b60b08f 100644
--- a/lib/volt/dev/console_forwarder.ex
+++ b/lib/volt/dev/console_forwarder.ex
@@ -9,7 +9,7 @@ defmodule Volt.Dev.ConsoleForwarder do
   defmodule Payload do
     @moduledoc false
 
-    use JSONCodec, fast_path: :json
+    use JSONCodec
 
     defstruct [:level, :source, :args]
 
diff --git a/lib/volt/dev/error.ex b/lib/volt/dev/error.ex
new file mode 100644
index 0000000..a40706c
--- /dev/null
+++ b/lib/volt/dev/error.ex
@@ -0,0 +1,179 @@
+defmodule Volt.Dev.Error do
+  @moduledoc """
+  JSON-safe error entries for the development error overlay.
+
+  Build errors arrive as `OXC.Diagnostic` maps, compiler messages, exceptions, or
+  arbitrary terms. `entries/2` turns any of them into maps the browser overlay
+  renders, with a source frame when the file and line are known.
+
+  With the optional `:lumis` dependency and a Lumis parser package for the file's
+  language, such as `:lumis_wasm_typescript`, entries also carry `frame_html`, the
+  frame with syntax highlighting.
+  """
+
+  @type entry :: %{
+          title: String.t(),
+          message: String.t(),
+          file: String.t() | nil,
+          line: pos_integer() | nil,
+          column: pos_integer() | nil,
+          hint: String.t() | nil,
+          frame: String.t() | nil,
+          frame_html: String.t() | nil,
+          stack: String.t() | nil
+        }
+
+  @doc """
+  Build overlay entries from an error `reason`.
+
+  ## Options
+
+    * `:file` — the source path the errors belong to. It names entries that have
+      no file or only its basename, and is read for source frames.
+    * `:title` — the overlay heading for these errors. Default: `"Build error"`
+  """
+  @spec entries(term(), keyword()) :: [entry()]
+  def entries(reason, opts \\ [])
+
+  def entries(errors, opts) when is_list(errors), do: Enum.flat_map(errors, &entries(&1, opts))
+
+  def entries(%{__exception__: true} = exception, opts),
+    do: [entry(Exception.message(exception), opts, [])]
+
+  def entries(%{message: message} = diagnostic, opts) when is_binary(message) do
+    {line, column} = position(Map.get(diagnostic, :position))
+    hint = if is_binary(Map.get(diagnostic, :details)), do: diagnostic.details
+
+    stack =
+      case Map.get(diagnostic, :stacktrace) do
+        [_ | _] = stacktrace -> Exception.format_stacktrace(stacktrace)
+        _none -> nil
+      end
+
+    [
+      entry(message, opts,
+        file: Map.get(diagnostic, :file),
+        line: line,
+        column: column,
+        hint: hint,
+        stack: stack
+      )
+    ]
+  end
+
+  def entries(message, opts) when is_binary(message), do: [entry(message, opts, [])]
+  def entries(reason, opts), do: [entry(inspect(reason), opts, [])]
+
+  defp entry(message, opts, fields) do
+    file = source_file(fields[:file], opts[:file])
+    line = fields[:line]
+    column = fields[:column]
+    {frame, frame_html} = frames(file, line, column)
+
+    %{
+      title: opts[:title] || "Build error",
+      message: message,
+      file: file && Path.relative_to_cwd(file),
+      line: line,
+      column: column,
+      hint: fields[:hint],
+      frame: frame,
+      frame_html: frame_html,
+      stack: fields[:stack]
+    }
+  end
+
+  defp source_file(nil, path), do: path
+  defp source_file(file, nil), do: file
+
+  defp source_file(file, path) do
+    if file == Path.basename(path), do: path, else: file
+  end
+
+  defp position({line, column}), do: {line, column}
+  defp position(line) when is_integer(line) and line > 0, do: {line, nil}
+  defp position(_position), do: {nil, nil}
+
+  defp frames(file, line, column) when is_binary(file) and is_integer(line) do
+    with {:ok, source} <- File.read(file),
+         lines = String.split(source, ~r/\r?\n/),
+         true <- line <= length(lines) do
+      first = max(line - 2, 1)
+      last = min(line + 1, length(lines))
+      width = last |> Integer.to_string() |> byte_size()
+      frame = %{first: first, line: line, column: column, width: width}
+      texts = Enum.slice(lines, (first - 1)..(last - 1)//1)
+
+      {render(frame, texts, & &1), highlighted_frame(file, source, frame, texts)}
+    else
+      _ -> {nil, nil}
+    end
+  end
+
+  defp frames(_file, _line, _column), do: {nil, nil}
+
+  defp render(frame, texts, gutter) do
+    texts
+    |> Enum.with_index(frame.first)
+    |> Enum.flat_map(fn {text, number} ->
+      marker = if number == frame.line, do: ">", else: " "
+      padded = number |> Integer.to_string() |> String.pad_leading(frame.width)
+      row = gutter.("#{marker} #{padded} | ") <> text
+
+      if number == frame.line and frame.column do
+        blank = String.duplicate(" ", frame.width)
+        [row, gutter.("  #{blank} | #{String.duplicate(" ", frame.column - 1)}^")]
+      else
+        [row]
+      end
+    end)
+    |> Enum.join("\n")
+  end
+
+  if Code.ensure_loaded?(Lumis) do
+    @theme "github_dark"
+
+    defp highlighted_frame(file, source, frame, texts) do
+      last = frame.first + length(texts) - 1
+
+      with [_ | _] = highlighted <- highlight(file, source, frame.first..last//1) do
+        # Lumis leaves out a trailing empty line.
+        highlighted = highlighted ++ List.duplicate("", length(texts) - length(highlighted))
+        render(frame, highlighted, &html_gutter/1)
+      end
+    end
+
+    # The error line's marker and caret stand out; other gutters are dim.
+    defp html_gutter(gutter) do
+      color = if String.contains?(gutter, [">", "^"]), do: "#ff6b9a", else: "#6b5b8f"
+      ~s(<span style="color:#{color}">#{String.replace(gutter, ">", "&gt;")}</span>)
+    end
+
+    # Highlights the whole file, so tokens that span lines keep their colors, and
+    # keeps the lines in `range`. Nil when no Lumis parser covers the language.
+    defp highlight(file, source, range) do
+      language = Lumis.Languages.guess(file, source)
+      formatter = {:html_inline, language: language, theme: @theme}
+
+      with true <- language != "plaintext",
+           :ok <- Lumis.Languages.load(language),
+           {:ok, html} <- Lumis.highlight(source, formatter: formatter) do
+        html
+        |> String.split("\n")
+        |> Enum.slice((range.first - 1)..(range.last - 1)//1)
+        |> Enum.map(&line_html/1)
+      else
+        _ -> nil
+      end
+    end
+
+    defp line_html(line) do
+      case Regex.run(~r{<span class="l-line"[^>]*>(.*)</span>}, line, capture: :all_but_first) do
+        [html] -> html
+        nil -> ""
+      end
+    end
+  else
+    defp highlighted_frame(_file, _source, _frame, _texts), do: nil
+  end
+end
diff --git a/lib/volt/dev/prebundled.ex b/lib/volt/dev/prebundled.ex
new file mode 100644
index 0000000..2201052
--- /dev/null
+++ b/lib/volt/dev/prebundled.ex
@@ -0,0 +1,38 @@
+defmodule Volt.Dev.Prebundled do
+  @moduledoc false
+  # Which sets of vendor options have been pre-bundled since the sources last
+  # changed.
+  #
+  # Phoenix initializes plugs on every request in development, so the dev
+  # server asks for a pre-bundle on every request. Scanning the sources each
+  # time is wasted work, and concurrent requests bundling at once would replace
+  # cache files that others are reading.
+
+  @table :volt_vendor_prebundled
+
+  def create_table, do: Volt.ETS.create_named_set(@table)
+
+  @doc """
+  Run `prebundle` unless it already ran for `opts` since `forget/0`. Callers
+  with the same options take turns, so one bundles and the rest find it done.
+  """
+  @spec ensure(keyword(), (-> term())) :: :ok
+  def ensure(opts, prebundle) when is_function(prebundle, 0) do
+    :global.trans(
+      {{__MODULE__, opts}, self()},
+      fn ->
+        if :ets.lookup(@table, opts) == [] do
+          prebundle.()
+          Volt.ETS.put(@table, {opts})
+        end
+      end,
+      [node()]
+    )
+
+    :ok
+  end
+
+  @doc "Make `ensure/2` run again. A changed source may import a package that is not bundled yet."
+  @spec forget() :: :ok
+  def forget, do: Volt.ETS.clear(@table)
+end
diff --git a/lib/volt/dev/session/call.ex b/lib/volt/dev/session/call.ex
new file mode 100644
index 0000000..0bb8694
--- /dev/null
+++ b/lib/volt/dev/session/call.ex
@@ -0,0 +1,13 @@
+defmodule Volt.Dev.Session.Call do
+  @moduledoc "Translate disappearing session processes into a retryable lifecycle result."
+
+  def run(fun) do
+    fun.()
+  catch
+    :exit, {reason, {GenServer, :call, _}} when reason in [:noproc, :normal, :shutdown] ->
+      {:error, :session_restarting}
+
+    :exit, {{:shutdown, _}, {GenServer, :call, _}} ->
+      {:error, :session_restarting}
+  end
+end
diff --git a/lib/volt/dev/session/state.ex b/lib/volt/dev/session/state.ex
new file mode 100644
index 0000000..8d730fd
--- /dev/null
+++ b/lib/volt/dev/session/state.ex
@@ -0,0 +1,42 @@
+defmodule Volt.Dev.Session.State do
+  @moduledoc "Owns the compilation tables for one development-session generation."
+
+  use GenServer
+  alias Volt.Dev.Session.Tables
+
+  defstruct [:tables, :configuration]
+
+  def start_link(opts) do
+    {configuration, opts} = Keyword.pop(opts, :configuration)
+    GenServer.start_link(__MODULE__, configuration, opts)
+  end
+
+  def configuration_matches?(server, signature),
+    do: GenServer.call(server, {:configuration_matches, signature})
+
+  def tables(server), do: GenServer.call(server, :tables)
+
+  def attach_stylesheet(server, worker), do: GenServer.call(server, {:attach_stylesheet, worker})
+
+  @impl true
+  def init(configuration) do
+    tables =
+      Map.new([:cache, :imports, :globs, :styles, :modules, :assets], fn kind ->
+        {kind, :ets.new(kind, [:set, :public, read_concurrency: true])}
+      end)
+
+    tables = struct!(Tables, Map.merge(tables, %{owner: self(), generation: make_ref()}))
+    {:ok, %__MODULE__{tables: tables, configuration: configuration}}
+  end
+
+  @impl true
+  def handle_call(:tables, _from, state), do: {:reply, state.tables, state}
+
+  def handle_call({:configuration_matches, signature}, _from, state),
+    do: {:reply, state.configuration == signature, state}
+
+  def handle_call({:attach_stylesheet, worker}, _from, state) do
+    tables = %{state.tables | stylesheet_worker: worker}
+    {:reply, tables, %{state | tables: tables}}
+  end
+end
diff --git a/lib/volt/dev/session/supervisor.ex b/lib/volt/dev/session/supervisor.ex
new file mode 100644
index 0000000..0123cee
--- /dev/null
+++ b/lib/volt/dev/session/supervisor.ex
@@ -0,0 +1,69 @@
+defmodule Volt.Dev.Session.Supervisor do
+  @moduledoc "Supervision boundary for a development session's state and dependent services."
+
+  use Supervisor
+
+  def start_link(opts) do
+    {name, opts} = Keyword.pop(opts, :name)
+    Supervisor.start_link(__MODULE__, opts, if(name, do: [name: name], else: []))
+  end
+
+  @doc "Read the current generation from a running session subtree."
+  def tables(supervisor), do: Volt.Dev.Session.Call.run(fn -> read_tables(supervisor) end)
+
+  defp read_tables(supervisor) do
+    case Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+           id == Volt.Dev.Session.State
+         end) do
+      {_, pid, _, _} when is_pid(pid) -> Volt.Dev.Session.State.tables(pid)
+      _ -> {:error, :session_restarting}
+    end
+  end
+
+  @doc "Read the session's last successful stylesheet."
+  def stylesheet(supervisor), do: Volt.Dev.Session.Call.run(fn -> read_stylesheet(supervisor) end)
+
+  defp read_stylesheet(supervisor) do
+    case Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+           id == Volt.Tailwind.Worker
+         end) do
+      {_, pid, _, _} when is_pid(pid) -> Volt.Tailwind.Worker.stylesheet(pid)
+      _ -> {:error, :session_restarting}
+    end
+  end
+
+  @impl true
+  def init(opts) do
+    # State must start first. Its replacement invalidates every dependent child's handles.
+    children =
+      case Keyword.fetch(opts, :watcher) do
+        {:ok, watcher_opts} ->
+          identity = Keyword.fetch!(opts, :identity)
+          owner_name = {:via, Registry, {Volt.Dev.WatcherRegistry, {:state_owner, identity}}}
+
+          runtime_name = {:via, Registry, {Volt.Dev.WatcherRegistry, {:compiler, identity}}}
+
+          worker_name = {:via, Registry, {Volt.Dev.WatcherRegistry, {:stylesheet, identity}}}
+
+          [
+            {Volt.Dev.Session.State,
+             name: owner_name,
+             configuration: watcher_opts |> Keyword.drop([:name, :managed_key]) |> Map.new()},
+            {Volt.Tailwind.Runtime, name: runtime_name},
+            {Volt.Tailwind.Worker,
+             name: worker_name, key: {:session, identity}, runtime: runtime_name},
+            {Volt.Dev.Session.Watcher,
+             watcher_opts
+             |> Keyword.put(:tailwind_outdir, Keyword.get(watcher_opts, :tailwind_sink))
+             |> Keyword.put(:state_owner, owner_name)
+             |> Keyword.put(:tailwind_worker, worker_name)
+             |> Keyword.put(:tailwind_runtime, runtime_name)}
+          ]
+
+        :error ->
+          [{Volt.Dev.Session.State, []} | Keyword.get(opts, :children, [])]
+      end
+
+    Supervisor.init(children, strategy: :rest_for_one, auto_shutdown: :any_significant)
+  end
+end
diff --git a/lib/volt/dev/session/tables.ex b/lib/volt/dev/session/tables.ex
new file mode 100644
index 0000000..065abcf
--- /dev/null
+++ b/lib/volt/dev/session/tables.ex
@@ -0,0 +1,6 @@
+defmodule Volt.Dev.Session.Tables do
+  @moduledoc "Generation-specific handles to ETS tables owned by a development session."
+
+  @enforce_keys [:owner, :generation, :cache, :imports, :globs, :styles, :modules, :assets]
+  defstruct [{:stylesheet_worker, nil} | @enforce_keys]
+end
diff --git a/lib/volt/dev/session/watcher.ex b/lib/volt/dev/session/watcher.ex
new file mode 100644
index 0000000..39d0205
--- /dev/null
+++ b/lib/volt/dev/session/watcher.ex
@@ -0,0 +1,20 @@
+defmodule Volt.Dev.Session.Watcher do
+  @moduledoc "Starts a watcher using the current session-owned table handles."
+
+  def start_link(opts) do
+    {state_owner, opts} = Keyword.pop!(opts, :state_owner)
+    worker = GenServer.whereis(Keyword.fetch!(opts, :tailwind_worker))
+    tables = Volt.Dev.Session.State.attach_stylesheet(state_owner, worker)
+
+    Volt.Watcher.start_link(Keyword.put(opts, :tables, tables))
+  end
+
+  def child_spec(opts) do
+    %{
+      id: __MODULE__,
+      start: {__MODULE__, :start_link, [opts]},
+      restart: :transient,
+      significant: true
+    }
+  end
+end
diff --git a/lib/volt/dev_server.ex b/lib/volt/dev_server.ex
index 0097f42..cbd0933 100644
--- a/lib/volt/dev_server.ex
+++ b/lib/volt/dev_server.ex
@@ -19,6 +19,11 @@ defmodule Volt.DevServer do
     * `:target` — JS downlevel target (e.g. `:es2020`)
     * `:import_source` — JSX import source (e.g. `"vue"`)
     * `:vapor` — use Vue Vapor mode (default: `false`)
+    * `:document` — a function, or `{module, function, args}`, called with a
+      page's path, followed by `args`, to render the HTML a request for it is
+      answered with. With
+      it and the server's `:morph` setting, Volt compares renders for each open
+      page itself; see the HMR guide.
     * `:watch` — start the supervised file watcher on the first request (default: `true`)
 
   ## Example
@@ -32,7 +37,7 @@ defmodule Volt.DevServer do
   require Logger
 
   alias Plug.Conn
-  alias Volt.{Config, URL}
+  alias Volt.{Config, Paths, URL}
 
   @support_modules {:volt, "ts"}
   @runtime_rewrites %{"../hmr" => "/@volt/client.js"}
@@ -47,31 +52,64 @@ defmodule Volt.DevServer do
     server_config = Config.server(profile, build_opts)
 
     root = Keyword.get(opts, :root) || to_string(config.root)
-    expanded_root = Path.expand(root)
+    expanded_root = Paths.expand(root)
 
     node_modules = NPM.Resolution.PackageResolver.find_node_modules(expanded_root)
     plugins = config.plugins
     module_types = config.module_types
     tailwind_config = Config.tailwind(profile)
 
-    prebundle_vendor(expanded_root, node_modules, plugins, config.resolve_dirs, module_types)
+    tailwind_root =
+      if Volt.Config.Tailwind.enabled?(tailwind_config),
+        do: Volt.Config.Tailwind.new(tailwind_config)
 
-    watcher_opts =
+    session =
       if server_config.watch do
+        Volt.Dev.session_identity(
+          root: expanded_root,
+          id: profile || :default,
+          session: Keyword.get(opts, :session, :default)
+        )
+      else
+        Keyword.get(opts, :session, :default)
+      end
+
+    # A watcher says when sources change, so the scan can wait for that.
+    watched? = server_config.watch or not is_nil(Keyword.get(opts, :session_supervisor))
+
+    prebundle_vendor(
+      [
+        root: expanded_root,
+        node_modules: node_modules,
+        plugins: plugins,
+        resolve_dirs: config.resolve_dirs,
+        module_types: module_types
+      ],
+      watched?
+    )
+
+    watcher_opts =
+      if server_config.watch and is_nil(Keyword.get(opts, :session_supervisor)) do
         watch_dirs =
-          if tailwind_config != [] and server_config.watch_dirs == [] do
-            [Volt.Paths.lib()]
+          if tailwind_root && server_config.watch_dirs == [] do
+            [Paths.lib()]
           else
             server_config.watch_dirs
           end
 
         [
           id: profile || :default,
+          session: session,
           root: expanded_root,
           watch_dirs: watch_dirs,
           reload_dirs: server_config.reload_dirs,
-          tailwind: tailwind_config != [],
-          tailwind_css: tailwind_config[:css],
+          watch_ignored: server_config.watch_ignored,
+          tailwind_key: tailwind_key(profile, tailwind_root),
+          tailwind: not is_nil(tailwind_root),
+          tailwind_css: tailwind_root && tailwind_root.css,
+          tailwind_name: tailwind_root && tailwind_root.name,
+          tailwind_sources: tailwind_root && tailwind_root.sources,
+          tailwind_url: tailwind_root && tailwind_root.dev_url,
           tailwind_outdir: Path.join(to_string(config.outdir), "css"),
           target: config.target,
           import_source: config.import_source,
@@ -82,7 +120,11 @@ defmodule Volt.DevServer do
           resolve_dirs: config.resolve_dirs,
           module_types: module_types,
           define:
-            Volt.Env.define(mode: "development", root: File.cwd!(), env_prefix: config.env_prefix)
+            Volt.Env.define(
+              mode: "development",
+              root: Paths.root(),
+              env_prefix: config.env_prefix
+            )
         ]
       end
 
@@ -100,21 +142,176 @@ defmodule Volt.DevServer do
       resolve_dirs: config.resolve_dirs,
       module_types: module_types,
       define:
-        Volt.Env.define(mode: "development", root: File.cwd!(), env_prefix: config.env_prefix),
+        Volt.Env.define(
+          mode: "development",
+          root: Paths.root(),
+          env_prefix: config.env_prefix
+        ),
       hmr_timeout: server_config.hmr_timeout,
+      morph: server_config.morph,
+      document: Keyword.get(opts, :document),
+      stylesheet_url: tailwind_root && tailwind_root.dev_url,
+      stylesheet_source: tailwind_root && tailwind_root.css,
+      session_supervisor: Keyword.get(opts, :session_supervisor),
+      tables: Keyword.get(opts, :tables),
+      session: session,
       watcher_opts: watcher_opts
     }
   end
 
+  defp stylesheet_for_generation(%{stylesheet_worker: worker}) when is_pid(worker) do
+    Volt.Tailwind.Worker.stylesheet(worker)
+  catch
+    :exit, {:noproc, _} -> {:error, :session_restarting}
+    :exit, {:normal, _} -> {:error, :session_restarting}
+    :exit, {:shutdown, _} -> {:error, :session_restarting}
+  end
+
+  defp stylesheet_for_generation(_tables), do: {:error, :not_built}
+
+  defp tailwind_key(_profile, nil), do: nil
+  defp tailwind_key(profile, root), do: {:profile, profile || :default, root.css || root.name}
+
   @impl true
+  def call(conn, %{session_supervisor: supervisor} = config) when not is_nil(supervisor) do
+    case Volt.Dev.Session.Supervisor.tables(supervisor) do
+      %Volt.Dev.Session.Tables{} = tables ->
+        call_generation(conn, config, tables)
+
+      {:error, :session_restarting} ->
+        conn |> Conn.send_resp(503, "Development session is restarting") |> Conn.halt()
+    end
+  end
+
+  def call(conn, %{session: session, watcher_opts: opts} = config)
+      when session != :default and is_list(opts) do
+    with {:ok, _watcher} <- Volt.Dev.start(opts),
+         %Volt.Dev.Session.Tables{} = tables <- Volt.Dev.tables(session) do
+      call_generation(conn, config, tables)
+    else
+      {:error, reason} ->
+        session_unavailable(conn, reason)
+    end
+  end
+
+  def call(conn, %{session: session, tables: nil} = config) when session != :default do
+    case Volt.Dev.tables(session) do
+      %Volt.Dev.Session.Tables{} = tables ->
+        call_generation(conn, config, tables)
+
+      {:error, reason} ->
+        session_unavailable(conn, reason)
+    end
+  end
+
+  def call(conn, %{tables: %Volt.Dev.Session.Tables{} = tables} = config) do
+    call_generation(conn, config, tables)
+  end
+
   def call(conn, config) do
     Volt.Dev.ensure_watcher(config.watcher_opts)
     do_call(conn, config)
   end
 
+  defp session_unavailable(conn, reason) do
+    message = "Development session is unavailable: #{session_error(reason)}"
+    Logger.error("[Volt] " <> message)
+    conn |> Conn.send_resp(503, message) |> Conn.halt()
+  end
+
+  defp session_error(:session_configuration_conflict) do
+    "a Volt watcher is already running for this asset root with different options. " <>
+      "`plug Volt.DevServer` starts its own watcher, so remove any " <>
+      "`Mix.Tasks.Volt.Dev` entry from the endpoint's `:watchers` in config/dev.exs."
+  end
+
+  defp session_error(reason), do: inspect(reason)
+
+  defp call_generation(conn, config, tables) do
+    do_call(conn, %{config | tables: tables})
+  rescue
+    error in ArgumentError ->
+      case __STACKTRACE__ do
+        [{:ets, _operation, [table | _], _} | _]
+        when table in [
+               tables.cache,
+               tables.imports,
+               tables.globs,
+               tables.styles,
+               tables.modules,
+               tables.assets
+             ] ->
+          if :ets.info(table) == :undefined do
+            conn
+            |> Conn.send_resp(503, "Development session restarted; retry the request")
+            |> Conn.halt()
+          else
+            reraise error, __STACKTRACE__
+          end
+
+        _ ->
+          reraise error, __STACKTRACE__
+      end
+  end
+
+  defp do_call(
+         %Conn{request_path: path, method: method} = conn,
+         %{stylesheet_url: path, tables: %Volt.Dev.Session.Tables{}} = config
+       )
+       when is_binary(path) and method in ["GET", "HEAD"] do
+    result =
+      with {:ok, css} <- stylesheet_for_generation(config.tables) do
+        Volt.CSS.AssetURLRewriter.rewrite_dev(
+          css,
+          config.stylesheet_source,
+          config.root,
+          config.prefix,
+          grant_asset: &Volt.Dev.Assets.register(&1, config.tables)
+        )
+      end
+
+    case result do
+      {:ok, css} ->
+        conn
+        |> Conn.put_resp_content_type("text/css")
+        |> Conn.put_resp_header("cache-control", "no-store")
+        |> Conn.send_resp(200, if(method == "HEAD", do: "", else: css))
+        |> Conn.halt()
+
+      {:error, _} ->
+        conn |> Conn.send_resp(503, "Stylesheet is not ready") |> Conn.halt()
+    end
+  end
+
+  defp do_call(%Conn{request_path: "/@volt/assets/" <> id, method: method} = conn, config)
+       when method in ["GET", "HEAD"] do
+    case Volt.Dev.Assets.fetch(id, config.tables || config.session) do
+      {:ok, path} ->
+        if File.regular?(path) do
+          if method == "HEAD" do
+            conn
+            |> Conn.put_resp_content_type(Volt.Assets.mime_type(path))
+            |> Conn.send_resp(200, "")
+            |> Conn.halt()
+          else
+            serve_public(conn, path)
+          end
+        else
+          conn |> Conn.send_resp(404, "Asset not found") |> Conn.halt()
+        end
+
+      :error ->
+        conn |> Conn.send_resp(404, "Asset not registered for this session") |> Conn.halt()
+    end
+  end
+
   defp do_call(%Conn{request_path: "/@volt/ws"} = conn, config) do
     conn
-    |> WebSockAdapter.upgrade(Volt.HMR.Socket, [], timeout: config.hmr_timeout)
+    |> WebSockAdapter.upgrade(
+      Volt.HMR.Socket,
+      [session: config.session, document: config.document, morph: config.morph],
+      timeout: config.hmr_timeout
+    )
     |> Conn.halt()
   end
 
@@ -181,11 +378,20 @@ defmodule Volt.DevServer do
             serve(conn, relative, config)
 
           :no_match ->
-            conn
+            Volt.DevServer.ClientTag.register(conn, config.morph,
+              keep_for: document_session(config)
+            )
         end
     end
   end
 
+  # Served HTML is kept only when a page's websocket process will compare renders.
+  defp document_session(%{document: document, morph: morph, session: session})
+       when not is_nil(document) and morph != false,
+       do: session
+
+  defp document_session(_config), do: nil
+
   defp serve_virtual(conn, id, config) do
     case Volt.PluginRunner.load(config.plugins, id) do
       {:ok, source, content_type} ->
@@ -205,19 +411,25 @@ defmodule Volt.DevServer do
   defp compile_and_serve_virtual(conn, id, source, content_type, config) do
     case Volt.Pipeline.compile(id, source, pipeline_opts(config, id)) do
       {:ok, result} ->
+        Volt.HMR.clear_error(id, session: config.session)
         content_type = content_type || Volt.MIME.javascript()
         mod_url = virtual_url(id)
         code = code_for_request(result, mod_url, content_type, false)
 
-        update_module_graph(mod_url, id, id, code, source, content_type)
+        update_module_graph(
+          mod_url,
+          id,
+          id,
+          code,
+          source,
+          content_type,
+          config.tables || config.session
+        )
 
         send_compiled(conn, code, result.sourcemap, content_type)
 
       {:error, errors} ->
-        conn
-        |> Conn.put_resp_content_type(Volt.MIME.javascript())
-        |> Conn.send_resp(500, error_overlay(errors))
-        |> Conn.halt()
+        send_compile_error(conn, id, errors, config)
     end
   end
 
@@ -266,15 +478,24 @@ defmodule Volt.DevServer do
   defp compilable?(path, config),
     do: Path.extname(path) in Volt.JS.Extensions.compilable(config.plugins)
 
+  defp file_mtime(path) do
+    case File.stat(path, time: :posix) do
+      {:ok, %{mtime: mtime}} when is_integer(mtime) -> mtime
+      _ -> 0
+    end
+  end
+
   defp serve_compiled(conn, file_path, relative, config) do
     module_id = module_id_for_request(file_path, conn.query_string)
     request_relative = relative_for_module(relative, module_id)
-    mtime = Volt.Format.file_mtime(file_path)
+    mtime = file_mtime(file_path)
     css_import? = css_import_request?(conn, module_id)
     content_type = content_type_for(module_id, css_import?)
     cache_key = cache_key_for(module_id, css_import?)
 
-    case Volt.Cache.get(cache_key, mtime) do
+    # A compiled module imports vendor modules by their version, which changes
+    # when a package is installed or bundled again.
+    case current_cached(cache_key, mtime, config) do
       %{code: code, sourcemap: sourcemap} ->
         send_compiled(conn, code, sourcemap, content_type)
 
@@ -292,6 +513,16 @@ defmodule Volt.DevServer do
     end
   end
 
+  defp current_cached(cache_key, mtime, config) do
+    case Volt.Cache.get(cache_key, mtime, config.tables || config.session) do
+      %{vendor_hash: vendor_hash} = entry when is_binary(vendor_hash) ->
+        if vendor_hash == vendor_hash(config), do: entry
+
+      entry ->
+        entry
+    end
+  end
+
   defp compile_and_serve(
          conn,
          module_id,
@@ -305,37 +536,81 @@ defmodule Volt.DevServer do
     file_path = Volt.Plugin.EmbeddedModule.parent_path(module_id)
     source = File.read!(file_path)
 
-    case Volt.Pipeline.compile(module_id, source, pipeline_opts(config, module_id)) do
-      {:ok, result} ->
-        Volt.HMR.GlobGraph.update_from_source(file_path, source)
-        Volt.HMR.ImportGraph.update_from_compiled(file_path, result.code)
-        Volt.HMR.StyleDependencies.update_from_compile(file_path, source, result)
-
-        result = rewrite_dev_css_urls(result, file_path, config)
-        mod_url = Volt.URL.join(config.prefix, relative)
-        code = code_for_request(result, mod_url, content_type, css_import?)
-        graph_url = if css_import?, do: URL.append_query(mod_url, "import"), else: mod_url
-        update_module_graph(graph_url, graph_url, file_path, code, source, content_type)
-
-        entry = %Volt.DevServer.CacheEntry{
-          code: code,
-          sourcemap: result.sourcemap,
-          css: result.css,
-          hashes: result.hashes,
-          content_type: content_type
-        }
-
-        Volt.Cache.put(cache_key, mtime, entry)
-        send_compiled(conn, code, result.sourcemap, content_type)
-
+    with {:ok, module_source, cacheable?} <- module_source(file_path, source, config),
+         {:ok, result} <-
+           Volt.Pipeline.compile(module_id, module_source, pipeline_opts(config, module_id)) do
+      Volt.HMR.clear_error(file_path, session: config.session)
+      Volt.HMR.GlobGraph.update_from_source(file_path, source, config.tables || config.session)
+
+      Volt.HMR.ImportGraph.update_from_compiled(
+        file_path,
+        result.code,
+        config.tables || config.session
+      )
+
+      Volt.HMR.StyleDependencies.update_from_compile(
+        file_path,
+        source,
+        result,
+        config.tables || config.session
+      )
+
+      result = rewrite_dev_css_urls(result, file_path, config)
+      mod_url = Volt.URL.join(config.prefix, relative)
+      code = code_for_request(result, mod_url, content_type, css_import?)
+      graph_url = if css_import?, do: URL.append_query(mod_url, "import"), else: mod_url
+
+      update_module_graph(
+        graph_url,
+        graph_url,
+        file_path,
+        code,
+        source,
+        content_type,
+        config.tables || config.session
+      )
+
+      entry = %Volt.DevServer.CacheEntry{
+        code: code,
+        sourcemap: result.sourcemap,
+        css: result.css,
+        hashes: result.hashes,
+        content_type: content_type,
+        vendor_hash: vendor_hash(config)
+      }
+
+      if cacheable?,
+        do: Volt.Cache.put(cache_key, mtime, entry, config.tables || config.session)
+
+      send_compiled(conn, code, result.sourcemap, content_type)
+    else
       {:error, errors} ->
-        conn
-        |> Conn.put_resp_content_type(Volt.MIME.javascript())
-        |> Conn.send_resp(500, error_overlay(errors))
-        |> Conn.halt()
+        send_compile_error(conn, file_path, errors, config)
     end
   end
 
+  # CommonJS/UMD files are converted to ES modules, with the modules they
+  # require bundled in. Those are not tracked for invalidation, so a module
+  # that requires others is rebuilt on every request instead of cached.
+  defp module_source(file_path, source, config) do
+    if Volt.JS.CommonJS.commonjs?(source, file_path) do
+      opts = [
+        modules: Enum.reject([config.node_modules | config.resolve_dirs], &is_nil/1),
+        module_types: config.module_types
+      ]
+
+      with {:ok, code} <- Volt.JS.CommonJS.to_esm(file_path, opts) do
+        {:ok, code, not requires_modules?(source, file_path)}
+      end
+    else
+      {:ok, source, true}
+    end
+  end
+
+  defp requires_modules?(source, file_path) do
+    not match?({:ok, []}, OXC.select(source, Path.basename(file_path), :require_calls))
+  end
+
   defp pipeline_opts(config, importer) do
     [
       target: config.target,
@@ -352,7 +627,7 @@ defmodule Volt.DevServer do
     ]
   end
 
-  defp update_module_graph(mod_url, cache_key, file_path, code, source, content_type) do
+  defp update_module_graph(mod_url, cache_key, file_path, code, source, content_type, session) do
     imports =
       case OXC.select(code, Path.basename(file_path), :import_specifiers) do
         {:ok, imports} -> Enum.map(imports, &normalize_module_graph_import(&1, mod_url))
@@ -360,6 +635,7 @@ defmodule Volt.DevServer do
       end
 
     Volt.HMR.ModuleGraph.update_module(mod_url, cache_key, file_path, imports,
+      session: session,
       type: module_graph_type(content_type),
       self_accepting: Volt.HMR.Boundary.self_accepting?(source)
     )
@@ -517,14 +793,18 @@ defmodule Volt.DevServer do
   defp cache_key_for(file_path, false), do: file_path
 
   defp rewrite_dev_css_urls(%{type: :css, code: code} = result, file_path, config) do
-    case Volt.CSS.AssetURLRewriter.rewrite_dev(code, file_path, config.root, config.prefix) do
+    case Volt.CSS.AssetURLRewriter.rewrite_dev(code, file_path, config.root, config.prefix,
+           grant_asset: &Volt.Dev.Assets.register(&1, config.tables || config.session)
+         ) do
       {:ok, code} -> %{result | code: code}
       {:error, _} -> result
     end
   end
 
   defp rewrite_dev_css_urls(%{css: css} = result, file_path, config) when is_binary(css) do
-    case Volt.CSS.AssetURLRewriter.rewrite_dev(css, file_path, config.root, config.prefix) do
+    case Volt.CSS.AssetURLRewriter.rewrite_dev(css, file_path, config.root, config.prefix,
+           grant_asset: &Volt.Dev.Assets.register(&1, config.tables || config.session)
+         ) do
       {:ok, css} -> %{result | css: css}
       {:error, _} -> result
     end
@@ -583,12 +863,15 @@ defmodule Volt.DevServer do
     specifier = URL.append_query(specifier, query)
 
     cond do
-      NPM.Resolution.PackageResolver.node_builtin?(specifier) ->
+      Volt.JS.Specifier.node_builtin?(specifier) ->
         :keep
 
       String.starts_with?(specifier, "#") ->
         rewrite_package_import(specifier, importer, config)
 
+      Path.type(elem(URL.split_query(specifier), 0)) == :absolute ->
+        rewrite_resolved_path(specifier, config)
+
       NPM.Resolution.PackageResolver.relative?(specifier) ->
         rewrite_relative(specifier, importer, config)
 
@@ -694,33 +977,39 @@ defmodule Volt.DevServer do
 
   # ── Vendor pre-bundling ───────────────────────────────────────────
 
-  defp prebundle_vendor(root, node_modules, plugins, resolve_dirs, module_types) do
-    case Volt.JS.Vendor.prebundle(
-           root: root,
-           node_modules: node_modules,
-           plugins: plugins,
-           resolve_dirs: resolve_dirs,
-           module_types: module_types
-         ) do
-      {:ok, vendor_map} when map_size(vendor_map) > 0 ->
-        count = map_size(vendor_map)
-        Logger.debug("[Volt] Pre-bundled #{count} vendor package(s)")
+  defp prebundle_vendor(opts, true),
+    do: Volt.Dev.Prebundled.ensure(opts, fn -> Volt.JS.Vendor.prebundle(opts) end)
 
-      _ ->
-        :ok
-    end
-  end
+  defp prebundle_vendor(opts, false), do: Volt.JS.Vendor.prebundle(opts)
+
+  defp vendor_hash(config), do: Volt.JS.Vendor.browser_hash(vendor_opts(config))
 
   defp serve_vendor(specifier, config, browser_hash) do
     vendor_opts = vendor_opts(config)
 
     if Volt.JS.Vendor.current_browser_hash?(browser_hash, vendor_opts) do
-      read_or_bundle_vendor(specifier, config, vendor_opts)
+      with {:ok, code} <- read_or_bundle_vendor(specifier, config, vendor_opts) do
+        {:ok, version_vendor_imports(code, Volt.JS.Vendor.browser_hash(vendor_opts))}
+      end
     else
       {:error, :outdated}
     end
   end
 
+  # Pre-bundles import their siblings and shared chunks relatively. Application
+  # modules import the same files with the browser hash, and a browser treats
+  # URLs that differ only in their query as separate module instances.
+  defp version_vendor_imports(code, browser_hash) do
+    case OXC.rewrite_specifiers(code, "vendor.js", fn specifier ->
+           if NPM.Resolution.PackageResolver.relative?(specifier),
+             do: {:rewrite, URL.append_query(specifier, "v=#{browser_hash}")},
+             else: :keep
+         end) do
+      {:ok, rewritten} -> rewritten
+      {:error, _} -> code
+    end
+  end
+
   defp read_or_bundle_vendor(specifier, config, vendor_opts) do
     case Volt.JS.Vendor.read(specifier, vendor_opts) do
       {:ok, _} = ok ->
@@ -746,41 +1035,25 @@ defmodule Volt.DevServer do
     if Volt.MIME.javascript?(content_type), do: Volt.Dev.ConsoleForwarder.inject(code), else: code
   end
 
-  defp error_overlay(errors) do
-    msg =
-      errors
-      |> List.wrap()
-      |> Enum.map_join("\n", fn
-        %{message: m} -> m
-        e when is_binary(e) -> e
-        e -> inspect(e)
-      end)
+  # The HMR client shows the errors: a failed module fails its importers before
+  # any script in this response could run.
+  defp send_compile_error(conn, path, errors, config) do
+    Volt.HMR.error(path, errors, session: config.session)
+    message = "[Volt] Could not compile #{Path.relative_to(path, Paths.root())}"
 
-    overlay = support_module!("client/overlay.ts")
-    overlay <> "\n" <> error_overlay_invocation(msg)
-  end
-
-  defp error_overlay_invocation(message) do
-    "renderErrorOverlay($message, $options)"
-    |> OXC.parse!("volt-error-overlay-call.ts")
-    |> OXC.bind(message: {:literal, message}, options: {:literal, %{title: "Compilation error"}})
-    |> OXC.codegen!()
+    conn
+    |> Conn.put_resp_content_type(Volt.MIME.javascript())
+    |> Conn.send_resp(500, "throw new Error(#{Jason.encode!(message)})")
+    |> Conn.halt()
   end
 
   defp client_module!(heartbeat_interval) do
-    entry = Volt.Priv.path(@support_modules, "client/hmr.ts")
-
-    case Volt.JS.Runtime.Bundler.bundle_file(entry,
-           format: :esm,
-           define: %{"__VOLT_HEARTBEAT__" => Integer.to_string(heartbeat_interval)}
-         ) do
-      {:ok, code} when is_binary(code) -> code
-      {:error, reason} -> raise "Could not bundle Volt dev client: #{inspect(reason)}"
-    end
+    Volt.Priv.bundle!(@support_modules, "client/hmr.ts",
+      format: :esm,
+      define: %{"__VOLT_HEARTBEAT__" => Integer.to_string(heartbeat_interval)}
+    )
   end
 
-  defp support_module!(relative), do: Volt.Priv.js!(@support_modules, relative)
-
   defp support_module!(relative, bindings) do
     Volt.Priv.js!(@support_modules, relative, bindings, rewrite_specifiers: @runtime_rewrites)
   end
diff --git a/lib/volt/dev_server/cache_entry.ex b/lib/volt/dev_server/cache_entry.ex
index 44239d5..ecf84db 100644
--- a/lib/volt/dev_server/cache_entry.ex
+++ b/lib/volt/dev_server/cache_entry.ex
@@ -5,13 +5,15 @@ defmodule Volt.DevServer.CacheEntry do
             sourcemap: nil,
             css: nil,
             hashes: nil,
-            content_type: Volt.MIME.javascript()
+            content_type: Volt.MIME.javascript(),
+            vendor_hash: nil
 
   @type t :: %__MODULE__{
           code: String.t(),
           sourcemap: String.t() | nil,
           css: String.t() | nil,
           hashes: Volt.Pipeline.Result.Hashes.t() | nil,
-          content_type: String.t()
+          content_type: String.t(),
+          vendor_hash: String.t() | nil
         }
 end
diff --git a/lib/volt/dev_server/client_tag.ex b/lib/volt/dev_server/client_tag.ex
new file mode 100644
index 0000000..2121faa
--- /dev/null
+++ b/lib/volt/dev_server/client_tag.ex
@@ -0,0 +1,94 @@
+defmodule Volt.DevServer.ClientTag do
+  @moduledoc false
+  # Loads the HMR client as its own script in HTML pages, as Vite does. Modules
+  # also import the client, but a module that fails to compile stops its whole
+  # graph from running, and the client must still show the error overlay.
+
+  alias Plug.Conn
+
+  alias Volt.HMR.Document
+
+  @client "/@volt/client.js"
+  @src ~s(src="#{@client}")
+
+  @doc """
+  Add the dev client to the HTML this connection sends.
+
+  `morph` is the server's `:morph` setting: `false`, `true`, or
+  `[preserve: selector]`. With `keep_for: session`, the HTML of a successful
+  page is kept for the websocket process of the page to start from.
+  """
+  @spec register(Conn.t(), boolean() | keyword(), keyword()) :: Conn.t()
+  def register(conn, morph \\ false, opts \\ []) do
+    Conn.register_before_send(conn, &inject(&1, morph, Keyword.get(opts, :keep_for)))
+  end
+
+  defp inject(%Conn{resp_body: body} = conn, morph, session) when not is_nil(body) do
+    if html?(conn),
+      do: inject_client(conn, IO.iodata_to_binary(body), morph, session),
+      else: conn
+  end
+
+  defp inject(conn, _morph, _session), do: conn
+
+  # Successful pages carry an entity tag so the client can revalidate them
+  # instead of reloading; see `Volt.HMR.Document`.
+  defp inject_client(%Conn{status: 200} = conn, html, morph, session) do
+    etag = Document.etag(html)
+
+    if Document.fresh?(conn, etag) do
+      %{conn | status: 304, resp_body: ""}
+    else
+      if session, do: Volt.HMR.Documents.put(session, etag, html)
+      conn = Conn.put_resp_header(conn, "etag", etag)
+      %{conn | resp_body: tag(html, etag, morph)}
+    end
+  end
+
+  defp inject_client(conn, html, _morph, _session), do: %{conn | resp_body: put_client(html, "")}
+
+  @doc """
+  Add the dev client to a successful page, with the page's entity tag and the
+  server's `:morph` setting, as a response sent through the dev server has them.
+  """
+  @spec tag(String.t(), String.t(), boolean() | keyword()) :: String.t()
+  def tag(html, etag, morph) do
+    put_client(html, attribute(Document.attribute(), etag) <> morph_attribute(morph))
+  end
+
+  # A page may already load the client, as pages rendered by a site generator
+  # do. Its tag gets the attributes; otherwise the client is added to the head.
+  defp put_client(html, attributes) do
+    if String.contains?(html, @client) do
+      String.replace(html, @src, @src <> attributes, global: false)
+    else
+      insert(html, ~s(<script type="module" #{@src}#{attributes}></script>))
+    end
+  end
+
+  defp morph_attribute(false), do: ""
+  defp morph_attribute(true), do: attribute(Document.morph_attribute(), "")
+
+  defp morph_attribute(opts) when is_list(opts),
+    do: attribute(Document.morph_attribute(), Keyword.get(opts, :preserve, ""))
+
+  defp attribute(name, value),
+    do: ~s( #{name}="#{value |> Plug.HTML.html_escape() |> IO.iodata_to_binary()}")
+
+  defp html?(conn) do
+    conn
+    |> Conn.get_resp_header("content-type")
+    |> Enum.any?(&String.starts_with?(&1, "text/html"))
+  end
+
+  defp insert(html, tag) do
+    case :binary.match(html, "</head>") do
+      {position, _length} ->
+        binary_part(html, 0, position) <>
+          tag <> binary_part(html, position, byte_size(html) - position)
+
+      :nomatch ->
+        html
+    end
+  end
+end
diff --git a/lib/volt/dev_server/config.ex b/lib/volt/dev_server/config.ex
index 7dc82e4..50cc62b 100644
--- a/lib/volt/dev_server/config.ex
+++ b/lib/volt/dev_server/config.ex
@@ -15,5 +15,12 @@ defmodule Volt.DevServer.Config do
             module_types: %{},
             define: %{},
             hmr_timeout: 60_000,
+            morph: false,
+            document: nil,
+            session: :default,
+            tables: nil,
+            stylesheet_url: nil,
+            stylesheet_source: nil,
+            session_supervisor: nil,
             watcher_opts: nil
 end
diff --git a/lib/volt/ets.ex b/lib/volt/ets.ex
index 5ee8173..6ac6ffc 100644
--- a/lib/volt/ets.ex
+++ b/lib/volt/ets.ex
@@ -1,6 +1,12 @@
 defmodule Volt.ETS do
   @moduledoc "Small helpers for Volt's named ETS tables."
 
+  @doc "Resolve an owned session table or the legacy table at the API boundary."
+  def session_table(%Volt.Dev.Session.Tables{} = tables, kind, _legacy),
+    do: Map.fetch!(tables, kind)
+
+  def session_table(_session, _kind, legacy), do: legacy
+
   @doc "Create a public named set table optimized for concurrent reads."
   def create_named_set(table) do
     :ets.new(table, [:named_table, :set, :public, read_concurrency: true])
@@ -19,6 +25,12 @@ defmodule Volt.ETS do
     :ok
   end
 
+  @doc "Delete rows keyed by {session, key} for one exact session."
+  def clear_session(table, session) do
+    :ets.select_delete(table, [{{{:"$1", :_}, :_}, [{:"=:=", :"$1", {:const, session}}], [true]}])
+    :ok
+  end
+
   @doc "Remove all rows from an ETS table and return `:ok`."
   def clear(table) do
     :ets.delete_all_objects(table)
diff --git a/lib/volt/format.ex b/lib/volt/format.ex
index e135787..dd90c84 100644
--- a/lib/volt/format.ex
+++ b/lib/volt/format.ex
@@ -4,17 +4,6 @@ defmodule Volt.Format do
   def format_size(bytes) when bytes < 1024, do: "#{bytes} B"
   def format_size(bytes), do: "#{Float.round(bytes / 1024, 1)} KB"
 
-  def file_mtime(path) do
-    case File.stat(path, time: :posix) do
-      {:ok, %{mtime: mtime}} when is_integer(mtime) -> mtime
-      _ -> 0
-    end
-  end
-
-  def content_hash(content) do
-    :crypto.hash(:sha256, content) |> Base.encode16(case: :lower) |> binary_part(0, 8)
-  end
-
   def gzip_size(content) when is_binary(content) do
     :zlib.gzip(content) |> byte_size()
   end
diff --git a/lib/volt/formatter.ex b/lib/volt/formatter.ex
index c57acb9..bd09fb3 100644
--- a/lib/volt/formatter.ex
+++ b/lib/volt/formatter.ex
@@ -17,8 +17,15 @@ defmodule Volt.Formatter do
 
   ## Configuration
 
-  Reads options from `config :volt, :format` or falls back to
-  `.oxfmtrc.json` / `.prettierrc.json`. See the "Formatter & linter configuration" section in the README for details.
+  Set oxfmt options under the `:volt` key of the same file:
+
+      [
+        plugins: [Volt.Formatter],
+        volt: [semi: false, single_quote: true, print_width: 100]
+      ]
+
+  Without that key, options come from `.oxfmtrc.json` / `.prettierrc.json`.
+  See the "Formatting and Linting" guide for details.
   """
 
   @behaviour Mix.Tasks.Format
@@ -31,7 +38,7 @@ defmodule Volt.Formatter do
   @impl true
   def format(contents, opts) do
     filename = opts[:file] || extension_to_filename(opts[:extension]) || "input.ts"
-    format_opts = Volt.JS.Format.load_config()
+    format_opts = Volt.JS.Format.load_config(opts)
 
     OXC.Format.run!(contents, filename, format_opts)
   end
diff --git a/lib/volt/hmr.ex b/lib/volt/hmr.ex
index 5c4d356..d127791 100644
--- a/lib/volt/hmr.ex
+++ b/lib/volt/hmr.ex
@@ -10,8 +10,10 @@ defmodule Volt.HMR do
 
   @doc "Broadcast an HMR message to all connected clients."
   @spec broadcast(:update | :error | :ping | :pong, term()) :: :ok
-  def broadcast(type, payload \\ nil) do
-    Registry.dispatch(Volt.HMR.Registry, :clients, fn entries ->
+  def broadcast(type, payload \\ nil, opts \\ []) do
+    session = Keyword.get(opts, :session, :default)
+
+    Registry.dispatch(Volt.HMR.Registry, Volt.HMR.Channel.key(session), fn entries ->
       for {pid, _} <- entries do
         send(pid, {:volt_hmr, type, payload})
       end
@@ -31,26 +33,65 @@ defmodule Volt.HMR do
     payload = maybe_put(payload, :boundary, Keyword.get(opts, :boundary))
     payload = maybe_put(payload, :timestamp, Keyword.get(opts, :timestamp))
 
-    broadcast(:update, payload)
+    broadcast(:update, payload, opts)
   end
 
   @doc "Broadcast a full page reload request for a changed path."
   @spec full_reload(String.t()) :: :ok
-  def full_reload(path), do: update(path, [:full])
+  def full_reload(path, opts \\ []), do: update(path, [:full], opts)
+
+  @doc """
+  Ask open pages to check whether their server-rendered HTML changed.
+
+  Use this for templates and content, which may affect any page or none. Pages
+  that carry an entity tag reload only when their HTML changed; see
+  `Volt.HMR.Document`. Other pages reload.
+  """
+  @spec document_update(String.t()) :: :ok
+  def document_update(path, opts \\ []), do: update(path, [:document], opts)
 
   @doc "Broadcast a style-only update for a changed stylesheet path."
   @spec style_update(String.t()) :: :ok
-  def style_update(path), do: update(path, [:style])
+  def style_update(path, opts \\ []), do: update(path, [:style], opts)
+
+  @doc """
+  Report the errors for a source path and show them in connected browsers.
+
+  `reason` may be `OXC.Diagnostic` maps, messages, exceptions, or any other term;
+  see `Volt.Dev.Error.entries/2`. The errors stay current until `clear_error/2`,
+  so browsers that connect later show them too.
+
+  ## Options
 
-  @doc "Broadcast an error payload for a source path."
-  @spec error(String.t(), term()) :: :ok
-  def error(path, reason), do: broadcast(:error, %{path: path, reason: reason})
+    * `:session` — the development session. Default: `:default`
+    * `:title` — the overlay heading for these errors, such as `"Render error"`.
+      Default: `"Build error"`
+  """
+  @spec error(String.t(), term(), keyword()) :: :ok
+  def error(path, reason, opts \\ []) do
+    session = Keyword.get(opts, :session, :default)
+    entries = Volt.Dev.Error.entries(reason, file: path, title: Keyword.get(opts, :title))
+    Volt.HMR.Errors.put(session, path, entries)
+    broadcast_errors(session)
+  end
+
+  @doc "Clear the errors reported for a source path, hiding the overlay when none remain."
+  @spec clear_error(String.t(), keyword()) :: :ok
+  def clear_error(path, opts \\ []) do
+    session = Keyword.get(opts, :session, :default)
+    if Volt.HMR.Errors.delete(session, path), do: broadcast_errors(session), else: :ok
+  end
+
+  defp broadcast_errors(session) do
+    broadcast(:error, %{errors: Volt.HMR.Errors.list(session)}, session: session)
+  end
 
   @doc "Invalidate Volt's dev compilation state for a source file without broadcasting."
   @spec invalidate_file(String.t()) :: :ok
-  def invalidate_file(path) do
-    Volt.Cache.evict_file(path)
-    Volt.HMR.ModuleGraph.invalidate_file(path)
+  def invalidate_file(path, opts \\ []) do
+    session = Keyword.get(opts, :session, :default)
+    Volt.Cache.evict_file(path, session)
+    Volt.HMR.ModuleGraph.invalidate_file(path, System.system_time(:millisecond), session)
     :ok
   end
 
diff --git a/lib/volt/hmr/boundary.ex b/lib/volt/hmr/boundary.ex
index 40b09a9..410b865 100644
--- a/lib/volt/hmr/boundary.ex
+++ b/lib/volt/hmr/boundary.ex
@@ -33,18 +33,18 @@ defmodule Volt.HMR.Boundary do
   """
   @spec find_boundary(String.t(), (String.t() -> String.t() | nil)) ::
           {:ok, String.t()} | :full_reload
-  def find_boundary(changed_path, read_source) do
+  def find_boundary(changed_path, read_source, session \\ :default) do
     source = read_source.(changed_path)
 
     cond do
       source && self_accepting?(source) ->
         {:ok, changed_path}
 
-      graph_boundary = find_graph_boundary(changed_path, read_source) ->
+      graph_boundary = find_graph_boundary(changed_path, read_source, session) ->
         graph_boundary
 
       true ->
-        walk_up(changed_path, changed_path, read_source, MapSet.new([changed_path]))
+        walk_up(changed_path, changed_path, read_source, MapSet.new([changed_path]), session)
     end
   end
 
@@ -127,9 +127,9 @@ defmodule Volt.HMR.Boundary do
     resolved == changed_path or Path.rootname(resolved) == Path.rootname(changed_path)
   end
 
-  defp find_graph_boundary(changed_path, read_source) do
+  defp find_graph_boundary(changed_path, read_source, session) do
     changed_path
-    |> Volt.HMR.ModuleGraph.get_by_file()
+    |> Volt.HMR.ModuleGraph.get_by_file(session)
     |> case do
       [] ->
         nil
@@ -139,12 +139,13 @@ defmodule Volt.HMR.Boundary do
           nodes,
           changed_path,
           read_source,
-          MapSet.new(Enum.map(nodes, & &1.id))
+          MapSet.new(Enum.map(nodes, & &1.id)),
+          session
         )
     end
   end
 
-  defp find_graph_boundary_in_nodes(nodes, changed_path, read_source, visited) do
+  defp find_graph_boundary_in_nodes(nodes, changed_path, read_source, visited, session) do
     Enum.find_value(nodes, :full_reload, fn node ->
       cond do
         graph_accepts_update?(node, changed_path, read_source) ->
@@ -155,12 +156,13 @@ defmodule Volt.HMR.Boundary do
 
         true ->
           node.importers
-          |> Enum.flat_map(&List.wrap(Volt.HMR.ModuleGraph.get_by_id(&1)))
+          |> Enum.flat_map(&List.wrap(Volt.HMR.ModuleGraph.get_by_id(&1, session)))
           |> Enum.reject(&MapSet.member?(visited, &1.id))
           |> find_graph_boundary_in_nodes(
             changed_path,
             read_source,
-            MapSet.union(visited, node.importers)
+            MapSet.union(visited, node.importers),
+            session
           )
           |> case do
             :full_reload -> nil
@@ -180,47 +182,50 @@ defmodule Volt.HMR.Boundary do
     end
   end
 
-  defp walk_up(path, changed_path, read_source, visited) do
-    case find_importers(path) do
+  defp walk_up(path, changed_path, read_source, visited, session) do
+    case find_importers(path, session) do
       [] -> :full_reload
-      parents -> find_boundary_in_parents(parents, changed_path, read_source, visited)
+      parents -> find_boundary_in_parents(parents, changed_path, read_source, visited, session)
     end
   end
 
-  defp find_boundary_in_parents(parents, changed_path, read_source, visited) do
+  defp find_boundary_in_parents(parents, changed_path, read_source, visited, session) do
     Enum.find_value(parents, :full_reload, fn parent ->
       if MapSet.member?(visited, parent) do
         nil
       else
-        visit_parent(parent, changed_path, read_source, MapSet.put(visited, parent))
+        visit_parent(parent, changed_path, read_source, MapSet.put(visited, parent), session)
       end
     end)
   end
 
-  defp visit_parent(parent, changed_path, read_source, visited) do
+  defp visit_parent(parent, changed_path, read_source, visited, session) do
     source = read_source.(parent)
 
     if source != nil and
          (self_accepting?(source) or dependency_accepting?(source, parent, changed_path)) do
       {:ok, parent}
     else
-      case walk_up(parent, changed_path, read_source, visited) do
+      case walk_up(parent, changed_path, read_source, visited, session) do
         {:ok, _} = found -> found
         :full_reload -> nil
       end
     end
   end
 
-  defp find_importers(path) do
+  defp find_importers(path, session) do
     basename = Path.basename(path)
     rootname = Path.rootname(basename)
 
-    Volt.HMR.ImportGraph.dependents_matching(fn specifier ->
-      spec_base = specifier |> String.split("/") |> List.last()
+    Volt.HMR.ImportGraph.dependents_matching(
+      fn specifier ->
+        spec_base = specifier |> String.split("/") |> List.last()
 
-      spec_base == basename or
-        spec_base == rootname or
-        Path.rootname(spec_base) == rootname
-    end)
+        spec_base == basename or
+          spec_base == rootname or
+          Path.rootname(spec_base) == rootname
+      end,
+      session
+    )
   end
 end
diff --git a/lib/volt/hmr/channel.ex b/lib/volt/hmr/channel.ex
new file mode 100644
index 0000000..63efceb
--- /dev/null
+++ b/lib/volt/hmr/channel.ex
@@ -0,0 +1,6 @@
+defmodule Volt.HMR.Channel do
+  @moduledoc "Registry channel identity for development-session subscribers."
+
+  def key(:default), do: :clients
+  def key(session), do: {:clients, session}
+end
diff --git a/lib/volt/hmr/document.ex b/lib/volt/hmr/document.ex
new file mode 100644
index 0000000..b0a0b92
--- /dev/null
+++ b/lib/volt/hmr/document.ex
@@ -0,0 +1,183 @@
+defmodule Volt.HMR.Document do
+  @moduledoc """
+  Lets an open page ask whether its server-rendered HTML is still current.
+
+  A change to a template or content file may affect any page, or none. Rather
+  than reloading every open page, Volt's dev client revalidates the page it is
+  on: it requests the page again with the entity tag of the HTML it was served
+  and reloads only when the server answers with something other than
+  `304 Not Modified`.
+
+  `Volt.DevServer` does this for every successful HTML response that passes
+  through it, whether it adds the dev client or the page already loads it with
+  `<script type="module" src="/@volt/client.js">`. A server that sends HTML
+  without going through `Volt.DevServer` takes part by:
+
+    1. computing `etag/1` of the rendered HTML;
+    2. answering `304` with an empty body when `fresh?/2` is true;
+    3. otherwise sending the tag in the `etag` response header and in the
+       `data-volt-etag` attribute of the client `<script>`.
+
+  Pages without the attribute reload on every document update.
+  """
+
+  @attribute "data-volt-etag"
+
+  @doc "The attribute of the client `<script>` that holds the page's entity tag."
+  @spec attribute() :: String.t()
+  def attribute, do: @attribute
+
+  @morph_attribute "data-volt-morph"
+
+  @doc """
+  The attribute of the client `<script>` that lets the client patch the page in
+  place instead of reloading it. Its value is a selector for elements that
+  client code owns, or empty.
+  """
+  @spec morph_attribute() :: String.t()
+  def morph_attribute, do: @morph_attribute
+
+  @doc "Compute the entity tag of rendered HTML."
+  @spec etag(iodata()) :: String.t()
+  def etag(html) do
+    digest =
+      :crypto.hash(:sha256, html) |> Base.url_encode64(padding: false) |> binary_part(0, 22)
+
+    ~s("#{digest}")
+  end
+
+  @doc "Return whether the request already holds the HTML that `etag` identifies."
+  @spec fresh?(Plug.Conn.t(), String.t()) :: boolean()
+  def fresh?(conn, etag), do: etag in Plug.Conn.get_req_header(conn, "if-none-match")
+
+  @typedoc """
+  A preserved element whose server-rendered attributes changed: its position
+  among the elements matching the preserve selector, and its new attributes.
+  """
+  @type owned_change :: %{index: non_neg_integer(), attributes: %{String.t() => String.t()}}
+
+  @typedoc "Attributes the server set or changed on an element, and those it removed."
+  @type attribute_changes :: %{set: %{String.t() => String.t()}, remove: [String.t()]}
+
+  @typedoc """
+  What the server changed outside the body's contents, which are patched from
+  the new HTML itself:
+
+    * `:owned` — preserved elements whose attributes changed
+    * `:root` — attribute changes on `"html"` and `"body"`, for those that have any
+    * `:head` — head elements, as HTML, that are gone and that are new. Scripts,
+      stylesheets and the title are not among them.
+  """
+  @type patch :: %{
+          owned: [owned_change()],
+          root: %{String.t() => attribute_changes()},
+          head: %{remove: [String.t()], add: [String.t()]}
+        }
+
+  @doc """
+  Decide how a page gets from one server render to the next.
+
+  Both arguments are HTML the server rendered, so the comparison sees only what
+  the server changed, never what scripts did to the page since. An attribute a
+  script set on `<html>` is in neither render and is left alone.
+
+  Returns `:reload` when patching cannot apply the change: the scripts the page
+  runs or its stylesheets differ, or elements matching `preserve` were added or
+  removed. Otherwise returns `{:patch, patch}`.
+  """
+  @spec changes(String.t(), String.t(), String.t() | nil) :: :reload | {:patch, patch()}
+  def changes(previous, next, preserve) do
+    previous = Floki.parse_document!(previous)
+    next = Floki.parse_document!(next)
+
+    with true <- scripts(previous) == scripts(next),
+         true <- stylesheets(previous) == stylesheets(next),
+         {:ok, owned} <- owned_changes(preserved(previous, preserve), preserved(next, preserve)) do
+      {:patch,
+       %{
+         owned: owned,
+         root: root_changes(previous, next),
+         head: head_changes(head_elements(previous), head_elements(next))
+       }}
+    else
+      _cannot_patch -> :reload
+    end
+  end
+
+  defp root_changes(previous, next) do
+    for tag <- ["html", "body"],
+        changes = attribute_changes(root_attributes(previous, tag), root_attributes(next, tag)),
+        changes != %{set: %{}, remove: []},
+        into: %{},
+        do: {tag, changes}
+  end
+
+  defp root_attributes(document, tag) do
+    case Floki.find(document, tag) do
+      [{^tag, attributes, _children} | _] -> Map.new(attributes)
+      [] -> %{}
+    end
+  end
+
+  defp attribute_changes(previous, next) do
+    %{
+      set: Map.reject(next, fn {name, value} -> Map.get(previous, name) == value end),
+      remove: Map.keys(previous) -- Map.keys(next)
+    }
+  end
+
+  # Head elements that can be replaced without side effects: metadata and links
+  # other than stylesheets.
+  defp head_elements(document) do
+    for {"head", _attributes, children} <- Floki.find(document, "head"),
+        {tag, attributes, _children} = element <- children,
+        tag not in ["script", "style", "title"],
+        not (tag == "link" and attribute(attributes, "rel") == "stylesheet"),
+        do: Floki.raw_html(element)
+  end
+
+  defp head_changes(previous, next), do: %{remove: previous -- next, add: next -- previous}
+
+  # Scripts the browser runs. Data blocks such as JSON are content and are patched.
+  defp scripts(document) do
+    for {"script", attributes, children} <- Floki.find(document, "script"),
+        type = attribute(attributes, "type"),
+        type in ["", "module", "text/javascript"],
+        do: {type, attribute(attributes, "src"), Floki.raw_html(children)}
+  end
+
+  defp stylesheets(document) do
+    links =
+      for {"link", attributes, _children} <- Floki.find(document, "link[rel=stylesheet]"),
+          do: attribute(attributes, "href")
+
+    styles = for {"style", _attributes, children} <- Floki.find(document, "style"), do: children
+    {links, styles}
+  end
+
+  defp preserved(_document, preserve) when preserve in [nil, ""], do: []
+
+  defp preserved(document, preserve) do
+    for {_tag, attributes, _children} <- Floki.find(document, preserve), do: Map.new(attributes)
+  end
+
+  defp owned_changes(previous, next) do
+    if length(previous) == length(next) do
+      owned =
+        for {{before, now}, index} <- Enum.with_index(Enum.zip(previous, next)),
+            before != now,
+            do: %{index: index, attributes: now}
+
+      {:ok, owned}
+    else
+      :error
+    end
+  end
+
+  defp attribute(attributes, name) do
+    case List.keyfind(attributes, name, 0) do
+      {^name, value} -> value
+      nil -> ""
+    end
+  end
+end
diff --git a/lib/volt/hmr/documents.ex b/lib/volt/hmr/documents.ex
new file mode 100644
index 0000000..d3a2bc5
--- /dev/null
+++ b/lib/volt/hmr/documents.ex
@@ -0,0 +1,31 @@
+defmodule Volt.HMR.Documents do
+  @moduledoc false
+  # The HTML recently served for pages, per session and entity tag, so the
+  # websocket process of a page that connects can start from the HTML the page
+  # was served without rendering it again.
+
+  @table :volt_hmr_documents
+
+  # Pages that never connect, such as requests from other tools, leave their
+  # HTML behind. A session keeps at most this many before starting over.
+  @limit 64
+
+  def create_table, do: Volt.ETS.create_named_set(@table)
+
+  def put(session, etag, html) do
+    if count(session) >= @limit, do: clear_session(session)
+    Volt.ETS.put(@table, {{session, etag}, html})
+  end
+
+  @spec fetch(term(), String.t()) :: {:ok, String.t()} | :error
+  def fetch(session, etag) do
+    case :ets.lookup(@table, {session, etag}) do
+      [{_key, html}] -> {:ok, html}
+      [] -> :error
+    end
+  end
+
+  def clear_session(session), do: Volt.ETS.clear_session(@table, session)
+
+  defp count(session), do: :ets.select_count(@table, [{{{session, :_}, :_}, [], [true]}])
+end
diff --git a/lib/volt/hmr/errors.ex b/lib/volt/hmr/errors.ex
new file mode 100644
index 0000000..e15c547
--- /dev/null
+++ b/lib/volt/hmr/errors.ex
@@ -0,0 +1,23 @@
+defmodule Volt.HMR.Errors do
+  @moduledoc false
+  # Current development errors per session and source path, so browsers that
+  # connect after a failure still show the overlay.
+
+  @table :volt_hmr_errors
+
+  def create_table, do: Volt.ETS.create_named_set(@table)
+
+  def put(session, path, entries), do: Volt.ETS.put(@table, {{session, path}, entries})
+
+  @doc "Remove the errors for a path and return whether there were any."
+  def delete(session, path), do: :ets.take(@table, {session, path}) != []
+
+  def list(session) do
+    @table
+    |> :ets.match_object({{session, :_}, :_})
+    |> Enum.sort()
+    |> Enum.flat_map(fn {_key, entries} -> entries end)
+  end
+
+  def clear_session(session), do: Volt.ETS.clear_session(@table, session)
+end
diff --git a/lib/volt/hmr/glob_graph.ex b/lib/volt/hmr/glob_graph.ex
index d7a5a96..baa6675 100644
--- a/lib/volt/hmr/glob_graph.ex
+++ b/lib/volt/hmr/glob_graph.ex
@@ -3,34 +3,44 @@ defmodule Volt.HMR.GlobGraph do
 
   @table :volt_hmr_glob_graph
 
+  defp table(session), do: Volt.ETS.session_table(session, :globs, @table)
+
   @doc "Create the glob graph ETS table."
   def create_table, do: Volt.ETS.create_named_set(@table)
 
   @doc "Store glob patterns owned by an importer."
-  def update(importer, globs), do: Volt.ETS.put(@table, {importer, globs})
+  def update(importer, globs, session \\ :default),
+    do: Volt.ETS.put(table(session), {{session, importer}, globs})
 
   @doc "Extract and store `import.meta.glob()` patterns from source."
-  def update_from_source(path, source) do
+  def update_from_source(path, source, session \\ :default) do
     globs =
       source
       |> Volt.JS.Transforms.GlobImports.patterns(Path.basename(path))
       |> Enum.map(&expand_glob_pattern(&1, Path.dirname(path)))
 
-    update(path, globs)
+    update(path, globs, session)
   end
 
   @doc "Find all files with an `import.meta.glob()` pattern matching `path`."
-  def dependents(path) do
+  def dependents(path, session \\ :default) do
     :ets.foldl(
-      fn {importer, globs}, acc ->
-        if glob_match?(globs, path), do: [importer | acc], else: acc
+      fn
+        {{^session, importer}, globs}, acc ->
+          if glob_match?(globs, path), do: [importer | acc], else: acc
+
+        _, acc ->
+          acc
       end,
       [],
-      @table
+      table(session)
     )
   end
 
-  def remove(path), do: Volt.ETS.delete(@table, path)
+  def remove(path, session \\ :default), do: Volt.ETS.delete(table(session), {session, path})
+
+  @doc "Remove glob ownership for one session."
+  def clear_session(session), do: Volt.ETS.clear_session(table(session), session)
 
   def clear, do: Volt.ETS.clear(@table)
 
diff --git a/lib/volt/hmr/import_graph.ex b/lib/volt/hmr/import_graph.ex
index 08a7432..7a15590 100644
--- a/lib/volt/hmr/import_graph.ex
+++ b/lib/volt/hmr/import_graph.ex
@@ -9,30 +9,34 @@ defmodule Volt.HMR.ImportGraph do
 
   @table :volt_hmr_import_graph
 
+  defp table(session), do: Volt.ETS.session_table(session, :imports, @table)
+
   @doc "Create the import graph ETS table. Called once from Application.start/2."
   @spec create_table :: :ok
   def create_table, do: Volt.ETS.create_named_set(@table)
 
   @doc "Update the imports for a file path."
   @spec update(String.t(), [String.t()]) :: :ok
-  def update(path, imports), do: Volt.ETS.put(@table, {path, imports})
+  def update(path, imports, session \\ :default) do
+    Volt.ETS.put(table(session), {{session, path}, Enum.uniq(imports)})
+  end
 
   @doc "Update imports from compiled code."
   @spec update_from_compiled(String.t(), String.t()) :: :ok
-  def update_from_compiled(path, compiled_code) do
+  def update_from_compiled(path, compiled_code, session \\ :default) do
     imports =
       case OXC.select(compiled_code, Path.basename(path), :import_specifiers) do
         {:ok, imports} -> imports
         _ -> []
       end
 
-    update(path, imports)
+    update(path, imports, session)
   end
 
   @doc "Get the imports for a file path."
   @spec imports_of(String.t()) :: [String.t()]
-  def imports_of(path) do
-    case :ets.lookup(@table, path) do
+  def imports_of(path, session \\ :default) do
+    case :ets.lookup(table(session), {session, path}) do
       [{_, imports}] -> imports
       [] -> []
     end
@@ -44,14 +48,8 @@ defmodule Volt.HMR.ImportGraph do
   Used by fallback HMR boundary lookup to propagate changes upward through raw imports.
   """
   @spec dependents(String.t()) :: [String.t()]
-  def dependents(specifier) do
-    :ets.foldl(
-      fn {path, imports}, acc ->
-        if specifier in imports, do: [path | acc], else: acc
-      end,
-      [],
-      @table
-    )
+  def dependents(specifier, session \\ :default) do
+    dependents_matching(&(&1 == specifier), session)
   end
 
   @doc """
@@ -61,21 +59,28 @@ defmodule Volt.HMR.ImportGraph do
   if it matches the file being searched for.
   """
   @spec dependents_matching((String.t() -> boolean())) :: [String.t()]
-  def dependents_matching(predicate) do
+  def dependents_matching(predicate, session \\ :default) do
     :ets.foldl(
-      fn {path, imports}, acc ->
-        if Enum.any?(imports, predicate), do: [path | acc], else: acc
+      fn
+        {{^session, path}, imports}, acc ->
+          if Enum.any?(imports, predicate), do: [path | acc], else: acc
+
+        _, acc ->
+          acc
       end,
       [],
-      @table
+      table(session)
     )
   end
 
   @doc "Remove a file from the graph."
   @spec remove(String.t()) :: :ok
-  def remove(path), do: Volt.ETS.delete(@table, path)
+  def remove(path, session \\ :default), do: Volt.ETS.delete(table(session), {session, path})
 
   @doc "Clear the entire graph."
   @spec clear :: :ok
   def clear, do: Volt.ETS.clear(@table)
+
+  @doc "Clear raw import edges for one session."
+  def clear_session(session), do: Volt.ETS.clear_session(table(session), session)
 end
diff --git a/lib/volt/hmr/message.ex b/lib/volt/hmr/message.ex
index b2aecc7..4ea0ecf 100644
--- a/lib/volt/hmr/message.ex
+++ b/lib/volt/hmr/message.ex
@@ -8,7 +8,9 @@ defmodule Volt.HMR.Message do
   ## Wire types
 
     * `update` — an HMR update payload (`path`, `changes`, optional `boundary`, `timestamp`)
-    * `error` — a build/runtime error to surface in the overlay
+    * `error` — the current build errors (`errors`, as `t:Volt.Dev.Error.entry/0` maps);
+      an empty list hides the overlay
+    * `page` — sent by the browser client once connected: the `path` it shows and the `etag` of its HTML
     * `ping` — heartbeat sent by the browser client
     * `pong` — heartbeat reply from the server
 
@@ -17,7 +19,7 @@ defmodule Volt.HMR.Message do
   use JSONCodec
 
   @type t :: %__MODULE__{
-          type: :update | :error | :ping | :pong,
+          type: :update | :error | :page | :ping | :pong,
           payload: term() | nil
         }
 
diff --git a/lib/volt/hmr/module_graph.ex b/lib/volt/hmr/module_graph.ex
index fed725d..fbadad8 100644
--- a/lib/volt/hmr/module_graph.ex
+++ b/lib/volt/hmr/module_graph.ex
@@ -1,18 +1,12 @@
 defmodule Volt.HMR.ModuleGraph do
-  @moduledoc """
-  ETS-backed dev-server module graph.
+  @moduledoc "Session-scoped module graph indexed by URL, resolved identity, and source file."
 
-  The graph is keyed by served URL, resolved module id, and source file. It is
-  the primary source for HMR boundary lookup: served modules record their
-  resolved imports, importers, query variants, and whether the module accepts
-  itself with `import.meta.hot.accept()`.
-  """
+  alias Volt.ETS
 
   @table :volt_hmr_module_graph
 
   defmodule Node do
-    @moduledoc "A dev-server module graph node."
-
+    @moduledoc "A served browser module."
     defstruct url: nil,
               id: nil,
               file: nil,
@@ -23,134 +17,120 @@ defmodule Volt.HMR.ModuleGraph do
               last_invalidated_at: nil
   end
 
-  @doc "Create the module graph ETS table."
-  def create_table do
-    :ets.new(@table, [:named_table, :set, :public, read_concurrency: true])
-    :ok
-  end
+  defp table(session), do: Volt.ETS.session_table(session, :modules, @table)
+
+  def create_table, do: ETS.create_named_set(@table)
 
-  @doc "Upsert a module and update importer links for its resolved imports."
   def update_module(url, id, file, imports, opts \\ []) do
-    old_node = get_by_id(id)
-    remove_old_importer_links(old_node, id)
+    session = Keyword.get(opts, :session, :default)
+    old = get_by_id(id, session)
+    unlink_imports(old, session)
+    if old && old.url != url, do: ETS.delete(table(session), {session, {:url, old.url}})
+    if old && old.file != file, do: unlink_file(old, session)
+
+    importers =
+      for node <- nodes(session),
+          MapSet.member?(node.imports, id),
+          into: MapSet.new(),
+          do: node.id
 
     node = %Node{
       url: url,
       id: id,
       file: file,
-      type: Keyword.get(opts, :type, module_type(url)),
       imports: MapSet.new(imports),
-      importers: existing_importers(id, old_node),
+      importers: importers,
+      type: Keyword.get(opts, :type, module_type(url)),
       self_accepting: Keyword.get(opts, :self_accepting, false)
     }
 
-    put_node(node)
-    Enum.each(node.imports, &put_importer_link(&1, id))
+    put_node(node, session)
+
+    Enum.each(node.imports, fn imported_id ->
+      if imported = get_by_id(imported_id, session) do
+        put_node(%{imported | importers: MapSet.put(imported.importers, id)}, session)
+      end
+    end)
+
     :ok
   end
 
-  def get_by_url(url), do: lookup({:url, url})
-  def get_by_id(id), do: lookup({:id, id})
-
-  def get_by_file(file) do
-    case :ets.lookup(@table, {:file, file}) do
-      [{_, ids}] -> Enum.flat_map(ids, &List.wrap(get_by_id(&1)))
-      [] -> []
+  def get_by_url(url, session \\ :default) do
+    case lookup({:url, url}, session) do
+      nil -> nil
+      id -> get_by_id(id, session)
     end
   end
 
-  @doc "Mark every graph node for a file as invalidated and return affected nodes."
-  def invalidate_file(file, timestamp \\ System.system_time(:millisecond)) do
-    nodes = get_by_file(file)
+  def get_by_id(id, session \\ :default), do: lookup({:id, id}, session)
 
-    Enum.each(nodes, fn node ->
-      put_node(%{node | last_invalidated_at: timestamp})
-    end)
+  def get_by_file(file, session \\ :default) do
+    (lookup({:file, file}, session) || MapSet.new())
+    |> Enum.flat_map(&List.wrap(get_by_id(&1, session)))
+  end
 
+  def invalidate_file(file, timestamp \\ System.system_time(:millisecond), session \\ :default) do
+    nodes = get_by_file(file, session)
+    Enum.each(nodes, &put_node(%{&1 | last_invalidated_at: timestamp}, session))
     nodes
   end
 
-  @doc "Remove all nodes for a file and unlink them from importers/imports."
-  def remove_file(file) do
-    file
-    |> get_by_file()
-    |> Enum.each(&remove_node/1)
+  def remove_file(file, session \\ :default) do
+    Enum.each(get_by_file(file, session), fn node ->
+      unlink_imports(node, session)
 
-    :ets.delete(@table, {:file, file})
-    :ok
-  end
+      Enum.each(node.importers, fn id ->
+        if importer = get_by_id(id, session) do
+          put_node(%{importer | imports: MapSet.delete(importer.imports, node.id)}, session)
+        end
+      end)
 
-  def clear do
-    :ets.delete_all_objects(@table)
-    :ok
-  end
+      ETS.delete(table(session), {session, {:url, node.url}})
+      ETS.delete(table(session), {session, {:id, node.id}})
+    end)
 
-  defp put_node(node) do
-    :ets.insert(@table, {{:url, node.url}, node.id})
-    :ets.insert(@table, {{:id, node.id}, node})
-    :ets.insert(@table, {{:file, node.file}, file_ids(node.file, node.id)})
+    ETS.delete(table(session), {session, {:file, file}})
   end
 
-  defp existing_importers(id, nil), do: existing_importers(id, %Node{})
-
-  defp existing_importers(id, old_node) do
-    @table
-    |> :ets.tab2list()
-    |> Enum.reduce(old_node.importers, fn
-      {{:id, importer_id}, %Node{imports: imports}}, acc when importer_id != id ->
-        if MapSet.member?(imports, id), do: MapSet.put(acc, importer_id), else: acc
-
-      _entry, acc ->
-        acc
-    end)
+  def clear, do: ETS.clear(@table)
+  def clear_session(session), do: ETS.clear_session(table(session), session)
+
+  defp nodes(session) do
+    :ets.foldl(
+      fn
+        {{^session, {:id, _}}, node}, acc -> [node | acc]
+        _, acc -> acc
+      end,
+      [],
+      table(session)
+    )
   end
 
-  defp put_importer_link(import_id, importer_id) do
-    case get_by_id(import_id) do
-      nil -> :ok
-      node -> put_node(%{node | importers: MapSet.put(node.importers, importer_id)})
-    end
+  defp put_node(node, session) do
+    ids = lookup({:file, node.file}, session) || MapSet.new()
+    ETS.put(table(session), {{session, {:url, node.url}}, node.id})
+    ETS.put(table(session), {{session, {:id, node.id}}, node})
+    ETS.put(table(session), {{session, {:file, node.file}}, MapSet.put(ids, node.id)})
   end
 
-  defp remove_old_importer_links(nil, _id), do: :ok
-
-  defp remove_old_importer_links(node, id) do
-    Enum.each(node.imports, fn import_id ->
-      case get_by_id(import_id) do
-        nil -> :ok
-        imported -> put_node(%{imported | importers: MapSet.delete(imported.importers, id)})
-      end
-    end)
+  defp unlink_file(node, session) do
+    ids = lookup({:file, node.file}, session) || MapSet.new()
+    ETS.put(table(session), {{session, {:file, node.file}}, MapSet.delete(ids, node.id)})
   end
 
-  defp remove_node(node) do
-    remove_old_importer_links(node, node.id)
+  defp unlink_imports(nil, _session), do: :ok
 
-    Enum.each(node.importers, fn importer_id ->
-      case get_by_id(importer_id) do
-        nil -> :ok
-        importer -> put_node(%{importer | imports: MapSet.delete(importer.imports, node.id)})
+  defp unlink_imports(node, session) do
+    Enum.each(node.imports, fn id ->
+      if imported = get_by_id(id, session) do
+        put_node(%{imported | importers: MapSet.delete(imported.importers, node.id)}, session)
       end
     end)
-
-    :ets.delete(@table, {:url, node.url})
-    :ets.delete(@table, {:id, node.id})
-  end
-
-  defp file_ids(file, id) do
-    existing =
-      case :ets.lookup(@table, {:file, file}) do
-        [{_, ids}] -> ids
-        [] -> MapSet.new()
-      end
-
-    MapSet.put(existing, id)
   end
 
-  defp lookup(key) do
-    case :ets.lookup(@table, key) do
-      [{_, %Node{} = node}] -> node
-      [{_, id}] when elem(key, 0) == :url -> get_by_id(id)
+  defp lookup(key, session) do
+    case :ets.lookup(table(session), {session, key}) do
+      [{_, value}] -> value
       [] -> nil
     end
   end
diff --git a/lib/volt/hmr/socket.ex b/lib/volt/hmr/socket.ex
index 34433c4..f84feee 100644
--- a/lib/volt/hmr/socket.ex
+++ b/lib/volt/hmr/socket.ex
@@ -8,12 +8,43 @@ defmodule Volt.HMR.Socket do
   @behaviour WebSock
   require Logger
 
+  alias Volt.HMR.Document
+
+  # One socket process lives as long as one open page. When the server can
+  # render documents and pages are patched in place, the process keeps the HTML
+  # the server last rendered for its page. On a document update it renders the
+  # page again and compares the two renders, so each page hears only what
+  # applies to it: nothing, a reload, or a patch.
+  defstruct session: :default, document: nil, morph: false, path: nil, html: nil
+
   @impl true
-  def init(_args) do
-    Registry.register(Volt.HMR.Registry, :clients, nil)
-    {:ok, %{}}
+  def init(nil), do: init([])
+
+  def init(args) do
+    session = Keyword.get(args, :session, :default)
+    Registry.register(Volt.HMR.Registry, Volt.HMR.Channel.key(session), nil)
+
+    morph = Keyword.get(args, :morph, false)
+
+    state = %__MODULE__{
+      session: session,
+      document: document(Keyword.get(args, :document), morph),
+      morph: morph
+    }
+
+    case Volt.HMR.Errors.list(session) do
+      [] -> {:ok, state}
+      errors -> push(%Volt.HMR.Message{type: :error, payload: %{errors: errors}}, state)
+    end
   end
 
+  # Without patching, a changed page reloads and fetches its own HTML.
+  defp document(_document, false), do: nil
+  defp document(document, _morph), do: document
+
+  defp preserve(morph) when is_list(morph), do: Keyword.get(morph, :preserve)
+  defp preserve(_morph), do: nil
+
   # Heartbeat: the browser client sends a `{"type":"ping"}` JSON message
   # every few seconds to keep Bandit's websocket `read_timeout` from closing
   # an otherwise idle connection. We reply with `{"type":"pong"}` so the
@@ -25,6 +56,9 @@ defmodule Volt.HMR.Socket do
       {:ok, %Volt.HMR.Message{type: :ping}} ->
         push(%Volt.HMR.Message{type: :pong}, state)
 
+      {:ok, %Volt.HMR.Message{type: :page, payload: payload}} ->
+        {:ok, open_page(state, payload)}
+
       {:ok, %Volt.HMR.Message{type: type} = message} ->
         Logger.debug("[Volt.HMR] Received: #{inspect(type)} #{inspect(message.payload)}")
         {:ok, state}
@@ -35,7 +69,36 @@ defmodule Volt.HMR.Socket do
     end
   end
 
+  # The page says where it is and which HTML it was served. That HTML was kept
+  # when it was sent. If it is gone, the page is rendered again, and the render
+  # is used only if it is the HTML the page has; otherwise the page falls back
+  # to revalidating itself.
+  defp open_page(%__MODULE__{document: document} = state, %{"path" => path, "etag" => etag})
+       when not is_nil(document) and is_binary(path) and is_binary(etag) do
+    %{state | path: path, html: served_html(state, path, etag)}
+  end
+
+  defp open_page(state, _payload), do: state
+
   @impl true
+  def handle_info(
+        {:volt_hmr, :update, %{changes: ["document"]} = payload},
+        %__MODULE__{html: html} = state
+      )
+      when is_binary(html) do
+    case render(state.document, state.path) do
+      {:ok, ^html} ->
+        {:ok, state}
+
+      {:ok, next} ->
+        update_document(Document.changes(html, next, preserve(state.morph)), next, payload, state)
+
+      _error ->
+        # The page revalidates itself and shows what the server answers.
+        push(%Volt.HMR.Message{type: :update, payload: payload}, %{state | html: nil})
+    end
+  end
+
   def handle_info({:volt_hmr, type, payload}, state) do
     push(%Volt.HMR.Message{type: type, payload: payload}, state)
   end
@@ -44,6 +107,34 @@ defmodule Volt.HMR.Socket do
     {:ok, state}
   end
 
+  defp update_document(:reload, _next, payload, state) do
+    payload = %{payload | changes: ["full"]}
+    push(%Volt.HMR.Message{type: :update, payload: payload}, %{state | html: nil})
+  end
+
+  defp update_document({:patch, patch}, next, payload, state) do
+    etag = Document.etag(next)
+
+    # The page gets the HTML a request for it would be answered with.
+    tagged = Volt.DevServer.ClientTag.tag(next, etag, state.morph)
+    payload = payload |> Map.merge(patch) |> Map.merge(%{html: tagged, etag: etag})
+    push(%Volt.HMR.Message{type: :update, payload: payload}, %{state | html: next})
+  end
+
+  defp served_html(state, path, etag) do
+    with :error <- Volt.HMR.Documents.fetch(state.session, etag),
+         {:ok, html} <- render(state.document, path),
+         ^etag <- Document.etag(html) do
+      html
+    else
+      {:ok, html} -> html
+      _other -> nil
+    end
+  end
+
+  defp render({module, function, args}, path), do: apply(module, function, [path | args])
+  defp render(document, path) when is_function(document, 1), do: document.(path)
+
   defp push(%Volt.HMR.Message{} = message, state) do
     case encode(message) do
       {:ok, frame} -> {:push, frame, state}
diff --git a/lib/volt/hmr/style_dependencies.ex b/lib/volt/hmr/style_dependencies.ex
index f5d4c5e..e739c67 100644
--- a/lib/volt/hmr/style_dependencies.ex
+++ b/lib/volt/hmr/style_dependencies.ex
@@ -11,14 +11,14 @@ defmodule Volt.HMR.StyleDependencies do
 
   @doc "Update stylesheet dependency state for a compiled source file."
   @spec update_from_compile(String.t(), String.t(), Volt.Pipeline.Result.t() | map()) :: :ok
-  def update_from_compile(path, source, result) do
+  def update_from_compile(path, source, result, session \\ :default) do
     case dependency_source(path, source, result) do
       nil ->
-        Volt.HMR.StyleGraph.remove(path)
+        Volt.HMR.StyleGraph.remove(path, session)
 
       css ->
         dependencies = Volt.CSS.Dependencies.resolve(css, path)
-        Volt.HMR.StyleGraph.update(path, dependencies)
+        Volt.HMR.StyleGraph.update(path, dependencies, session)
     end
   end
 
diff --git a/lib/volt/hmr/style_graph.ex b/lib/volt/hmr/style_graph.ex
index 91f4dc4..713189c 100644
--- a/lib/volt/hmr/style_graph.ex
+++ b/lib/volt/hmr/style_graph.ex
@@ -10,26 +10,28 @@ defmodule Volt.HMR.StyleGraph do
 
   @table :volt_hmr_style_graph
 
+  defp table(session), do: Volt.ETS.session_table(session, :styles, @table)
+
   @doc "Create the stylesheet graph ETS table. Called once from Application.start/2."
   @spec create_table :: :ok
   def create_table, do: Volt.ETS.create_named_set(@table)
 
   @doc "Update resolved dependencies for a stylesheet source file."
   @spec update(String.t(), [String.t()]) :: :ok
-  def update(path, dependencies) do
-    old_dependencies = dependencies_of(path)
+  def update(path, dependencies, session \\ :default) do
+    old_dependencies = dependencies_of(path, session)
     dependencies = dependencies |> Enum.uniq() |> MapSet.new()
 
     Enum.each(old_dependencies, fn dependency ->
-      dependents = dependency |> dependents_of() |> MapSet.new() |> MapSet.delete(path)
-      put_dependents(dependency, dependents)
+      dependents = dependency |> dependents_of(session) |> MapSet.new() |> MapSet.delete(path)
+      put_dependents(dependency, dependents, session)
     end)
 
-    Volt.ETS.put(@table, {{:dependencies, path}, dependencies})
+    Volt.ETS.put(table(session), {{session, {:dependencies, path}}, dependencies})
 
     Enum.each(dependencies, fn dependency ->
-      dependents = dependency |> dependents_of() |> MapSet.new() |> MapSet.put(path)
-      put_dependents(dependency, dependents)
+      dependents = dependency |> dependents_of(session) |> MapSet.new() |> MapSet.put(path)
+      put_dependents(dependency, dependents, session)
     end)
 
     :ok
@@ -37,18 +39,20 @@ defmodule Volt.HMR.StyleGraph do
 
   @doc "Return direct resolved dependencies for a stylesheet source file."
   @spec dependencies_of(String.t()) :: [String.t()]
-  def dependencies_of(path), do: lookup_set({:dependencies, path})
+  def dependencies_of(path, session \\ :default),
+    do: lookup_set({session, {:dependencies, path}}, session)
 
   @doc "Return all transitive stylesheets that depend on a source file."
   @spec dependents(String.t()) :: [String.t()]
-  def dependents(path), do: dependents(path, MapSet.new([path]))
+  def dependents(path, session \\ :default),
+    do: walk_dependents(path, MapSet.new([path]), session)
 
   @doc "Remove a stylesheet from the graph."
   @spec remove(String.t()) :: :ok
-  def remove(path) do
-    update(path, [])
-    Volt.ETS.delete(@table, {:dependencies, path})
-    Volt.ETS.delete(@table, {:dependents, path})
+  def remove(path, session \\ :default) do
+    update(path, [], session)
+    Volt.ETS.delete(table(session), {session, {:dependencies, path}})
+    Volt.ETS.delete(table(session), {session, {:dependents, path}})
     :ok
   end
 
@@ -56,28 +60,31 @@ defmodule Volt.HMR.StyleGraph do
   @spec clear :: :ok
   def clear, do: Volt.ETS.clear(@table)
 
-  defp dependents(path, seen) do
+  @doc "Clear stylesheet edges belonging to one session."
+  def clear_session(session), do: Volt.ETS.clear_session(table(session), session)
+
+  defp walk_dependents(path, seen, session) do
     path
-    |> dependents_of()
+    |> dependents_of(session)
     |> Enum.reject(&MapSet.member?(seen, &1))
     |> Enum.flat_map(fn stylesheet ->
-      [stylesheet | dependents(stylesheet, MapSet.put(seen, stylesheet))]
+      [stylesheet | walk_dependents(stylesheet, MapSet.put(seen, stylesheet), session)]
     end)
     |> Enum.uniq()
   end
 
-  defp dependents_of(path), do: lookup_set({:dependents, path})
+  defp dependents_of(path, session), do: lookup_set({session, {:dependents, path}}, session)
 
-  defp put_dependents(path, dependents) do
+  defp put_dependents(path, dependents, session) do
     if MapSet.size(dependents) == 0 do
-      Volt.ETS.delete(@table, {:dependents, path})
+      Volt.ETS.delete(table(session), {session, {:dependents, path}})
     else
-      Volt.ETS.put(@table, {{:dependents, path}, dependents})
+      Volt.ETS.put(table(session), {{session, {:dependents, path}}, dependents})
     end
   end
 
-  defp lookup_set(key) do
-    case :ets.lookup(@table, key) do
+  defp lookup_set(key, session) do
+    case :ets.lookup(table(session), key) do
       [{_, set}] -> MapSet.to_list(set)
       [] -> []
     end
diff --git a/lib/volt/js/check.ex b/lib/volt/js/check.ex
index 81c91f2..2fc14d8 100644
--- a/lib/volt/js/check.ex
+++ b/lib/volt/js/check.ex
@@ -27,112 +27,145 @@ defmodule Volt.JS.Check do
 
   def lint(files, opts \\ []) do
     config = Application.get_env(:volt, :lint, [])
-    rules = Keyword.get(config, :rules, %{})
+    lint_config = Volt.JS.Lint.Config.new(config, Volt.Config.build().root)
 
     if opts[:type_aware] do
-      ast_lint(Enum.filter(files, &type_aware_file?/1), config, rules) ++
-        type_aware_lint(files, config, typescript_rules(rules), opts)
+      ast_lint(Enum.filter(files, &type_aware_file?/1), lint_config) ++
+        type_aware_lint(files, config, lint_config, opts)
     else
-      ast_lint(files, config, rules)
+      ast_lint(files, lint_config)
     end
   end
 
   def promote_type_check_diagnostic(%{rule: rule} = diagnostic, opts) do
     if Keyword.get(opts, :type_check, false) and type_check_diagnostic?(rule) do
-      %{diagnostic | severity: :deny}
+      %{diagnostic | severity: :error}
     else
       diagnostic
     end
   end
 
+  @doc "Formats a diagnostic's location as `file:line:column`, `file`, or `nil` without a file."
+  @spec location(OXC.Diagnostic.t()) :: String.t() | nil
+  def location(%{file: nil}), do: nil
+  def location(%{file: file, position: {line, column}}), do: "#{file}:#{line}:#{column}"
+  def location(%{file: file}), do: file
+
   def type_check_diagnostic?(rule) do
     rule
     |> to_string()
     |> String.match?(~r/^(typescript\/)?TS\d+$/)
   end
 
-  def lint_error_message(%{message: message}), do: message
-  def lint_error_message(message) when is_binary(message), do: message
-  def lint_error_message(message), do: inspect(message)
-
-  defp ast_lint(files, config, rules) do
-    plugins = Keyword.get(config, :plugins, [:typescript])
-    custom_rules = Keyword.get(config, :custom_rules, [])
-
+  defp ast_lint(files, config) do
     Enum.flat_map(files, fn file ->
       source = File.read!(file)
+      options = Volt.JS.Lint.Config.options(config, file)
 
-      case OXC.Lint.run(source, file,
-             plugins: plugins,
-             rules: rules,
-             custom_rules: custom_rules
-           ) do
-        {:ok, diagnostics} -> Enum.map(diagnostics, &Map.put(&1, :file, file))
-        {:error, errors} -> Enum.map(errors, &lint_error(&1, file))
+      case OXC.Lint.run(source, file, options) do
+        {:ok, diagnostics} -> diagnostics
+        {:error, errors} -> errors
       end
     end)
   end
 
-  defp type_aware_lint(files, config, rules, opts) do
-    {files, source_overrides, source_files} = type_aware_inputs(files, config)
+  defp type_aware_lint(files, config, lint_config, opts) do
+    inputs = type_aware_inputs(files)
 
-    lint_opts =
+    # Declarations are resolved from imports, so they are not checked files
+    # and need no place in a project; the overlay only lists the modules.
+    common_opts =
       [
         type_aware: true,
         type_check: opts[:type_check] == true,
-        rules: rules,
-        source_overrides: Map.merge(source_overrides, Keyword.get(config, :source_overrides, %{}))
+        source_overrides:
+          inputs.overrides
+          |> Map.merge(Volt.JS.Lint.TSConfigOverlay.overrides(Map.keys(inputs.overrides)))
+          |> Map.merge(inputs.declarations)
+          |> Map.merge(Keyword.get(config, :source_overrides, %{}))
       ] ++ type_aware_options(config)
 
-    case run_type_aware_lint(files, lint_opts) do
-      {:ok, diagnostics} ->
-        Enum.map(diagnostics, fn diagnostic ->
-          diagnostic
-          |> restore_sfc_file(source_files)
-          |> promote_type_check_diagnostic(opts)
-        end)
+    source_files = inputs.source_files
 
-      {:error, errors} ->
-        Enum.map(errors, &lint_error/1)
-    end
+    inputs.files
+    |> Enum.group_by(fn file ->
+      original = Map.get(source_files, Path.expand(file), file)
+      lint_config |> Volt.JS.Lint.Config.options(original) |> OXC.Lint.type_aware_rules()
+    end)
+    |> Enum.sort_by(fn {rules, _files} -> rules end)
+    |> Enum.flat_map(fn
+      {{:ok, rules}, batch} ->
+        case run_type_aware_lint(batch, Keyword.put(common_opts, :rules, rules)) do
+          {:ok, diagnostics} ->
+            Enum.map(diagnostics, fn diagnostic ->
+              diagnostic |> restore_sfc_file(source_files) |> promote_type_check_diagnostic(opts)
+            end)
+
+          {:error, errors} ->
+            errors
+        end
+
+      {{:error, errors}, _batch} ->
+        errors
+    end)
   end
 
-  defp type_aware_inputs(files, config) do
-    plugins = Keyword.get(config, :plugins, [])
+  # The files tsgolint checks, with the virtual modules of plugin-owned files
+  # such as `.vue` scripts among them, the sources of those modules, the files
+  # they came from, and the declarations imports of plugin-owned files resolve
+  # to.
+  defp type_aware_inputs(files) do
+    plugins = Volt.Config.build().plugins
+    inputs = %{files: [], overrides: %{}, source_files: %{}, declarations: %{}}
 
-    Enum.reduce(files, {[], %{}, %{}}, fn file, {files, overrides, source_files} ->
+    files
+    |> Enum.reduce(inputs, fn file, inputs ->
       if type_aware_file?(file) do
-        {[file | files], overrides, source_files}
+        %{inputs | files: [file | inputs.files]}
       else
+        source = File.read!(file)
+
         file
-        |> embedded_modules(plugins)
-        |> Enum.reduce({files, overrides, source_files}, fn module, acc ->
-          add_embedded_module(acc, file, module)
-        end)
+        |> embedded_modules(plugins, source)
+        |> Enum.reduce(inputs, &add_embedded_module(&2, file, &1))
+        |> add_declaration(file, Volt.PluginRunner.declaration(plugins, file, source, []))
       end
     end)
-    |> then(fn {files, overrides, source_files} ->
-      {Enum.reverse(files), overrides, source_files}
-    end)
+    |> Map.update!(:files, &Enum.reverse/1)
   end
 
   defp type_aware_file?(file), do: Path.extname(file) in Volt.JS.Extensions.bundleable()
 
-  defp embedded_modules(file, plugins) do
-    Volt.PluginRunner.embedded_modules(plugins, file, File.read!(file), [])
+  defp embedded_modules(file, plugins, source) do
+    Volt.PluginRunner.embedded_modules(plugins, file, source, [])
   end
 
-  defp add_embedded_module({files, overrides, source_files}, file, module) do
+  defp add_embedded_module(inputs, file, module) do
     virtual_file = "#{file}.#{module.type}#{module.index}#{module.extension}"
     expanded = Path.expand(virtual_file)
 
-    {
-      [virtual_file | files],
-      Map.put(overrides, expanded, module.source),
-      Map.put(source_files, expanded, file)
+    %{
+      inputs
+      | files: [virtual_file | inputs.files],
+        overrides: Map.put(inputs.overrides, expanded, module.source),
+        source_files: Map.put(inputs.source_files, expanded, file)
     }
   end
 
+  # TypeScript resolves an import of `Button.vue` to `Button.vue.d.ts`, so a
+  # generated declaration under that name types the import without a
+  # `declare module "*.vue"` shim. A declaration the project wrote itself
+  # under that name is kept.
+  defp add_declaration(inputs, file, {:ok, declaration}) do
+    path = Path.expand("#{file}.d.ts")
+
+    if File.regular?(path),
+      do: inputs,
+      else: %{inputs | declarations: Map.put(inputs.declarations, path, declaration)}
+  end
+
+  defp add_declaration(inputs, _file, _none), do: inputs
+
   defp restore_sfc_file(diagnostic, source_files) do
     case Map.fetch(source_files, diagnostic.file) do
       {:ok, file} -> %{diagnostic | file: file}
@@ -167,28 +200,16 @@ defmodule Volt.JS.Check do
 
   defp unknown_tsgolint_rule(errors) do
     Enum.find_value(errors, fn error ->
-      case Regex.run(~r/unknown rule: ([\w-]+)/, lint_error_message(error)) do
+      case Regex.run(~r/unknown rule: ([\w-]+)/, error.message) do
         [_, rule] -> rule
         _ -> nil
       end
     end)
   end
 
-  defp typescript_rules(rules) do
-    Map.filter(rules, fn {rule, _config} ->
-      String.starts_with?(to_string(rule), "typescript/")
-    end)
-  end
-
   defp type_aware_options(config) do
     config
     |> Keyword.take([:tsgolint, :fix, :fix_suggestions, :cwd])
     |> Enum.reject(fn {_key, value} -> is_nil(value) end)
   end
-
-  defp lint_error(message), do: lint_error(message, "volt.js.check")
-
-  defp lint_error(message, file) do
-    %{severity: :deny, file: file, message: lint_error_message(message), rule: "oxc/lint"}
-  end
 end
diff --git a/lib/volt/js/common_js.ex b/lib/volt/js/common_js.ex
new file mode 100644
index 0000000..6b83d95
--- /dev/null
+++ b/lib/volt/js/common_js.ex
@@ -0,0 +1,103 @@
+defmodule Volt.JS.CommonJS do
+  @moduledoc """
+  Detects local CommonJS/UMD modules and converts them to ES modules for the dev server.
+
+  Production builds hand CommonJS files to the bundler, which wraps them itself.
+  The dev server serves each file as a native ES module, so a CommonJS file such
+  as Phoenix's vendored `topbar.js` needs the same interop before a browser can
+  `import topbar from "../vendor/topbar"`.
+  """
+
+  @esm_declarations [
+    :import_declaration,
+    :export_named_declaration,
+    :export_default_declaration,
+    :export_all_declaration
+  ]
+
+  @doc """
+  Return whether the module at `path` is CommonJS/UMD rather than an ES module.
+
+  `.cjs` and `.cts` files are CommonJS by extension. A `.js` file is CommonJS
+  when it has no `import` or `export` declarations and uses `module.exports`,
+  `exports`, or `require`.
+  """
+  @spec commonjs?(String.t(), String.t()) :: boolean()
+  def commonjs?(source, path) do
+    ext = Path.extname(path)
+
+    cond do
+      ext in Volt.JS.Extensions.cjs() -> true
+      ext == ".js" -> commonjs_source?(source, Path.basename(path))
+      true -> false
+    end
+  end
+
+  defp commonjs_source?(source, filename) do
+    case OXC.parse(source, filename) do
+      {:ok, ast} -> not esm?(ast) and uses_commonjs?(ast)
+      {:error, _} -> false
+    end
+  end
+
+  @doc """
+  Bundle the CommonJS file at `path` into an ES module whose default export is
+  `module.exports`. Modules it requires are bundled along with it.
+
+  ## Options
+
+    * `:modules` — directories used to resolve bare `require` specifiers
+    * `:module_types` — bundler module type overrides
+  """
+  @spec to_esm(String.t(), keyword()) :: {:ok, String.t()} | {:error, term()}
+  def to_esm(path, opts \\ []) do
+    module_types = Keyword.get(opts, :module_types, %{})
+
+    bundle_opts =
+      [
+        cwd: Path.dirname(path),
+        format: :esm,
+        conditions: Volt.JS.Resolution.browser_conditions(),
+        modules: Keyword.get(opts, :modules, []),
+        define: %{"process.env.NODE_ENV" => ~s("development")}
+      ] ++ if(module_types != %{}, do: [module_types: module_types], else: [])
+
+    case OXC.bundle(path, bundle_opts) do
+      {:ok, %{code: code}} -> {:ok, code}
+      {:ok, code} when is_binary(code) -> {:ok, code}
+      {:error, _} = error -> error
+    end
+  end
+
+  defp esm?(%{body: body}) when is_list(body) do
+    Enum.any?(body, &(&1[:type] in @esm_declarations))
+  end
+
+  defp esm?(_ast), do: false
+
+  defp uses_commonjs?(ast) do
+    {_ast, found?} =
+      OXC.postwalk(ast, false, fn
+        node, false -> {node, commonjs_node?(node)}
+        node, true -> {node, true}
+      end)
+
+    found?
+  end
+
+  defp commonjs_node?(node) when is_map(node) do
+    Volt.JS.AST.member_expression?(node, "module", "exports") or
+      exports_member?(node) or
+      match?({:ok, _}, Volt.JS.AST.call_arguments(node, "require"))
+  end
+
+  defp commonjs_node?(_node), do: false
+
+  defp exports_member?(%{
+         type: :member_expression,
+         object: %{type: :identifier, name: "exports"}
+       }),
+       do: true
+
+  defp exports_member?(_node), do: false
+end
diff --git a/lib/volt/js/helpers.ex b/lib/volt/js/discovery.ex
similarity index 54%
rename from lib/volt/js/helpers.ex
rename to lib/volt/js/discovery.ex
index 1198836..aeff5b7 100644
--- a/lib/volt/js/helpers.ex
+++ b/lib/volt/js/discovery.ex
@@ -1,11 +1,12 @@
-defmodule Volt.JS.Helpers do
+defmodule Volt.JS.Discovery do
   @moduledoc "Shared JavaScript file discovery helpers for Mix tasks."
 
-  def discover_files(opts \\ []) do
+  def files(opts \\ []) do
     config = Volt.Config.build()
-    root = config.root
-    sources = config.sources
-    ignore = config.ignore
+    tool_config = discovery_config(Keyword.get(opts, :tool))
+    root = Keyword.get(tool_config, :root, config.root)
+    sources = Keyword.get(tool_config, :sources, config.sources)
+    ignore = Keyword.get(tool_config, :ignore, config.ignore)
     only = Keyword.get(opts, :only)
 
     matched =
@@ -32,7 +33,12 @@ defmodule Volt.JS.Helpers do
     |> Enum.sort()
   end
 
-  def discover_format_files do
-    discover_files(only: Volt.JS.Extensions.formattable())
+  def format_files do
+    files(tool: :format, only: Volt.JS.Extensions.formattable())
   end
+
+  defp discovery_config(nil), do: []
+
+  defp discovery_config(:format), do: Volt.JS.Format.discovery_config()
+  defp discovery_config(tool), do: Application.get_env(:volt, tool, [])
 end
diff --git a/lib/volt/js/extensions.ex b/lib/volt/js/extensions.ex
index 6717b7f..86b8673 100644
--- a/lib/volt/js/extensions.ex
+++ b/lib/volt/js/extensions.ex
@@ -9,12 +9,16 @@ defmodule Volt.JS.Extensions do
 
   def js, do: @js
   def cjs, do: @cjs
+
   def json, do: @json
   def node_resolvable, do: @js ++ @cjs ++ @json
   def node_resolvable_with_exact, do: ["" | node_resolvable()]
   def bundleable, do: @js ++ @cjs
   def formattable, do: @js
-  def compilable(plugins \\ []), do: plugin_exts(plugins, :compile) ++ @js ++ @css ++ @json
+
+  def compilable(plugins \\ []),
+    do: plugin_exts(plugins, :compile) ++ @js ++ @cjs ++ @css ++ @json
+
   def scannable(plugins \\ []), do: plugin_exts(plugins, :scan) ++ @js
   def resolvable(plugins \\ []), do: ["" | @js ++ @cjs ++ plugin_exts(plugins, :resolve) ++ @json]
   def resolvable_index, do: Enum.map(@js ++ @cjs, &("/index" <> &1))
diff --git a/lib/volt/js/format.ex b/lib/volt/js/format.ex
index af691a7..51058c7 100644
--- a/lib/volt/js/format.ex
+++ b/lib/volt/js/format.ex
@@ -24,14 +24,54 @@ defmodule Volt.JS.Format do
   }
 
   @atom_values ~w(trailing_comma arrow_parens end_of_line quote_props object_wrap experimental_operator_position embedded_language_formatting)a
+  @discovery_keys ~w(root sources ignore)a
 
-  def load_config do
-    case Application.get_env(:volt, :format) do
-      nil -> load_json_config()
-      opts when is_list(opts) -> opts
+  @dot_formatter ".formatter.exs"
+
+  @doc """
+  Load oxfmt options.
+
+  Options come from the `:volt` key of `.formatter.exs`:
+
+      [
+        plugins: [Volt.Formatter],
+        volt: [semi: false, single_quote: true]
+      ]
+
+  Without that key, they come from `.oxfmtrc.json` or `.prettierrc.json`.
+  `formatter_opts` is the keyword list `.formatter.exs` evaluates to; `mix format`
+  passes it to `Volt.Formatter`, and the Mix tasks read the file themselves.
+  """
+  @spec load_config(keyword()) :: keyword()
+  def load_config(formatter_opts \\ formatter_opts()) do
+    Volt.Config.reject_formatter_options!(Application.get_env(:volt, :format))
+
+    case Keyword.fetch(formatter_opts, :volt) do
+      {:ok, opts} -> Keyword.drop(opts, @discovery_keys)
+      :error -> load_json_config()
     end
   end
 
+  @doc "Read the options in the project's `.formatter.exs`, or `[]` without one."
+  @spec formatter_opts() :: keyword()
+  def formatter_opts do
+    if File.regular?(@dot_formatter) do
+      {opts, _binding} = Code.eval_file(@dot_formatter)
+      opts
+    else
+      []
+    end
+  end
+
+  @doc """
+  File-discovery options (`:root`, `:sources`, `:ignore`) for `mix volt.js.format`
+  and `mix volt.js.check`, from the `:volt` key of `.formatter.exs`.
+  """
+  @spec discovery_config(keyword()) :: keyword()
+  def discovery_config(formatter_opts \\ formatter_opts()) do
+    formatter_opts |> Keyword.get(:volt, []) |> Keyword.take(@discovery_keys)
+  end
+
   def load_json_config do
     case find_json_config() do
       nil -> []
diff --git a/lib/volt/js/imports/extractor.ex b/lib/volt/js/import_extractor.ex
similarity index 100%
rename from lib/volt/js/imports/extractor.ex
rename to lib/volt/js/import_extractor.ex
diff --git a/lib/volt/js/imports/result.ex b/lib/volt/js/import_extractor/result.ex
similarity index 100%
rename from lib/volt/js/imports/result.ex
rename to lib/volt/js/import_extractor/result.ex
diff --git a/lib/volt/js/lint/config.ex b/lib/volt/js/lint/config.ex
new file mode 100644
index 0000000..f28c4b8
--- /dev/null
+++ b/lib/volt/js/lint/config.ex
@@ -0,0 +1,130 @@
+defmodule Volt.JS.Lint.Config do
+  @moduledoc """
+  Resolves lint options for a source file without reading the filesystem.
+
+  Plugin, rule, environment, and global names are strings, as in an oxlint
+  config file.
+
+  Override globs are relative to the lint discovery root. Every matching override
+  is applied in declaration order; later entries replace individual rules,
+  environments and globals, not their entire maps. Environment lists enable
+  names; environment maps can also disable inherited names.
+  """
+
+  @enforce_keys [:root, :options, :overrides]
+  defstruct [:root, :options, :overrides]
+
+  @type t :: %__MODULE__{
+          root: String.t(),
+          options: keyword(),
+          overrides: [{[GlobEx.t()], keyword()}]
+        }
+
+  @doc "Compiles a lint configuration, using the build root unless lint sets its own root."
+  @spec new(keyword(), String.t()) :: t()
+  def new(config, root) do
+    options =
+      [plugins: ["typescript"], custom_rules: [], fix: false]
+      |> Keyword.merge(Keyword.take(config, [:plugins, :custom_rules, :fix]))
+      |> Keyword.merge(maps(config))
+
+    names!(options[:plugins], :plugins)
+
+    overrides =
+      Enum.map(Keyword.get(config, :overrides, []), fn override ->
+        override = Map.new(override)
+        unknown = Map.keys(override) -- [:files, :rules, :env, :globals]
+
+        if unknown != [] do
+          raise ArgumentError, "unsupported lint override keys: #{inspect(unknown)}"
+        end
+
+        globs =
+          case Map.fetch(override, :files) do
+            {:ok, [_ | _] = files} ->
+              Enum.map(files, &compile_glob!/1)
+
+            _ ->
+              raise ArgumentError,
+                    "lint override :files must be a non-empty list of relative globs"
+          end
+
+        {globs, maps(Map.to_list(override))}
+      end)
+
+    %__MODULE__{
+      root: Path.expand(Keyword.get(config, :root, root)),
+      options: options,
+      overrides: overrides
+    }
+  end
+
+  @doc "Returns effective OXC syntax-lint options for the original source path."
+  @spec options(t(), String.t()) :: keyword()
+  def options(%__MODULE__{} = config, file) do
+    relative = file |> Path.expand() |> Path.relative_to(config.root)
+
+    if Path.type(relative) == :relative and List.first(Path.split(relative)) != ".." do
+      relative = relative |> Path.split() |> Enum.join("/")
+
+      config.overrides
+      |> Enum.reduce(config.options, &apply_override(&1, relative, &2))
+      |> enabled_environments()
+    else
+      enabled_environments(config.options)
+    end
+  end
+
+  defp enabled_environments(options) do
+    Keyword.update!(options, :env, fn env -> for {name, true} <- env, do: name end)
+  end
+
+  defp apply_override({globs, options}, relative, inherited) do
+    if Enum.any?(globs, &GlobEx.match?(&1, relative)) do
+      Keyword.merge(inherited, options, fn _key, base, override -> Map.merge(base, override) end)
+    else
+      inherited
+    end
+  end
+
+  defp maps(config) do
+    [
+      rules: named!(Keyword.get(config, :rules, %{}), :rules),
+      globals: named!(Keyword.get(config, :globals, %{}), :globals),
+      env: environments!(Keyword.get(config, :env, []))
+    ]
+  end
+
+  defp environments!(env) when is_list(env), do: env |> names!(:env) |> Map.new(&{&1, true})
+  defp environments!(env) when is_map(env), do: named!(env, :env)
+
+  defp named!(map, key) when is_map(map) do
+    names!(Map.keys(map), key)
+    map
+  end
+
+  defp names!(names, key) do
+    unless is_list(names) and Enum.all?(names, &is_binary/1) do
+      raise ArgumentError, "lint #{inspect(key)} names must be strings, got: #{inspect(names)}"
+    end
+
+    names
+  end
+
+  defp compile_glob!(pattern) when is_binary(pattern) do
+    if Path.type(pattern) != :relative or ".." in Path.split(pattern) do
+      raise ArgumentError,
+            "lint override globs must stay relative to the lint root: #{inspect(pattern)}"
+    end
+
+    pattern
+    |> Path.split()
+    |> Enum.reject(&(&1 == "."))
+    |> Enum.join("/")
+    |> GlobEx.compile!(match_dot: true)
+  end
+
+  defp compile_glob!(pattern) do
+    raise ArgumentError, "lint override glob must be a string, got: #{inspect(pattern)}"
+  end
+end
diff --git a/lib/volt/js/lint/tsconfig_overlay.ex b/lib/volt/js/lint/tsconfig_overlay.ex
new file mode 100644
index 0000000..718087c
--- /dev/null
+++ b/lib/volt/js/lint/tsconfig_overlay.ex
@@ -0,0 +1,99 @@
+defmodule Volt.JS.Lint.TSConfigOverlay do
+  @moduledoc """
+  Puts virtual modules, such as the scripts of a `.vue` file, into the TypeScript
+  project that covers them.
+
+  tsgolint assigns a file to a project by the nearest `tsconfig.json` that
+  includes it, and expands `include` by listing directories on disk. A virtual
+  module is not on disk, so it lands in an inferred project with default
+  options: the project's `paths` do not apply to it, and the declaration files
+  the project includes are not in its program.
+
+  tsgolint does read file contents, and a `tsconfig.json` among them, through
+  the same overrides that carry the virtual modules. So the nearest
+  `tsconfig.json` is overridden with one that extends the original and names
+  the virtual modules in `files`. The original is carried unchanged under
+  another name beside it, so relative paths in it keep their meaning.
+  """
+
+  @base "tsconfig.volt-base.json"
+
+  @doc """
+  Return the source overrides that add `virtual_files` to their projects.
+
+  A virtual module without a `tsconfig.json` above it, or whose `tsconfig.json`
+  cannot be read as an object, is left to the inferred project.
+  """
+  @spec overrides([String.t()]) :: %{String.t() => String.t()}
+  def overrides(virtual_files) do
+    virtual_files
+    |> Enum.group_by(&nearest_tsconfig(Path.dirname(&1)))
+    |> Enum.flat_map(fn
+      {nil, _files} -> []
+      {tsconfig, files} -> project(tsconfig, Enum.sort(files))
+    end)
+    |> Map.new()
+  end
+
+  defp nearest_tsconfig(dir) do
+    tsconfig = Path.join(dir, "tsconfig.json")
+    parent = Path.dirname(dir)
+
+    cond do
+      File.regular?(tsconfig) -> tsconfig
+      parent == dir -> nil
+      true -> nearest_tsconfig(parent)
+    end
+  end
+
+  defp project(tsconfig, virtual_files) do
+    with {:ok, source} <- File.read(tsconfig),
+         {:ok, properties} <- properties(source) do
+      [
+        {Path.join(Path.dirname(tsconfig), @base), source},
+        {tsconfig, Jason.encode!(extending(properties, virtual_files))}
+      ]
+    else
+      _unreadable -> []
+    end
+  end
+
+  # `files` in a config replaces the `files` of the config it extends, and a
+  # config with `files` and no `include` includes nothing else. So the original's
+  # own `files` are repeated, and the default `include` is spelled out when the
+  # original relied on it.
+  defp extending(properties, virtual_files) do
+    config = %{
+      "extends" => "./" <> @base,
+      "files" => string_elements(properties["files"]) ++ virtual_files
+    }
+
+    if Enum.any?(["files", "include", "extends"], &Map.has_key?(properties, &1)),
+      do: config,
+      else: Map.put(config, "include", ["**/*"])
+  end
+
+  # A tsconfig may have comments and trailing commas, which makes it a
+  # JavaScript object literal rather than JSON.
+  defp properties(source) do
+    case OXC.parse("(" <> source <> "\n)", "tsconfig.js") do
+      {:ok, %{body: [%{expression: %{expression: %{type: :object_expression} = object}}]}} ->
+        properties =
+          for %{key: key, value: value} <- object.properties,
+              {:ok, name} <- [Volt.JS.AST.property_key(key)],
+              into: %{},
+              do: {name, value}
+
+        {:ok, properties}
+
+      _other ->
+        :error
+    end
+  end
+
+  defp string_elements(%{type: :array_expression, elements: elements}) do
+    for %{type: :literal, value: value} <- elements, is_binary(value), do: value
+  end
+
+  defp string_elements(_absent), do: []
+end
diff --git a/lib/volt/js/package.ex b/lib/volt/js/package.ex
index b5796ad..02bb385 100644
--- a/lib/volt/js/package.ex
+++ b/lib/volt/js/package.ex
@@ -1,6 +1,54 @@
 defmodule Volt.JS.Package do
   @moduledoc false
 
+  @doc """
+  The real directories of the packages in `node_modules` that are links to
+  somewhere outside it, such as path dependencies and `npm link`ed packages.
+
+  Their files change in place, unlike installed packages, which change only
+  with the lockfile.
+  """
+  @spec linked_dirs(Path.t() | nil) :: [Path.t()]
+  def linked_dirs(nil), do: []
+
+  def linked_dirs(node_modules) do
+    node_modules = Path.expand(node_modules)
+
+    node_modules
+    |> package_dirs()
+    |> Enum.flat_map(fn dir ->
+      with {:ok, %File.Stat{type: :symlink}} <- File.lstat(dir),
+           {:ok, target} <- File.read_link(dir),
+           real = Path.expand(target, Path.dirname(dir)),
+           false <- Volt.Path.inside?(real, node_modules) do
+        [real]
+      else
+        _installed_or_unreadable -> []
+      end
+    end)
+    |> Enum.uniq()
+  end
+
+  defp package_dirs(node_modules) do
+    node_modules
+    |> entries()
+    |> Enum.flat_map(fn
+      "@" <> _ = scope ->
+        scope_dir = Path.join(node_modules, scope)
+        scope_dir |> entries() |> Enum.map(&Path.join(scope_dir, &1))
+
+      name ->
+        [Path.join(node_modules, name)]
+    end)
+  end
+
+  defp entries(dir) do
+    case File.ls(dir) do
+      {:ok, names} -> Enum.reject(names, &String.starts_with?(&1, "."))
+      {:error, _reason} -> []
+    end
+  end
+
   def subpath_for(specifier) do
     case NPM.Resolution.PackageResolver.split_specifier(specifier) do
       {_, nil} -> "."
diff --git a/lib/volt/js/prebundle/entry.ex b/lib/volt/js/prebundle_entry.ex
similarity index 100%
rename from lib/volt/js/prebundle/entry.ex
rename to lib/volt/js/prebundle_entry.ex
diff --git a/lib/volt/js/prebundle/export.ex b/lib/volt/js/prebundle_entry/export.ex
similarity index 100%
rename from lib/volt/js/prebundle/export.ex
rename to lib/volt/js/prebundle_entry/export.ex
diff --git a/lib/volt/js/prebundle/import.ex b/lib/volt/js/prebundle_entry/import.ex
similarity index 100%
rename from lib/volt/js/prebundle/import.ex
rename to lib/volt/js/prebundle_entry/import.ex
diff --git a/lib/volt/js/runtime.ex b/lib/volt/js/runtime.ex
index c9274b4..3a50936 100644
--- a/lib/volt/js/runtime.ex
+++ b/lib/volt/js/runtime.ex
@@ -267,12 +267,24 @@ defmodule Volt.JS.Runtime do
 
   defp runtime_signature(opts) do
     opts
-    |> Keyword.take([:packages, :install_dir, :entry, :bundle])
+    |> Keyword.take([:packages, :install_dir, :entry, :bundle, :lockfile])
+    |> digest_lockfile()
     |> Enum.sort()
     |> :erlang.term_to_binary()
     |> :erlang.md5()
   end
 
+  defp digest_lockfile(opts) do
+    case Keyword.fetch(opts, :lockfile) do
+      {:ok, path} when is_binary(path) ->
+        digest = path |> File.read!() |> then(&:crypto.hash(:sha256, &1))
+        Keyword.put(opts, :lockfile, {:sha256, digest})
+
+      _ ->
+        opts
+    end
+  end
+
   defp maybe_put(opts, _key, nil), do: opts
   defp maybe_put(opts, key, value), do: Keyword.put(opts, key, value)
 end
diff --git a/lib/volt/js/runtime/installer.ex b/lib/volt/js/runtime/installer.ex
index 21f5413..31c5093 100644
--- a/lib/volt/js/runtime/installer.ex
+++ b/lib/volt/js/runtime/installer.ex
@@ -16,12 +16,13 @@ defmodule Volt.JS.Runtime.Installer do
   def install!(packages, opts \\ []) when is_map(packages) do
     Application.ensure_all_started(:req)
 
-    id = install_id(packages)
+    source_lock = read_source_lock!(packages, opts[:lockfile])
+    id = install_id(packages, source_lock)
     install_dir = Keyword.get(opts, :install_dir, default_install_dir(id))
     node_modules = Path.join(install_dir, "node_modules")
     lockfile_path = Path.join(install_dir, "npm.lock")
     metadata_path = Path.join(install_dir, "volt-runtime.json")
-    signature = install_signature(packages)
+    signature = install_signature(packages, source_lock)
 
     with_lock(install_dir, fn ->
       if Keyword.get(opts, :force, false) or metadata_mismatch?(metadata_path, signature) do
@@ -30,7 +31,7 @@ defmodule Volt.JS.Runtime.Installer do
 
       unless install_intact?(lockfile_path, node_modules, metadata_path, signature) do
         File.mkdir_p!(install_dir)
-        resolve_and_link!(packages, node_modules, lockfile_path)
+        install_packages!(packages, source_lock, node_modules, lockfile_path)
         write_metadata!(metadata_path, signature, packages)
       end
     end)
@@ -38,15 +39,30 @@ defmodule Volt.JS.Runtime.Installer do
     %{install_dir: install_dir, node_modules: node_modules}
   end
 
+  defp install_packages!(packages, nil, node_modules, lockfile_path) do
+    resolve_and_link!(packages, node_modules, lockfile_path)
+  end
+
+  defp install_packages!(_packages, source_lock, node_modules, lockfile_path) do
+    File.cp!(source_lock.path, lockfile_path)
+    link!(source_lock.packages, node_modules)
+    warn_ignored_install_scripts(source_lock.packages)
+  end
+
   defp resolve_and_link!(packages, node_modules, lockfile_path) do
     NPM.Resolver.clear_cache()
 
     case NPM.Resolver.resolve(packages) do
       {:ok, resolved} ->
-        {_nested, flat} = Map.pop(resolved, :nested, %{})
-        lockfile = build_lockfile(flat)
+        {nested, flat} = Map.pop(resolved, :nested, %{})
+
+        lockfile =
+          flat
+          |> NPM.Install.LockfileBuilder.build(&ignore_age_warning/3)
+          |> NPM.Install.NestedLockfile.add(nested, &ignore_age_warning/3)
+
         NPM.Lockfile.write(lockfile, lockfile_path)
-        NPM.Install.Linker.link(lockfile, node_modules)
+        link!(lockfile, node_modules)
         warn_ignored_install_scripts(lockfile)
 
       {:error, message} ->
@@ -54,23 +70,15 @@ defmodule Volt.JS.Runtime.Installer do
     end
   end
 
-  defp build_lockfile(resolved) do
-    for {name, version} <- resolved, into: %{} do
-      {:ok, packument} = NPM.Registry.get_packument(name)
-      info = Map.fetch!(packument.versions, version)
-
-      {name,
-       %{
-         version: version,
-         integrity: info.dist.integrity,
-         tarball: info.dist.tarball,
-         dependencies: info.dependencies,
-         optional_dependencies: info.optional_dependencies,
-         has_install_script: info.has_install_script
-       }}
+  defp link!(lockfile, node_modules) do
+    case NPM.Install.Linker.link(lockfile, node_modules) do
+      :ok -> :ok
+      {:error, reason} -> raise "NPM package installation failed: #{inspect(reason)}"
     end
   end
 
+  defp ignore_age_warning(_name, _version, _info), do: :ok
+
   defp warn_ignored_install_scripts(lockfile) do
     packages =
       lockfile
@@ -121,11 +129,102 @@ defmodule Volt.JS.Runtime.Installer do
     File.write!(metadata_path, Jason.encode!(metadata))
   end
 
-  defp install_id(packages), do: install_signature(packages)
+  defp read_source_lock!(_packages, nil), do: nil
+
+  defp read_source_lock!(packages, path) when is_binary(path) do
+    path = Path.expand(path)
+    contents = File.read!(path)
+
+    unless NPM.Lockfile.version(path) == 1 do
+      raise ArgumentError, "expected npm lockfile version 1, got: #{inspect(path)}"
+    end
+
+    {:ok, policy} = NPM.Lockfile.read_policy(path)
+
+    unless NPM.Lockfile.policy_matches?(policy) do
+      raise ArgumentError,
+            "npm lockfile security policy does not match current configuration: #{path}"
+    end
+
+    {:ok, lockfile} = NPM.Lockfile.read(path)
+    validate_source_lock!(packages, lockfile, path)
+    validate_lock_entries!(lockfile, lockfile, path)
+
+    %{
+      path: path,
+      packages: lockfile,
+      digest: :crypto.hash(:sha256, contents)
+    }
+  end
+
+  defp read_source_lock!(_packages, path) do
+    raise ArgumentError, "expected :lockfile to be a path, got: #{inspect(path)}"
+  end
+
+  defp validate_source_lock!(packages, lockfile, path) do
+    Enum.each(packages, fn {name, version} ->
+      case lockfile do
+        %{^name => %{version: ^version}} ->
+          :ok
+
+        %{^name => %{version: locked_version}} ->
+          raise ArgumentError,
+                "npm lockfile version mismatch for #{name}: expected #{version}, got #{locked_version} in #{path}"
 
-  defp install_signature(packages) do
+        _ ->
+          raise ArgumentError, "npm lockfile is missing direct package #{name}: #{path}"
+      end
+    end)
+  end
+
+  defp validate_lock_entries!(entries, root_lockfile, path) do
+    Enum.each(entries, fn {name, entry} ->
+      if entry.integrity == "" or entry.tarball == "" do
+        raise ArgumentError, "npm lockfile has incomplete package metadata for #{name}: #{path}"
+      end
+
+      NPM.Security.RegistryPolicy.validate_url!(entry.tarball)
+
+      Enum.each(entry.dependencies, fn {dependency, requirement} ->
+        nested_entry = Map.get(entry.nested_dependencies, dependency)
+        root_entry = Map.get(root_lockfile, dependency)
+
+        unless locked_requirement?(nested_entry, requirement) or
+                 locked_requirement?(root_entry, requirement) do
+          raise ArgumentError,
+                "npm lockfile does not satisfy #{name} dependency #{dependency}@#{requirement}: #{path}"
+        end
+      end)
+
+      validate_lock_entries!(entry.nested_dependencies, root_lockfile, path)
+    end)
+  end
+
+  defp locked_requirement?(nil, _requirement), do: false
+
+  defp locked_requirement?(entry, requirement) do
+    NPMSemver.matches?(entry.version, requirement)
+  rescue
+    ArgumentError -> false
+  end
+
+  defp install_id(packages, source_lock), do: install_signature(packages, source_lock)
+
+  defp install_signature(packages, nil) do
+    packages
+    |> Enum.sort()
+    |> hash_install_signature()
+  end
+
+  defp install_signature(packages, source_lock) do
     packages
     |> Enum.sort()
+    |> then(&{&1, source_lock.digest})
+    |> hash_install_signature()
+  end
+
+  defp hash_install_signature(value) do
+    value
     |> :erlang.term_to_binary()
     |> :erlang.md5()
     |> Base.encode16(case: :lower)
diff --git a/lib/volt/js/runtime/package_set.ex b/lib/volt/js/runtime/package_set.ex
new file mode 100644
index 0000000..6e17418
--- /dev/null
+++ b/lib/volt/js/runtime/package_set.ex
@@ -0,0 +1,55 @@
+defmodule Volt.JS.Runtime.PackageSet do
+  @moduledoc false
+
+  alias Volt.JS.Runtime.Installer
+
+  @enforce_keys [:app, :name, :packages]
+  defstruct [:app, :name, :packages]
+
+  @type t :: %__MODULE__{
+          app: atom(),
+          name: atom(),
+          packages: %{required(String.t()) => String.t()}
+        }
+
+  @spec bundled(atom(), atom(), map()) :: t()
+  def bundled(app, name, packages)
+      when is_atom(app) and is_atom(name) and is_map(packages) do
+    %__MODULE__{app: app, name: name, packages: packages}
+  end
+
+  @spec install!(t(), keyword()) :: %{install_dir: String.t(), node_modules: String.t()}
+  def install!(%__MODULE__{} = set, opts \\ []) do
+    Installer.install!(set.packages, lock_opts(set, opts))
+  end
+
+  @spec runtime_opts(t(), keyword()) :: keyword()
+  def runtime_opts(%__MODULE__{} = set, opts \\ []) do
+    set
+    |> lock_opts(opts)
+    |> Keyword.put(:packages, set.packages)
+  end
+
+  @spec lockfile_path(t()) :: String.t()
+  def lockfile_path(%__MODULE__{app: app, name: name}) do
+    Volt.Priv.path({app, "npm"}, "#{name}.lock")
+  end
+
+  defp lock_opts(set, opts) do
+    lockfile = lockfile_path(set)
+    opts = opts |> Keyword.delete(:packages) |> Keyword.delete(:lockfile)
+
+    if use_bundled_lock?(lockfile) do
+      Keyword.put(opts, :lockfile, lockfile)
+    else
+      opts
+    end
+  end
+
+  defp use_bundled_lock?(lockfile) do
+    case NPM.Lockfile.read_policy(lockfile) do
+      {:ok, policy} when is_map(policy) -> NPM.Lockfile.policy_matches?(policy)
+      _ -> true
+    end
+  end
+end
diff --git a/lib/volt/js/specifier.ex b/lib/volt/js/specifier.ex
index 032d2b4..1e7f6e6 100644
--- a/lib/volt/js/specifier.ex
+++ b/lib/volt/js/specifier.ex
@@ -16,6 +16,33 @@ defmodule Volt.JS.Specifier do
 
   def split_query(specifier), do: Volt.URL.split_query(specifier)
 
+  @doc """
+  Return whether a specifier names a Node.js built-in module, including a
+  subpath of one such as `timers/promises` or `node:fs/promises`.
+  """
+  @spec node_builtin?(String.t()) :: boolean()
+  def node_builtin?("node:" <> _rest), do: true
+
+  def node_builtin?(specifier) do
+    specifier
+    |> String.split("/", parts: 2)
+    |> hd()
+    |> NPM.Resolution.PackageResolver.node_builtin?()
+  end
+
+  @oxc_runtime "@oxc-project/runtime"
+
+  @doc """
+  Return whether a specifier names a helper from `@oxc-project/runtime`.
+
+  OXC's transform imports these when it lowers syntax for a target, such as
+  class fields below ES2022. `OXC.bundle/2` provides them itself, so they are
+  never resolved from `node_modules`.
+  """
+  @spec oxc_runtime_helper?(String.t()) :: boolean()
+  def oxc_runtime_helper?(specifier),
+    do: specifier == @oxc_runtime or String.starts_with?(specifier, @oxc_runtime <> "/")
+
   defp split_on_query(specifier) do
     case String.split(specifier, "?", parts: 2) do
       [path, query] -> {path, query}
diff --git a/lib/volt/js/transforms/glob_imports.ex b/lib/volt/js/transforms/glob_imports.ex
index 6a5be1a..17da1ad 100644
--- a/lib/volt/js/transforms/glob_imports.ex
+++ b/lib/volt/js/transforms/glob_imports.ex
@@ -224,6 +224,7 @@ defmodule Volt.JS.Transforms.GlobImports do
   end
 
   defp wildcard(pattern, base_dir, base) do
+    base_dir = Path.expand(base_dir)
     key_base_dir = key_base_dir(base, base_dir)
 
     Path.join(base_dir, pattern)
diff --git a/lib/volt/js/transforms/imports.ex b/lib/volt/js/transforms/imports.ex
index 9ac36ce..1538666 100644
--- a/lib/volt/js/transforms/imports.ex
+++ b/lib/volt/js/transforms/imports.ex
@@ -40,10 +40,7 @@ defmodule Volt.JS.Transforms.Imports do
   @spec rewrite!(String.t(), String.t(), (String.t() -> {:rewrite, String.t()} | :keep)) ::
           String.t()
   def rewrite!(source, filename, rewrite_fn) do
-    case rewrite(source, filename, rewrite_fn) do
-      {:ok, result} -> result
-      {:error, errors} -> raise "Import rewrite error: #{inspect(errors)}"
-    end
+    source |> rewrite(filename, rewrite_fn) |> OXC.Error.unwrap!()
   end
 
   @doc """
diff --git a/lib/volt/js/tsconfig.ex b/lib/volt/js/tsconfig.ex
index 363ef31..7e75258 100644
--- a/lib/volt/js/tsconfig.ex
+++ b/lib/volt/js/tsconfig.ex
@@ -15,7 +15,9 @@ defmodule Volt.JS.TSConfig do
       %{"@" => "/absolute/path/to/src"}
 
   Glob suffixes (`/*`) are stripped from both keys and values.
-  Only the first path in each mapping array is used.
+  The first path in each mapping array that is not a declaration file is used;
+  mappings that only point at declaration files (`.d.ts`) describe types and
+  are left to normal module resolution.
   """
   @spec read_paths(String.t()) :: %{String.t() => String.t()}
   def read_paths(tsconfig_path) do
@@ -26,24 +28,29 @@ defmodule Volt.JS.TSConfig do
       tsconfig_dir = Path.dirname(tsconfig_path)
       base = Path.expand(base_url, tsconfig_dir)
 
-      Map.new(paths, fn {key, targets} ->
-        alias_key = key |> String.trim_trailing("/*") |> String.trim_trailing("*")
-        alias_key = String.trim_trailing(alias_key, "/")
-
-        target =
-          targets
-          |> List.first("")
-          |> String.trim_trailing("/*")
-          |> String.trim_trailing("*")
-          |> String.trim_trailing("/")
-
-        {alias_key, Path.expand(target, base)}
-      end)
+      for {key, targets} <- paths,
+          target = Enum.find(List.wrap(targets), &runtime_target?/1),
+          into: %{} do
+        {trim_glob(key), Path.expand(trim_glob(target), base)}
+      end
     else
       _ -> %{}
     end
   end
 
+  defp runtime_target?(target) when is_binary(target) do
+    not String.ends_with?(target, [".d.ts", ".d.mts", ".d.cts"])
+  end
+
+  defp runtime_target?(_target), do: false
+
+  defp trim_glob(pattern) do
+    pattern
+    |> String.trim_trailing("/*")
+    |> String.trim_trailing("*")
+    |> String.trim_trailing("/")
+  end
+
   @doc """
   Find and read tsconfig.json paths from the current working directory.
   """
diff --git a/lib/volt/js/vendor.ex b/lib/volt/js/vendor.ex
index fa2c946..bd7a7cf 100644
--- a/lib/volt/js/vendor.ex
+++ b/lib/volt/js/vendor.ex
@@ -11,6 +11,15 @@ defmodule Volt.JS.Vendor do
   so conditional CJS branches resolve correctly.
 
   Bundled files are cached on disk in `_build/volt/vendor/`.
+
+  Vendor URLs carry a version, `?v=`, that browsers cache them under for
+  good. It changes with the module directories, lockfiles and plugins, and
+  with the generation of the pre-bundle: a hash over the signature of every
+  package bundled, written beside the bundles. A package that changed in
+  place, such as a linked one, is bundled again on the next pre-bundle, which
+  gives every vendor module a new URL. One URL for all of them is deliberate:
+  the bundles share chunks, and a browser mixing old and new ones would hold
+  two instances of a chunk.
   """
 
   require Logger
@@ -19,7 +28,17 @@ defmodule Volt.JS.Vendor do
 
   defp cache_dir do
     build_path = System.get_env("MIX_BUILD_PATH") || "_build"
-    Path.join(build_path, "volt/vendor")
+    Volt.Paths.expand(Path.join(build_path, "volt/vendor"))
+  end
+
+  @generation_file "generation"
+
+  defp context_dir(module_dirs, plugins, module_types),
+    do: context_dir(browser_signature(module_dirs, plugins, module_types))
+
+  defp context_dir(signature) when is_map(signature) do
+    hash = :crypto.hash(:sha256, :erlang.term_to_binary(signature)) |> Base.encode16(case: :lower)
+    Path.join(cache_dir(), hash)
   end
 
   @doc """
@@ -45,7 +64,7 @@ defmodule Volt.JS.Vendor do
     module_types = Keyword.get(opts, :module_types, %{})
 
     with {:ok, specifiers} <- scan_bare_imports(root, plugins),
-         :ok <- ensure_cache_dir() do
+         :ok <- ensure_cache_dir(module_dirs, plugins, module_types) do
       specifiers =
         specifiers
         |> Enum.map(&Volt.PluginRunner.prebundle_alias(plugins, &1))
@@ -65,9 +84,9 @@ defmodule Volt.JS.Vendor do
   @spec bundle_on_demand(String.t(), String.t() | nil, keyword()) ::
           {:ok, String.t()} | {:error, term()}
   def bundle_on_demand(specifier, node_modules, opts \\ []) do
-    ensure_cache_dir()
     {plugins, resolve_dirs, module_types} = normalize_on_demand_opts(opts)
     module_dirs = module_dirs(node_modules, resolve_dirs)
+    ensure_cache_dir(module_dirs, plugins, module_types)
     specifier = Volt.PluginRunner.prebundle_alias(plugins, specifier)
 
     case bundle_vendor(specifier, module_dirs, false, plugins, module_types) do
@@ -95,39 +114,63 @@ defmodule Volt.JS.Vendor do
   def current_browser_hash?(nil, _opts), do: true
   def current_browser_hash?(hash, opts), do: hash == browser_hash(opts)
 
-  @doc "Return the current browser hash for optimized dependency requests."
+  @doc """
+  Return the current browser hash for optimized dependency requests.
+
+  The hash covers the browser signature and the generation of the pre-bundle,
+  so it changes when a package is bundled again.
+  """
   @spec browser_hash(keyword()) :: String.t()
   def browser_hash(opts) do
     {plugins, resolve_dirs, module_types} = normalize_on_demand_opts(opts)
     node_modules = Keyword.get(opts, :node_modules)
     module_dirs = module_dirs(node_modules, resolve_dirs)
+    signature = browser_signature(module_dirs, plugins, module_types)
 
     :crypto.hash(
       :sha256,
-      :erlang.term_to_binary(browser_signature(module_dirs, plugins, module_types))
+      :erlang.term_to_binary({signature, read_generation(context_dir(signature))})
     )
     |> Base.encode16(case: :lower)
     |> binary_part(0, 8)
   end
 
+  @doc """
+  Return the generation of the pre-bundle for `opts`: a hash over the cache
+  signatures of the packages bundled, or `nil` before the first pre-bundle.
+  """
+  @spec generation(keyword()) :: String.t() | nil
+  def generation(opts) when is_list(opts) do
+    {plugins, resolve_dirs, module_types} = normalize_on_demand_opts(opts)
+    node_modules = Keyword.get(opts, :node_modules)
+    module_dirs = module_dirs(node_modules, resolve_dirs)
+    read_generation(context_dir(module_dirs, plugins, module_types))
+  end
+
+  defp read_generation(context_dir) do
+    case File.read(Path.join(context_dir, @generation_file)) do
+      {:ok, generation} -> generation
+      {:error, _reason} -> nil
+    end
+  end
+
   @doc """
   Read a pre-bundled vendor file by specifier.
   """
   @spec read(String.t()) :: {:ok, String.t()} | {:error, :not_found}
-  def read(specifier), do: read_cached(specifier)
+  def read(specifier), do: read(specifier, [])
 
   @doc "Read a pre-bundled vendor file when its cache signature matches the current options."
   @spec read(String.t(), keyword()) :: {:ok, String.t()} | {:error, :not_found}
-  def read("chunks/" <> _ = specifier, _opts), do: read_cached(specifier)
-
   def read(specifier, opts) do
     {plugins, resolve_dirs, module_types} = normalize_on_demand_opts(opts)
     node_modules = Keyword.get(opts, :node_modules)
     module_dirs = module_dirs(node_modules, resolve_dirs)
     specifier = Volt.PluginRunner.prebundle_alias(plugins, specifier)
 
-    if cache_fresh?(specifier, module_dirs, plugins, module_types) do
-      read_cached(specifier)
+    if String.starts_with?(specifier, "chunks/") or
+         cache_fresh?(specifier, module_dirs, plugins, module_types) do
+      read_cached(specifier, context_dir(module_dirs, plugins, module_types))
     else
       {:error, :not_found}
     end
@@ -186,12 +229,22 @@ defmodule Volt.JS.Vendor do
   defp prebundle_vendors([], _module_dirs, _force, _plugins, _module_types), do: {:ok, %{}}
 
   defp prebundle_vendors(specifiers, module_dirs, force, plugins, module_types) do
-    vendor_map = Map.new(specifiers, &{&1, cache_path(&1)})
+    # A bare import that resolves to no package, such as one a plugin or the
+    # host page provides, is never written to the cache. Counting it as stale
+    # would bundle every package again on each call.
+    specifiers =
+      Enum.filter(specifiers, &match?({:ok, _, _}, bundle_entry_for(&1, module_dirs, plugins)))
+
+    vendor_map = Map.new(specifiers, &{&1, cache_path(&1, module_dirs, plugins, module_types)})
 
     if not force and Enum.all?(specifiers, &cache_fresh?(&1, module_dirs, plugins, module_types)) do
       {:ok, vendor_map}
     else
-      safe_bundle_vendors(specifiers, module_dirs, plugins, module_types, vendor_map)
+      with {:ok, bundled} = ok <-
+             safe_bundle_vendors(specifiers, module_dirs, plugins, module_types, vendor_map) do
+        Logger.debug("[Volt] Pre-bundled #{map_size(bundled)} vendor package(s)")
+        ok
+      end
     end
   end
 
@@ -232,7 +285,7 @@ defmodule Volt.JS.Vendor do
       Bundle.new()
       |> Bundle.entries(bundle_entries)
       |> Bundle.cwd(project_root(module_dirs))
-      |> Bundle.outdir(cache_dir())
+      |> Bundle.outdir(context_dir(module_dirs, plugins, module_types))
       |> Bundle.format(:esm)
       |> Bundle.resolve(
         conditions: Volt.JS.Resolution.browser_conditions(),
@@ -262,13 +315,31 @@ defmodule Volt.JS.Vendor do
 
   defp write_vendor_cache_metadata(specifiers, module_dirs, plugins, module_types) do
     Enum.each(specifiers, fn specifier ->
-      if File.regular?(cache_path(specifier)) do
+      if File.regular?(cache_path(specifier, module_dirs, plugins, module_types)) do
         File.write!(
-          cache_meta_path(specifier),
+          cache_meta_path(specifier, module_dirs, plugins, module_types),
           cache_signature(specifier, module_dirs, plugins, module_types)
         )
       end
     end)
+
+    write_generation!(context_dir(module_dirs, plugins, module_types))
+  end
+
+  # The generation is a hash over every package's cache signature, so it
+  # changes whenever a package was bundled again, and the vendor URLs with it.
+  defp write_generation!(context_dir) do
+    signatures =
+      context_dir
+      |> Path.join("*.meta")
+      |> Path.wildcard()
+      |> Enum.sort()
+      |> Enum.map(&File.read!/1)
+
+    generation =
+      :crypto.hash(:sha256, :erlang.term_to_binary(signatures)) |> Base.encode16(case: :lower)
+
+    File.write!(Path.join(context_dir, @generation_file), generation)
   end
 
   defp fallback_bundle_vendors(specifiers, module_dirs, plugins, module_types) do
@@ -307,7 +378,7 @@ defmodule Volt.JS.Vendor do
   end
 
   defp bundle_vendor(specifier, module_dirs, force, plugins, module_types) do
-    path = cache_path(specifier)
+    path = cache_path(specifier, module_dirs, plugins, module_types)
 
     if not force and File.regular?(path) and
          cache_fresh?(specifier, module_dirs, plugins, module_types) do
@@ -318,7 +389,7 @@ defmodule Volt.JS.Vendor do
   end
 
   defp do_bundle_vendor(specifier, module_dirs, output_path, plugins, module_types) do
-    case prebundle_entry(specifier, module_dirs, plugins) do
+    case prebundle_entry(specifier, module_dirs, plugins, module_types) do
       {:ok, entry_path, project_root} ->
         bundle_opts =
           [
@@ -353,26 +424,42 @@ defmodule Volt.JS.Vendor do
     end
   end
 
-  defp prebundle_entry(specifier, module_dirs, plugins) do
+  defp prebundle_entry(specifier, module_dirs, plugins, module_types) do
     case Volt.PluginRunner.prebundle_entry(plugins, specifier) do
       {:source, filename, source} ->
-        synthetic_prebundle_entry(specifier, filename, source, module_dirs)
+        synthetic_prebundle_entry(
+          specifier,
+          filename,
+          source,
+          context_dir(module_dirs, plugins, module_types)
+        )
 
       {:proxy, filename, _opts} = entry ->
         synthetic_prebundle_entry(
           specifier,
           filename,
           Volt.JS.PrebundleEntry.source(entry),
-          module_dirs
+          context_dir(module_dirs, plugins, module_types)
         )
 
       nil ->
-        package_prebundle_entry(specifier, module_dirs)
+        if Volt.JS.Specifier.oxc_runtime_helper?(specifier) do
+          # The bundler supplies these helpers, so the entry only has to name
+          # one; the package does not need to be installed.
+          synthetic_prebundle_entry(
+            specifier,
+            "helper.js",
+            ~s(export { default } from #{Jason.encode!(specifier)};\n),
+            context_dir(module_dirs, plugins, module_types)
+          )
+        else
+          package_prebundle_entry(specifier, module_dirs)
+        end
     end
   end
 
-  defp synthetic_prebundle_entry(specifier, filename, source, _module_dirs) do
-    dir = Path.expand(Path.join([cache_dir(), "entries", encode_specifier(specifier)]))
+  defp synthetic_prebundle_entry(specifier, filename, source, directory) do
+    dir = Path.expand(Path.join([directory, "entries", encode_specifier(specifier)]))
     path = Path.join(dir, filename)
     File.mkdir_p!(dir)
     File.write!(path, source)
@@ -512,15 +599,15 @@ defmodule Volt.JS.Vendor do
   end
 
   defp project_root([module_dir | _]), do: Path.dirname(module_dir)
-  defp project_root([]), do: File.cwd!()
+  defp project_root([]), do: Volt.Paths.root()
 
-  defp ensure_cache_dir do
-    File.mkdir_p!(cache_dir())
+  defp ensure_cache_dir(module_dirs, plugins, module_types) do
+    File.mkdir_p!(context_dir(module_dirs, plugins, module_types))
     :ok
   end
 
-  defp read_cached("chunks/" <> _ = specifier) do
-    Path.join(cache_dir(), specifier <> ".js")
+  defp read_cached("chunks/" <> _ = specifier, directory) do
+    Path.join(directory, specifier <> ".js")
     |> File.read()
     |> case do
       {:ok, _} = ok -> ok
@@ -528,9 +615,9 @@ defmodule Volt.JS.Vendor do
     end
   end
 
-  defp read_cached(specifier) do
-    specifier
-    |> cache_path()
+  defp read_cached(specifier, directory) do
+    directory
+    |> Path.join(encode_specifier(specifier) <> ".js")
     |> File.read()
     |> case do
       {:ok, _} = ok -> ok
@@ -539,13 +626,13 @@ defmodule Volt.JS.Vendor do
   end
 
   defp cache_fresh?(specifier, module_dirs, plugins, module_types) do
-    File.regular?(cache_path(specifier)) and
-      File.read(cache_meta_path(specifier)) ==
+    File.regular?(cache_path(specifier, module_dirs, plugins, module_types)) and
+      File.read(cache_meta_path(specifier, module_dirs, plugins, module_types)) ==
         {:ok, cache_signature(specifier, module_dirs, plugins, module_types)}
   end
 
   defp write_cache_files!(output_path, code, specifier, module_dirs, plugins, module_types) do
-    meta_path = cache_meta_path(specifier)
+    meta_path = cache_meta_path(specifier, module_dirs, plugins, module_types)
     nonce = System.unique_integer([:positive])
     tmp_output = "#{output_path}.#{nonce}.tmp"
     tmp_meta = "#{meta_path}.#{nonce}.tmp"
@@ -620,7 +707,7 @@ defmodule Volt.JS.Vendor do
     end
   end
 
-  @lockfiles ~w(package-lock.json pnpm-lock.yaml yarn.lock bun.lock bun.lockb)
+  @lockfiles ~w(npm.lock package-lock.json pnpm-lock.yaml yarn.lock bun.lock bun.lockb)
 
   defp lockfile_signature(module_dirs) do
     module_dirs
@@ -628,20 +715,27 @@ defmodule Volt.JS.Vendor do
     |> Enum.flat_map(&lockfiles_in/1)
   end
 
-  defp lockfile_roots([]), do: [File.cwd!()]
+  defp lockfile_roots([]), do: [Volt.Paths.root()]
 
   defp lockfile_roots(module_dirs) do
     module_dirs
     |> Enum.map(&Path.dirname/1)
-    |> Kernel.++([File.cwd!()])
+    |> Kernel.++([Volt.Paths.root()])
     |> Enum.uniq()
   end
 
+  # Package managers write lockfiles, which can run to megabytes, so their
+  # size and modification time stand in for their contents. The hash is
+  # computed on every vendor import and every request of a compiled module.
   defp lockfiles_in(root) do
-    @lockfiles
-    |> Enum.map(&Path.join(root, &1))
-    |> Enum.filter(&File.regular?/1)
-    |> Enum.map(&{&1, file_signature(&1)})
+    Enum.flat_map(@lockfiles, fn name ->
+      path = Path.join(root, name)
+
+      case File.stat(path, time: :posix) do
+        {:ok, %File.Stat{type: :regular, size: size, mtime: mtime}} -> [{path, size, mtime}]
+        _other -> []
+      end
+    end)
   end
 
   defp file_signature(path) do
@@ -651,11 +745,15 @@ defmodule Volt.JS.Vendor do
     end
   end
 
-  defp cache_path(specifier) do
-    Path.join(cache_dir(), encode_specifier(specifier) <> ".js")
+  defp cache_path(specifier, module_dirs, plugins, module_types) do
+    Path.join(
+      context_dir(module_dirs, plugins, module_types),
+      encode_specifier(specifier) <> ".js"
+    )
   end
 
-  defp cache_meta_path(specifier), do: cache_path(specifier) <> ".meta"
+  defp cache_meta_path(specifier, module_dirs, plugins, module_types),
+    do: cache_path(specifier, module_dirs, plugins, module_types) <> ".meta"
 
   @doc "Encode a specifier for use in URLs (escaping @ and /)."
   def encode_specifier(specifier) do
diff --git a/lib/volt/npm.ex b/lib/volt/npm.ex
new file mode 100644
index 0000000..753efc2
--- /dev/null
+++ b/lib/volt/npm.ex
@@ -0,0 +1,36 @@
+defmodule Volt.NPM do
+  @moduledoc """
+  Installs exact npm package sets into Volt's isolated, npm_ex-backed cache.
+
+  Frameworks and plugins can use this API for JavaScript dependencies they own
+  without adding those packages to an application's `node_modules` directory.
+  The returned directory is stable for the normalized package set and can be
+  passed to `Volt.Builder` as a package directory or scoped package root.
+
+  Pass a package-owned npm_ex lockfile to make fresh installs consume its exact
+  transitive graph without contacting the registry resolver:
+
+      Volt.NPM.install!(packages, lockfile: Volt.Priv.path(:my_app, "npm.lock"))
+
+  The lockfile must use npm_ex lockfile version 1, match the current security
+  policy, and contain every direct package at its declared exact version.
+  """
+
+  @type install_result :: %{install_dir: String.t(), node_modules: String.t()}
+
+  @doc "Install a package map and return its isolated cache directories."
+  @spec install!(%{String.t() => String.t()}, keyword()) :: install_result()
+  def install!(packages, opts \\ []) when is_map(packages) do
+    Enum.each(packages, fn
+      {name, version}
+      when is_binary(name) and name != "" and is_binary(version) and version != "" ->
+        :ok
+
+      package ->
+        raise ArgumentError,
+              "expected npm packages to contain non-empty string names and versions, got: #{inspect(package)}"
+    end)
+
+    Volt.JS.Runtime.Installer.install!(packages, opts)
+  end
+end
diff --git a/lib/volt/paths.ex b/lib/volt/paths.ex
index 0d5c72d..6e2c20d 100644
--- a/lib/volt/paths.ex
+++ b/lib/volt/paths.ex
@@ -17,6 +17,28 @@ defmodule Volt.Paths do
     def unquote(name)(), do: unquote(value)
   end
 
+  @root {__MODULE__, :root}
+
+  @doc """
+  Remember the working directory as the project root. Called when Volt starts.
+
+  The working directory belongs to the whole VM, and Mix changes it while it
+  compiles a dependency, as `Phoenix.CodeReloader` does for a reloadable path
+  dependency during a request. A relative path resolved in that window lands in
+  the dependency's directory, so the development server resolves paths from the
+  root captured here instead.
+  """
+  @spec capture_root() :: :ok
+  def capture_root, do: :persistent_term.put(@root, File.cwd!())
+
+  @doc "The project root: the working directory when Volt started, or the current one."
+  @spec root() :: String.t()
+  def root, do: :persistent_term.get(@root, nil) || File.cwd!()
+
+  @doc "Expand a path from the project root."
+  @spec expand(String.t()) :: String.t()
+  def expand(path), do: Path.expand(path, root())
+
   def ignored_dirs, do: @ignored_dirs
   def ignored_globs, do: Enum.map(@ignored_dirs, &"#{&1}/**")
 end
diff --git a/lib/volt/pipeline.ex b/lib/volt/pipeline.ex
index 5637125..7460b8d 100644
--- a/lib/volt/pipeline.ex
+++ b/lib/volt/pipeline.ex
@@ -50,7 +50,7 @@ defmodule Volt.Pipeline do
         Volt.MIME.css?(content_type) ->
           compile_css(compile_path, source, opts)
 
-        ext in Volt.JS.Extensions.js() ->
+        ext in Volt.JS.Extensions.bundleable() ->
           compile_js(compile_path, source, opts)
 
         Volt.CSS.Modules.css_module?(base_path) ->
diff --git a/lib/volt/plugin.ex b/lib/volt/plugin.ex
index 0c1f1aa..2d698ee 100644
--- a/lib/volt/plugin.ex
+++ b/lib/volt/plugin.ex
@@ -53,6 +53,17 @@ defmodule Volt.Plugin do
               [Volt.Plugin.EmbeddedModule.t() | {extension :: String.t(), source :: String.t()}]
               | nil
 
+  @doc """
+  Return the TypeScript declaration of a plugin-owned source file, as the
+  type checker should see the module it exports.
+
+  `mix volt.js.check` resolves imports of the file to the declaration, named
+  `<file>.d.ts`, in place of a `declare module "*.ext"` shim. Return `nil`
+  for files the plugin has no declaration for.
+  """
+  @callback declaration(path :: String.t(), source :: String.t(), opts :: keyword()) ::
+              {:ok, String.t()} | {:error, term()} | nil
+
   @doc "Transform compiled JavaScript before serving or bundling."
   @callback transform(code :: String.t(), path :: String.t()) :: {:ok, String.t()} | nil
 
@@ -102,6 +113,7 @@ defmodule Volt.Plugin do
                       compile: 3,
                       extract_imports: 3,
                       embedded_modules: 3,
+                      declaration: 3,
                       transform: 2,
                       define: 1,
                       prebundle_alias: 1,
diff --git a/lib/volt/plugin/solid.ex b/lib/volt/plugin/solid.ex
index 509d06c..91162f8 100644
--- a/lib/volt/plugin/solid.ex
+++ b/lib/volt/plugin/solid.ex
@@ -11,10 +11,13 @@ defmodule Volt.Plugin.Solid do
 
   @behaviour Volt.Plugin
 
+  alias Volt.JS.Runtime.PackageSet
+
   @runtime_packages %{
-    "@babel/standalone" => "^7.0.0",
-    "babel-preset-solid" => "^1.9.0"
+    "@babel/standalone" => "7.29.8",
+    "babel-preset-solid" => "1.9.12"
   }
+  @runtime_package_set PackageSet.bundled(:volt, :solid, @runtime_packages)
 
   @runtime_name __MODULE__.Runtime
   @jsx_exts ~w(.jsx .tsx)
@@ -61,12 +64,13 @@ defmodule Volt.Plugin.Solid do
   def prebundle_entry(_specifier), do: nil
 
   def runtime_packages, do: @runtime_packages
+  def runtime_package_set, do: @runtime_package_set
 
   defp do_compile(source, filename, opts, plugin_opts) do
     runtime =
-      Volt.JS.Runtime.ensure!(
+      PackageSet.runtime_opts(
+        @runtime_package_set,
         name: @runtime_name,
-        packages: @runtime_packages,
         apis: [:browser, :node],
         entry: {:volt_asset, "compilers/solid.ts"},
         bundle: true,
@@ -75,6 +79,7 @@ defmodule Volt.Plugin.Solid do
         ],
         max_stack_size: 32 * 1024 * 1024
       )
+      |> Volt.JS.Runtime.ensure!()
 
     compile_options =
       filename
diff --git a/lib/volt/plugin/svelte.ex b/lib/volt/plugin/svelte.ex
index a5e8cbe..d3d5cb2 100644
--- a/lib/volt/plugin/svelte.ex
+++ b/lib/volt/plugin/svelte.ex
@@ -5,7 +5,10 @@ defmodule Volt.Plugin.Svelte do
 
   @behaviour Volt.Plugin
 
-  @runtime_packages %{"svelte" => "^5.0.0"}
+  alias Volt.JS.Runtime.PackageSet
+
+  @runtime_packages %{"svelte" => "5.56.8"}
+  @runtime_package_set PackageSet.bundled(:volt, :svelte, @runtime_packages)
   @runtime_name __MODULE__.Runtime
   @resolve_extensions Volt.JS.Extensions.node_resolvable()
 
@@ -37,7 +40,7 @@ defmodule Volt.Plugin.Svelte do
   def resolve(_, _), do: nil
 
   defp resolve_svelte(specifier, _importer) do
-    install = Volt.JS.Runtime.Installer.install!(@runtime_packages)
+    install = PackageSet.install!(@runtime_package_set)
 
     case NPM.Resolution.PackageResolver.resolve(specifier, install.install_dir,
            extensions: @resolve_extensions,
@@ -77,17 +80,19 @@ defmodule Volt.Plugin.Svelte do
   end
 
   def runtime_packages, do: @runtime_packages
+  def runtime_package_set, do: @runtime_package_set
 
   defp do_compile(path, source, opts, plugin_opts) do
     runtime =
-      Volt.JS.Runtime.ensure!(
+      PackageSet.runtime_opts(
+        @runtime_package_set,
         name: @runtime_name,
-        packages: @runtime_packages,
         apis: [:browser, :node],
         entry: {:volt_asset, "compilers/svelte.ts"},
         bundle: true,
         max_stack_size: 16 * 1024 * 1024
       )
+      |> Volt.JS.Runtime.ensure!()
 
     compile_options =
       path
diff --git a/lib/volt/plugin/vue.ex b/lib/volt/plugin/vue.ex
index 6aa5872..00b36fe 100644
--- a/lib/volt/plugin/vue.ex
+++ b/lib/volt/plugin/vue.ex
@@ -1,6 +1,8 @@
 defmodule Volt.Plugin.Vue do
   @behaviour Volt.Plugin
 
+  alias Vize.SFC
+
   @impl true
   def name, do: "vue"
 
@@ -22,41 +24,86 @@ defmodule Volt.Plugin.Vue do
     {base_path, query} = Volt.URL.split_query(path)
 
     if query == "" and Path.extname(base_path) == ".vue" do
+      scope_id = SFC.scope_id(base_path)
+
       sfc_opts = [
-        filename: Path.basename(path),
+        scope_id: scope_id,
+        filename: base_path,
         vapor: Keyword.get(opts, :vapor, false),
         strip_types: true,
-        custom_renderer: Keyword.get(opts, :custom_renderer, false)
+        custom_renderer: Keyword.get(opts, :custom_renderer, false),
+        source_map: Keyword.get(opts, :sourcemap, true)
       ]
 
-      case Vize.compile_sfc(source, sfc_opts) do
-        {:ok, result} ->
-          {:ok,
-           %Volt.Pipeline.Result{
-             code: maybe_append_style_imports(result.code, path, source, opts),
-             sourcemap: nil,
-             css: result.css,
-             hashes: %Volt.Pipeline.Result.Hashes{
-               template: result.template_hash,
-               style: result.style_hash,
-               script: result.script_hash
-             }
-           }}
-
-        {:error, reason} ->
-          {:error, reason}
+      with {:ok, descriptor} <- Vize.parse_sfc(source),
+           {:ok, assets} <- SFC.collect_template_assets(source, filename: base_path),
+           {:ok, result} <- Vize.compile_sfc(source, sfc_opts) do
+        assembled =
+          result.code
+          |> assemble_template_component(descriptor, sfc_opts[:vapor])
+          |> attach_scope(descriptor, scope_id, sfc_opts[:vapor])
+
+        {:ok,
+         %Volt.Pipeline.Result{
+           code:
+             assembled
+             |> SFC.rewrite_asset_references(assets)
+             |> append_template_asset_imports(assets)
+             |> maybe_append_style_imports(path, source, opts),
+           sourcemap: if(assembled == result.code, do: result.source_map),
+           css: result.css,
+           hashes: %Volt.Pipeline.Result.Hashes{
+             template: result.template_hash,
+             style: result.style_hash,
+             script: result.script_hash
+           }
+         }}
       end
     end
   end
 
+  defp assemble_template_component(
+         code,
+         %{script: nil, script_setup: nil, template: template},
+         false
+       )
+       when not is_nil(template), do: code <> "\nexport default { render };\n"
+
+  defp assemble_template_component(code, _descriptor, _vapor), do: code
+
+  defp attach_scope(code, %{styles: styles}, scope_id, false) do
+    if Enum.any?(styles, & &1.scoped) do
+      {:ok, %{body: nodes}} = OXC.parse(code, "component.js")
+
+      patches =
+        for %{type: :export_default_declaration, declaration: declaration} <- nodes do
+          %{start: first, end: last} = declaration
+          expression = binary_part(code, first, last - first)
+
+          value =
+            "((component) => { component.__scopeId = #{Jason.encode!("data-v-" <> scope_id)}; return component; })(#{expression})"
+
+          Volt.JS.Patch.new(first, last, value)
+        end
+
+      Volt.JS.Patch.apply(code, patches)
+    else
+      code
+    end
+  end
+
+  defp attach_scope(code, _descriptor, _scope_id, _vapor), do: code
+
   @impl true
   def extract_imports(path, source, _opts) do
     if Path.extname(path) == ".vue" do
-      {:ok,
-       %Volt.JS.ImportExtractor.Result{
-         imports: source |> imports() |> Enum.map(&{:static, &1}),
-         workers: []
-       }}
+      with {:ok, assets} <- Vize.SFC.collect_template_assets(source, filename: path) do
+        {:ok,
+         %Volt.JS.ImportExtractor.Result{
+           imports: source |> imports(assets) |> Enum.map(&{:static, &1}),
+           workers: []
+         }}
+      end
     end
   end
 
@@ -69,6 +116,17 @@ defmodule Volt.Plugin.Vue do
     end
   end
 
+  @impl true
+  def declaration(path, source, _opts) do
+    {base_path, _query} = Volt.URL.split_query(path)
+
+    if Path.extname(base_path) == ".vue" do
+      with {:ok, %{dts: dts}} <- Vize.generate_dts(source, filename: Path.basename(base_path)) do
+        {:ok, dts}
+      end
+    end
+  end
+
   defp maybe_append_style_imports(code, path, source, opts) do
     if Keyword.get(opts, :mode) == :development do
       style_imports =
@@ -84,6 +142,20 @@ defmodule Volt.Plugin.Vue do
     end
   end
 
+  defp append_template_asset_imports(code, assets) do
+    imports = Enum.map(assets, &template_asset_import/1)
+    IO.iodata_to_binary([code | imports])
+  end
+
+  defp template_asset_import(asset) do
+    "import $name from \"__specifier__\";"
+    |> OXC.parse!("vue-template-asset-import.ts")
+    |> OXC.bind(name: asset.binding)
+    |> Volt.JS.AST.replace_literal("__specifier__", asset_specifier(asset))
+    |> OXC.codegen!()
+    |> then(&["\n", String.trim(&1)])
+  end
+
   defp style_import(path, module) do
     specifier = Volt.Plugin.EmbeddedModule.specifier(path, module)
 
@@ -94,14 +166,22 @@ defmodule Volt.Plugin.Vue do
     |> then(&["\n", String.trim(&1)])
   end
 
-  defp imports(source), do: source |> scripts() |> Enum.flat_map(&script_imports/1)
+  defp imports(source, assets) do
+    script_imports = source |> scripts() |> Enum.flat_map(&script_imports/1)
+    script_imports ++ Enum.map(assets, &asset_specifier/1)
+  end
+
+  defp asset_specifier(asset), do: asset.url |> String.split("#", parts: 2) |> hd()
 
   defp scripts(source) do
     case Vize.parse_sfc(source) do
       {:ok, descriptor} ->
-        [descriptor.script, descriptor.script_setup]
-        |> Enum.reject(&is_nil/1)
-        |> Enum.map(fn block -> {script_extension(block[:lang]), block.content} end)
+        # A block in another language, such as `<script lang="elixir">`, belongs
+        # to other tooling and is not a JavaScript module.
+        for block <- [descriptor.script, descriptor.script_setup],
+            block != nil,
+            extension = script_extension(block[:lang]),
+            do: {extension, block.content}
 
       {:error, _} ->
         []
@@ -132,9 +212,11 @@ defmodule Volt.Plugin.Vue do
     end
   end
 
+  defp script_extension(lang) when lang in [nil, "js"], do: ".js"
+  defp script_extension("jsx"), do: ".jsx"
   defp script_extension("ts"), do: ".ts"
   defp script_extension("tsx"), do: ".tsx"
-  defp script_extension(_lang), do: ".js"
+  defp script_extension(_lang), do: nil
 
   defp style_extension(lang) when lang in [nil, "css"], do: ".css"
   defp style_extension(lang), do: ".#{lang}"
diff --git a/lib/volt/plugin_runner.ex b/lib/volt/plugin_runner.ex
index e60f05f..3a35b8a 100644
--- a/lib/volt/plugin_runner.ex
+++ b/lib/volt/plugin_runner.ex
@@ -74,6 +74,15 @@ defmodule Volt.PluginRunner do
     |> Volt.Plugin.EmbeddedModule.normalize_all()
   end
 
+  @doc "The declaration of a plugin-owned source file, from the first plugin that has one."
+  @spec declaration([module() | {module(), keyword()}], String.t(), String.t(), keyword()) ::
+          {:ok, String.t()} | {:error, term()} | nil
+  def declaration(plugins, path, source, opts) do
+    plugins
+    |> plugins()
+    |> Enum.find_value(&call_optional(&1, :declaration, [path, source, opts], nil))
+  end
+
   @doc "Load one embedded query module by id."
   @spec embedded_module([module() | {module(), keyword()}], String.t(), keyword()) ::
           {:ok, Volt.Plugin.EmbeddedModule.t(), String.t()} | {:error, term()} | nil
diff --git a/lib/volt/preload.ex b/lib/volt/preload.ex
index fc1b4b5..0e908b3 100644
--- a/lib/volt/preload.ex
+++ b/lib/volt/preload.ex
@@ -63,8 +63,14 @@ defmodule Volt.Preload do
     chunk
     |> Map.get("imports", [])
     |> Enum.reject(&MapSet.member?(seen, &1))
-    |> Enum.flat_map(fn file ->
-      [file | imported_files(manifest, manifest[file] || %{}, MapSet.put(seen, file))]
+    |> Enum.flat_map(fn key ->
+      case Map.get(manifest, key) do
+        %{"file" => file} = imported ->
+          [file | imported_files(manifest, imported, MapSet.put(seen, key))]
+
+        _ ->
+          []
+      end
     end)
     |> js_files()
   end
diff --git a/lib/volt/priv.ex b/lib/volt/priv.ex
index a2c8097..c1710bd 100644
--- a/lib/volt/priv.ex
+++ b/lib/volt/priv.ex
@@ -15,14 +15,25 @@ defmodule Volt.Priv do
 
       Volt.Priv.path(assets, "runtime.ts")
       Volt.Priv.read!(assets, "runtime.ts")
+      Volt.Priv.render!(assets, "entry.ts", [], splices: [body: "start();"])
       Volt.Priv.js!(assets, "runtime.ts")
       Volt.Priv.js!(assets, "entry.ts", id: "counter", props: %{count: 1})
 
-  `js!/3` binds `$placeholder` JavaScript literals with OXC before emitting browser
-  JavaScript. That keeps templates valid TypeScript or JavaScript files instead of
-  requiring EEx for ordinary data injection.
+  `render!/4` binds and splices templates while preserving TypeScript for a later
+  Volt build. `js!/3` and `js!/4` additionally compile the rendered source to browser
+  JavaScript. This keeps templates valid TypeScript or JavaScript files instead of
+  requiring EEx or textual source replacement.
+
+  `bundle!/3` bundles an entry with everything it imports into one module. npm
+  packages it imports are vendored beside the sources with `mix volt.priv.vendor`
+  (see `Volt.Priv.Vendor`), so they ship in the package and no install happens at
+  runtime:
+
+      Volt.Priv.bundle!(assets, "widget.ts", format: :esm)
   """
 
+  require Logger
+
   @type source :: atom() | {atom(), String.t()}
   @type bindings :: keyword() | map()
 
@@ -47,6 +58,66 @@ defmodule Volt.Priv do
     |> File.read!()
   end
 
+  @doc """
+  Renders a JavaScript or TypeScript template stored under `priv`.
+
+  Literal bindings use `OXC.bind/2`, while the `:splices` option accepts statement,
+  property, and array-element replacements handled by `OXC.splice/3`. The rendered
+  source is not compiled, making this API suitable for virtual modules and generated
+  entries that will subsequently pass through `Volt.Builder`.
+  """
+  @spec render!(source(), String.t()) :: String.t()
+  @spec render!(source(), String.t(), bindings()) :: String.t()
+  @spec render!(source(), String.t(), bindings(), keyword()) :: String.t()
+  def render!(source, relative, bindings \\ [], opts \\ []) when is_binary(relative) do
+    source
+    |> render_source(relative, bindings, Keyword.get(opts, :splices, []))
+    |> rewrite_specifiers(opts[:rewrite_specifiers], relative)
+  end
+
+  @doc """
+  Bundles an entry under `priv` with the modules it imports, including npm packages
+  vendored beside it with `mix volt.priv.vendor`.
+
+  Options are passed to `OXC.bundle/2`, such as `:format` and `:define`.
+  """
+  @spec bundle(source(), String.t(), keyword()) :: {:ok, String.t()} | {:error, term()}
+  def bundle(source, relative, opts \\ []) when is_binary(relative) do
+    entry = path(source, relative)
+    entry |> vendor_root() |> ensure_vendored()
+    Volt.JS.Runtime.Bundler.bundle_file(entry, opts)
+  end
+
+  # The nearest directory above the entry with a vendoring `package.json`.
+  defp vendor_root(entry) do
+    entry
+    |> Path.dirname()
+    |> Stream.iterate(&Path.dirname/1)
+    |> Enum.take_while(&(Path.basename(&1) != "priv"))
+    |> Enum.find(&File.regular?(Path.join(&1, "package.json")))
+  end
+
+  # Git and path checkouts have no vendored files, so vendor them on first use.
+  defp ensure_vendored(nil), do: :ok
+
+  defp ensure_vendored(dir) do
+    unless File.dir?(Path.join(dir, "node_modules")) do
+      Logger.info("[Volt] Vendoring npm packages for #{dir}")
+      Volt.Priv.Vendor.run!(dir)
+    end
+
+    :ok
+  end
+
+  @doc "Like `bundle/3`, but raises when the entry cannot be bundled."
+  @spec bundle!(source(), String.t(), keyword()) :: String.t()
+  def bundle!(source, relative, opts \\ []) do
+    case bundle(source, relative, opts) do
+      {:ok, code} -> code
+      {:error, reason} -> raise "could not bundle #{relative}: #{inspect(reason)}"
+    end
+  end
+
   @doc """
   Emits browser JavaScript for a support file stored under `priv`.
 
@@ -56,6 +127,8 @@ defmodule Volt.Priv do
 
   Options:
 
+    * `:splices` - a keyword list of `$placeholder` names to statement,
+      property, or array-element replacements accepted by `OXC.splice/3`.
     * `:rewrite_specifiers` - a map or keyword list of import specifiers to rewrite
       after code generation.
   """
@@ -64,43 +137,68 @@ defmodule Volt.Priv do
   @spec js!(source(), String.t(), bindings(), keyword()) :: String.t()
   def js!(source, relative, bindings \\ [], opts \\ []) when is_binary(relative) do
     source
-    |> js_source(relative, bindings)
+    |> js_source(relative, bindings, Keyword.get(opts, :splices, []))
     |> rewrite_specifiers(opts[:rewrite_specifiers], relative)
   end
 
-  defp js_source(source, relative, bindings) when bindings == [] or bindings == %{} do
-    key = {__MODULE__, :js, source, relative}
+  defp js_source(source, relative, bindings, splices) do
+    if empty?(bindings) and empty?(splices) do
+      cached_js!(source, relative)
+    else
+      source
+      |> render_source(relative, bindings, splices)
+      |> compile(relative)
+    end
+  end
 
-    case :persistent_term.get(key, nil) do
-      nil ->
-        code = source |> read!(relative) |> compile(relative)
-        :persistent_term.put(key, code)
-        code
+  defp render_source(source, relative, bindings, splices) do
+    cond do
+      empty?(bindings) and empty?(splices) ->
+        read!(source, relative)
+
+      empty?(bindings) ->
+        source
+        |> read!(relative)
+        |> OXC.parse!(relative, :native)
+        |> splice_all(splices)
+        |> OXC.codegen!()
 
-      code ->
-        code
+      true ->
+        source
+        |> template_ast!(relative)
+        |> OXC.bind(literal_bindings(bindings))
+        |> splice_all(splices)
+        |> OXC.codegen!()
     end
   end
 
-  defp js_source(source, relative, bindings) do
-    source
-    |> template_ast!(relative)
-    |> OXC.bind(literal_bindings(bindings))
-    |> OXC.codegen!()
-    |> compile(relative)
+  defp cached_js!(source, relative) do
+    source_code = read!(source, relative)
+
+    cached_value({__MODULE__, :js, source, relative}, source_code, fn ->
+      compile(source_code, relative)
+    end)
   end
 
   defp template_ast!(source, relative) do
-    key = {__MODULE__, :template_ast, source, relative}
+    source_code = read!(source, relative)
+
+    cached_value({__MODULE__, :template_ast, source, relative}, source_code, fn ->
+      OXC.parse!(source_code, relative)
+    end)
+  end
+
+  defp cached_value(key, source, build) do
+    fingerprint = {byte_size(source), :erlang.phash2(source)}
 
     case :persistent_term.get(key, nil) do
-      nil ->
-        ast = source |> read!(relative) |> OXC.parse!(relative)
-        :persistent_term.put(key, ast)
-        ast
+      {^fingerprint, value} ->
+        value
 
-      ast ->
-        ast
+      _stale_or_missing ->
+        value = build.()
+        :persistent_term.put(key, {fingerprint, value})
+        value
     end
   end
 
@@ -108,6 +206,14 @@ defmodule Volt.Priv do
     Enum.map(bindings, fn {key, value} -> {key, {:literal, value}} end)
   end
 
+  defp splice_all(ast, splices) do
+    Enum.reduce(splices, ast, fn {name, replacement}, acc ->
+      OXC.splice(acc, name, replacement)
+    end)
+  end
+
+  defp empty?(value), do: value == [] or value == %{}
+
   defp rewrite_specifiers(code, nil, _filename), do: code
   defp rewrite_specifiers(code, [], _filename), do: code
 
diff --git a/lib/volt/priv/vendor.ex b/lib/volt/priv/vendor.ex
new file mode 100644
index 0000000..a8fc7d4
--- /dev/null
+++ b/lib/volt/priv/vendor.ex
@@ -0,0 +1,225 @@
+defmodule Volt.Priv.Vendor do
+  @moduledoc """
+  Vendors npm packages for browser code kept under `priv`.
+
+  List the packages in a `package.json` beside the sources, pinned to exact
+  versions, and commit it with the `npm.lock` that vendoring writes:
+
+  ```json
+  {"private": true, "dependencies": {"lit-html": "3.3.3"}}
+  ```
+
+  `mix volt.priv.vendor priv/ts` installs the locked versions and writes only the
+  files the sources reach to `node_modules` beside them: the browser build of every
+  imported module, the type declarations behind it, and each package's
+  `package.json` and license. Keep that directory out of git and vendor before
+  publishing, so the files ship in the Hex package and nothing is installed at
+  runtime.
+
+  `Volt.Priv.bundle!/3` resolves imports such as `import { html } from 'lit-html'`
+  from there, and vendors on first use when the directory is missing, as in a git
+  checkout.
+  """
+
+  alias NPM.Resolution.PackageResolver
+
+  @source_extensions ~w(.ts .tsx .mts .js .jsx .mjs)
+  @type_conditions ["types", "import", "default"]
+
+  @doc """
+  Vendors the packages that `dir/package.json` lists into `dir/node_modules`.
+
+  ## Options
+
+    * `:update` — resolve the versions again instead of using `dir/npm.lock`
+  """
+  @spec run!(Path.t(), keyword()) :: [Path.t()]
+  def run!(dir, opts \\ []) do
+    with_install(dir, opts, fn install_dir, files ->
+      node_modules = Path.join(dir, "node_modules")
+      File.rm_rf!(node_modules)
+
+      for file <- files do
+        target = Path.join(node_modules, file)
+        File.mkdir_p!(Path.dirname(target))
+        File.cp!(Path.join([install_dir, "node_modules", file]), target)
+      end
+
+      File.cp!(Path.join(install_dir, "npm.lock"), Path.join(dir, "npm.lock"))
+      files
+    end)
+  end
+
+  defp with_install(dir, opts, fun) do
+    packages = dir |> Path.join("package.json") |> File.read!() |> Jason.decode!()
+    packages = Map.get(packages, "dependencies", %{})
+    lockfile = Path.join(dir, "npm.lock")
+
+    install_dir =
+      Path.join(System.tmp_dir!(), "volt-vendor-#{System.unique_integer([:positive])}")
+
+    try do
+      Volt.JS.Runtime.Installer.install!(packages,
+        install_dir: install_dir,
+        lockfile:
+          if(File.regular?(lockfile) and not Keyword.get(opts, :update, false), do: lockfile)
+      )
+
+      fun.(install_dir, reachable(dir, packages, Path.join(install_dir, "node_modules")))
+    after
+      File.rm_rf!(install_dir)
+    end
+  end
+
+  @doc false
+  # The files the sources in `dir` reach in `node_modules`, relative to it.
+  @spec reachable(Path.t(), map(), Path.t()) :: [Path.t()]
+  def reachable(dir, packages, node_modules) do
+    roots =
+      for source <- sources(dir),
+          specifier <- imports(source),
+          Map.has_key?(packages, package_name(specifier)),
+          kind <- [:js, :types],
+          do: {kind, specifier, node_modules}
+
+    roots
+    |> walk(MapSet.new())
+    |> Enum.flat_map(&[&1 | package_files(&1, node_modules)])
+    |> Enum.uniq()
+    |> Enum.map(&Path.relative_to(&1, node_modules))
+    |> Enum.sort()
+  end
+
+  defp walk([], seen), do: seen
+
+  defp walk([{kind, specifier, from} | rest], seen) do
+    case resolve(kind, specifier, from) do
+      {:ok, path} ->
+        if MapSet.member?(seen, path) do
+          walk(rest, seen)
+        else
+          next = for import <- imports(path), do: {kind, import, Path.dirname(path)}
+          walk(next ++ rest, MapSet.put(seen, path))
+        end
+
+      :error ->
+        walk(rest, seen)
+    end
+  end
+
+  defp resolve(:js, specifier, from) do
+    specifier
+    |> PackageResolver.resolve(from,
+      conditions: Volt.JS.Resolution.browser_conditions(),
+      extensions: Volt.JS.Extensions.node_resolvable()
+    )
+    |> file_result()
+  end
+
+  # TypeScript's own lookup: a `types` export or a declaration beside the module,
+  # the package's `types` field, then the same path under `@types`.
+  defp resolve(:types, specifier, from) do
+    with :error <- declaration(specifier, from),
+         :error <- package_types(specifier, from),
+         false <- relative?(specifier) or String.starts_with?(specifier, "@types/") do
+      resolve(:types, types_specifier(specifier), from)
+    else
+      true -> :error
+      found -> found
+    end
+  end
+
+  # Declarations drop the module extension: `lib/index.js` is typed by `lib/index.d.ts`.
+  defp declaration(specifier, from) do
+    Enum.find_value([specifier, Path.rootname(specifier, Path.extname(specifier))], :error, fn
+      specifier ->
+        with {:ok, path} <-
+               specifier
+               |> PackageResolver.resolve(from,
+                 conditions: @type_conditions,
+                 extensions: [".d.ts"]
+               )
+               |> file_result(),
+             {:ok, declaration} <- declaration_for(path) do
+          {:ok, declaration}
+        else
+          _ -> nil
+        end
+    end)
+  end
+
+  defp file_result({:ok, path}), do: {:ok, path}
+  defp file_result(_other), do: :error
+
+  defp declaration_for(path) do
+    declaration =
+      if String.ends_with?(path, ".d.ts"),
+        do: path,
+        else: Path.rootname(path) <> ".d.ts"
+
+    if File.regular?(declaration), do: {:ok, declaration}, else: :error
+  end
+
+  # A package's `types` field describes its root only.
+  defp package_types(specifier, from) do
+    with true <- not relative?(specifier) and package_name(specifier) == specifier,
+         {:ok, package_dir} <- package_dir(specifier, from),
+         {:ok, json} <- File.read(Path.join(package_dir, "package.json")),
+         %{} = package <- Jason.decode!(json),
+         types when is_binary(types) <- package["types"] || package["typings"] do
+      declaration_for(Path.join(package_dir, types))
+    else
+      _ -> :error
+    end
+  end
+
+  defp package_dir(name, from) do
+    case PackageResolver.find_node_modules(from) do
+      nil -> :error
+      node_modules -> {:ok, Path.join(node_modules, name)}
+    end
+  end
+
+  # Each reached package also keeps its `package.json` and license files.
+  defp package_files(path, node_modules) do
+    package_dir =
+      Path.join(node_modules, path |> Path.relative_to(node_modules) |> package_name())
+
+    Path.wildcard(Path.join(package_dir, "{package.json,LICENSE*,license*}"))
+  end
+
+  defp sources(dir) do
+    dir
+    |> Path.join("**/*")
+    |> Path.wildcard()
+    |> Enum.reject(&String.contains?(Path.relative_to(&1, dir), "node_modules"))
+    |> Enum.filter(&(Path.extname(&1) in @source_extensions))
+  end
+
+  # Import sources, including type-only imports, re-exports, and `import()` types.
+  defp imports(path) do
+    with {:ok, source} <- File.read(path),
+         {:ok, ast} <- OXC.parse(source, Path.basename(path)) do
+      OXC.collect(ast, fn
+        %{source: %{value: specifier}} when is_binary(specifier) -> {:keep, specifier}
+        _node -> :skip
+      end)
+    else
+      _ -> []
+    end
+  end
+
+  defp relative?(specifier), do: String.starts_with?(specifier, [".", "/"])
+
+  defp package_name("@" <> _ = specifier),
+    do: specifier |> String.split("/") |> Enum.take(2) |> Enum.join("/")
+
+  defp package_name(specifier), do: specifier |> String.split("/", parts: 2) |> hd()
+
+  # `@scope/pkg/sub` is typed by `@types/scope__pkg/sub`, `pkg/sub` by `@types/pkg/sub`.
+  defp types_specifier(specifier) do
+    name = package_name(specifier)
+    subpath = String.replace_prefix(specifier, name, "")
+    "@types/" <> String.replace(String.trim_leading(name, "@"), "/", "__") <> subpath
+  end
+end
diff --git a/lib/volt/public_dir.ex b/lib/volt/public_dir.ex
index 0415c49..3846a27 100644
--- a/lib/volt/public_dir.ex
+++ b/lib/volt/public_dir.ex
@@ -16,7 +16,7 @@ defmodule Volt.PublicDir do
   @spec resolve(String.t() | false | nil) :: String.t() | nil
   def resolve(false), do: nil
   def resolve(nil), do: nil
-  def resolve(path), do: Path.expand(path)
+  def resolve(path), do: Volt.Paths.expand(path)
 
   @doc """
   Copies all files from `public_dir` into `static_root`.
@@ -37,6 +37,44 @@ defmodule Volt.PublicDir do
     :ok
   end
 
+  @doc "Read public files into artifacts relative to the static root without copying them."
+  def prepare(nil), do: []
+
+  def prepare(public_dir) do
+    if File.dir?(public_dir) do
+      Enum.map(files(public_dir), fn path ->
+        %Volt.Builder.Artifact{
+          file: Path.relative_to(path, public_dir),
+          content: File.read!(path)
+        }
+      end)
+    else
+      []
+    end
+  end
+
+  @doc "Combine asset output and public files in a validated static-root plan."
+  def prepare_output(plan, outdir, public_dir, publication_root) do
+    outdir = Path.expand(outdir)
+    static_root = Path.expand(publication_root)
+    prefix = Path.relative_to(outdir, static_root)
+
+    if outdir == static_root or Volt.Path.inside?(outdir, static_root) do
+      assets =
+        Enum.map(plan.artifacts, fn artifact ->
+          if prefix == ".",
+            do: artifact,
+            else: %{artifact | file: Path.join(prefix, artifact.file)}
+        end)
+
+      with {:ok, combined} <- Volt.Builder.Plan.new(assets ++ prepare(public_dir)) do
+        {:ok, static_root, combined}
+      end
+    else
+      {:error, {:invalid_publication_root, static_root, outdir}}
+    end
+  end
+
   @doc """
   Resolves a root-relative request path inside `public_dir`.
 
diff --git a/lib/volt/tailwind.ex b/lib/volt/tailwind.ex
index 2339fbc..0166f6c 100644
--- a/lib/volt/tailwind.ex
+++ b/lib/volt/tailwind.ex
@@ -1,197 +1,41 @@
 defmodule Volt.Tailwind do
   @moduledoc """
-  Tailwind CSS integration — scan source files for candidates and compile CSS.
+  Tailwind CSS build contexts backed by Oxide and QuickBEAM.
 
-  Uses Oxide for fast parallel content scanning and QuickBEAM to run
-  the Tailwind CSS compiler. No Node.js or CLI required.
-
-  ## Usage
-
-      # In your config:
-      config :volt, :tailwind,
-        sources: [
-          %{base: "lib/", pattern: "**/*.{ex,heex}"},
-          %{base: "assets/", pattern: "**/*.{vue,ts,tsx}"}
-        ]
-
-      # Generate CSS:
-      {:ok, css} = Volt.Tailwind.build()
-
-  ## Tailwind directives
-
-  Volt supports Tailwind's CSS-first directives like `@theme`, `@source`,
-  `@utility`, `@variant`, and `@apply` through the Tailwind compiler.
-
-  Volt also resolves local `@import`, `@reference`, `@plugin`, and `@config`
-  files inside QuickBEAM, plus installed package plugins like
-  `@tailwindcss/typography`.
+  Each CSS root/profile pair owns an isolated scanner and generated CSS state.
+  This keeps incremental rebuilds independent across applications and profiles.
   """
 
-  use GenServer
-
-  def start_link(opts \\ []) do
-    GenServer.start_link(__MODULE__, opts, name: __MODULE__)
-  end
-
-  @doc """
-  Compile Tailwind CSS from scanned candidates.
-
-  Scans all configured source directories for Tailwind class candidates,
-  then runs the Tailwind compiler to generate CSS.
-
-  ## Options
+  @default_key {:default, :inline}
 
-    * `:css` — custom input CSS (default: Tailwind's base with theme + preflight + utilities)
-    * `:css_base` — base directory for resolving local `@import`, `@reference`, `@plugin`, and `@config` paths
-    * `:sources` — override source patterns (default: from config)
-    * `:minify` — minify the output CSS (default: `false`)
-  """
   @spec build(keyword()) :: {:ok, String.t()} | {:error, term()}
   def build(opts \\ []) do
-    GenServer.call(__MODULE__, {:build, opts}, :infinity)
+    opts
+    |> worker()
+    |> GenServer.call({:build, opts}, :infinity)
   end
 
-  @doc """
-  Incremental build — only process changed files and return CSS if new candidates found.
-
-  Returns `{:ok, css}` if new candidates were found, `:unchanged` otherwise.
-  """
-  @spec rebuild(list(), keyword()) :: {:ok, String.t()} | :unchanged | {:error, term()}
+  @spec rebuild([String.t() | map()], keyword()) ::
+          {:ok, String.t()} | :unchanged | {:error, term()}
   def rebuild(changed_files, opts \\ []) do
-    GenServer.call(__MODULE__, {:rebuild, changed_files, opts}, :infinity)
-  end
-
-  @impl true
-  def init(opts) do
-    sources = opts[:sources] || Volt.Config.tailwind()[:sources] || []
-
-    {:ok,
-     %{
-       runtime: nil,
-       scanner: nil,
-       sources: sources,
-       last_css: nil
-     }}
+    opts
+    |> worker()
+    |> GenServer.call({:rebuild, changed_files, opts}, :infinity)
   end
 
-  defp ensure_runtime(%{runtime: nil} = state) do
-    runtime =
-      Volt.JS.Runtime.ensure!(
-        packages: Volt.Tailwind.Loader.runtime_packages(),
-        apis: [:browser, :node],
-        handlers: fn runtime -> Volt.Tailwind.Loader.handlers(runtime.node_modules) end,
-        define: fn runtime ->
-          %{
-            "TAILWIND_ROOT" => Volt.JS.Runtime.package_path!(runtime, "tailwindcss"),
-            "TAILWIND_DEFAULT_BASE" => File.cwd!()
-          }
-        end,
-        entry: {:volt_asset, "compilers/tailwind.ts"}
-      )
-
-    %{state | runtime: runtime, scanner: build_scanner(state.sources)}
-  end
-
-  defp ensure_runtime(state), do: state
-
-  @impl true
-  def handle_call({:build, opts}, _from, state) do
-    state = ensure_runtime(state)
-    css_input = opts[:css]
-    minify = Keyword.get(opts, :minify, false)
-    css_base = opts[:css_base] || File.cwd!()
-    sources = opts[:sources] || state.sources
-
-    scanner =
-      if(opts[:sources],
-        do: build_scanner(sources),
-        else: state.scanner || Oxide.new(sources: [])
-      )
-
-    case compile_css(state.runtime, css_input, Oxide.scan(scanner), css_base) do
-      {:ok, css} ->
-        css = maybe_minify(css, minify)
-        {:reply, {:ok, css}, %{state | scanner: scanner, last_css: css}}
-
-      {:error, _} = error ->
-        {:reply, error, state}
+  defp worker(opts) do
+    case Keyword.fetch(opts, :worker) do
+      {:ok, worker} -> worker
+      :error -> registered_worker(opts)
     end
   end
 
-  def handle_call({:rebuild, changed_files, opts}, _from, state) do
-    state = ensure_runtime(state)
-    minify = Keyword.get(opts, :minify, false)
-    css_input = opts[:css]
-    css_base = opts[:css_base] || File.cwd!()
-
-    changed =
-      Enum.map(changed_files, fn
-        path when is_binary(path) ->
-          %Oxide.Changed{file: path, extension: Path.extname(path) |> String.trim_leading(".")}
-
-        map ->
-          struct!(Oxide.Changed, map)
-      end)
-
-    case state.scanner do
-      nil ->
-        {:reply, {:error, :no_scanner}, state}
-
-      scanner ->
-        if Oxide.scan_files(scanner, changed) == [] do
-          {:reply, :unchanged, state}
-        else
-          case compile_css(state.runtime, css_input, Oxide.scan(scanner), css_base) do
-            {:ok, css} ->
-              css = maybe_minify(css, minify)
-              {:reply, {:ok, css}, %{state | last_css: css}}
-
-            {:error, _} = error ->
-              {:reply, error, state}
-          end
-        end
-    end
-  end
-
-  @impl true
-  def terminate(_reason, %{runtime: nil}), do: :ok
-
-  def terminate(_reason, %{runtime: runtime}) do
-    Volt.JS.Runtime.stop(runtime)
-    :ok
-  end
-
-  defp build_scanner([]), do: nil
-
-  defp build_scanner(sources) do
-    oxide_sources = Enum.map(sources, &to_oxide_source/1)
-    Oxide.new(sources: oxide_sources)
-  end
-
-  defp compile_css(runtime, css_input, candidates, css_base) do
-    case Volt.JS.Runtime.call(runtime, "compileTailwindCss", [
-           css_input,
-           candidates,
-           Path.expand(css_base)
-         ]) do
-      {:ok, css} when is_binary(css) -> {:ok, css}
-      {:ok, _} -> {:error, :unexpected_result}
-      {:error, _} = error -> error
-    end
-  end
-
-  defp maybe_minify(css, false), do: css
-
-  defp maybe_minify(css, true) do
-    {:ok, %{code: minified}} = Vize.CSS.compile(css, minify: true)
-    minified
-  end
+  defp registered_worker(opts) do
+    key = Keyword.get(opts, :key, @default_key)
 
-  defp to_oxide_source(%{base: base, pattern: pattern} = source) do
-    %Oxide.Source{
-      base: Path.expand(base),
-      pattern: pattern,
-      negated: Map.get(source, :negated, false)
-    }
+    Volt.Tailwind.Supervisor.worker(key,
+      sources: Keyword.get(opts, :sources, []),
+      runtime: Keyword.get(opts, :runtime)
+    )
   end
 end
diff --git a/lib/volt/tailwind/artifact.ex b/lib/volt/tailwind/artifact.ex
new file mode 100644
index 0000000..906791a
--- /dev/null
+++ b/lib/volt/tailwind/artifact.ex
@@ -0,0 +1,21 @@
+defmodule Volt.Tailwind.Artifact do
+  @moduledoc false
+
+  @spec write(String.t() | nil, String.t(), String.t()) :: :ok
+  def write(nil, _name, _css), do: :ok
+
+  def write(outdir, name, css) do
+    File.mkdir_p!(outdir)
+    path = Path.join(outdir, "#{name}.css")
+    temporary = path <> ".#{System.unique_integer([:positive])}.tmp"
+
+    with :ok <- File.write(temporary, css),
+         :ok <- File.rename(temporary, path) do
+      :ok
+    else
+      {:error, reason} ->
+        File.rm(temporary)
+        raise File.Error, reason: reason, action: "write", path: path
+    end
+  end
+end
diff --git a/lib/volt/tailwind/build.ex b/lib/volt/tailwind/build.ex
new file mode 100644
index 0000000..e7801a3
--- /dev/null
+++ b/lib/volt/tailwind/build.ex
@@ -0,0 +1,57 @@
+defmodule Volt.Tailwind.Build do
+  @moduledoc "Builds a configured Tailwind root into a Volt asset result."
+
+  @spec build(Volt.Config.Tailwind.t(), keyword()) ::
+          {:ok, Volt.Builder.Result.t()} | {:error, term()}
+  def build(%Volt.Config.Tailwind{} = root, opts) do
+    with {:ok, result, plan} <- prepare(root, opts),
+         :ok <- Volt.Builder.Writer.write_plan(Keyword.fetch!(opts, :outdir), plan) do
+      {:ok, result}
+    end
+  end
+
+  @doc "Compile a Tailwind root and prepare output without writing assets."
+  @spec prepare(Volt.Config.Tailwind.t(), keyword()) ::
+          {:ok, Volt.Builder.Result.t(), Volt.Builder.Plan.t()} | {:error, term()}
+  def prepare(%Volt.Config.Tailwind{} = root, opts) do
+    with {:ok, css_input} <- read_css(root.css),
+         {:ok, css} <-
+           Volt.Tailwind.Runtime.compile_once(
+             css_input,
+             [],
+             css_base(root.css),
+             %{
+               base: Path.expand(Keyword.get(opts, :root, File.cwd!())),
+               sources: scan_sources(root.sources)
+             }
+           ) do
+      Volt.Builder.Writer.prepare_style_entry(
+        root.name,
+        css,
+        Keyword.fetch!(opts, :outdir),
+        Keyword.get(opts, :hash, true),
+        root.css,
+        minify: Keyword.get(opts, :minify, true),
+        root: Keyword.get(opts, :root, File.cwd!()),
+        asset_url_prefix: Keyword.get(opts, :asset_url_prefix, Volt.Paths.prefix())
+      )
+    end
+  end
+
+  defp scan_sources(sources) do
+    sources
+    |> Enum.map(fn source ->
+      %{
+        base: Path.expand(source.base),
+        pattern: source.pattern,
+        negated: Map.get(source, :negated, false)
+      }
+    end)
+  end
+
+  defp read_css(nil), do: {:ok, nil}
+  defp read_css(path), do: File.read(path)
+
+  defp css_base(nil), do: File.cwd!()
+  defp css_base(path), do: Path.dirname(path)
+end
diff --git a/lib/volt/tailwind/compilation.ex b/lib/volt/tailwind/compilation.ex
new file mode 100644
index 0000000..33401a0
--- /dev/null
+++ b/lib/volt/tailwind/compilation.ex
@@ -0,0 +1,21 @@
+defmodule Volt.Tailwind.Compilation do
+  @moduledoc "Retained stylesheet compilation inputs for a Tailwind context."
+
+  defstruct css: nil, base: nil, minify: false
+
+  def new(opts) do
+    %__MODULE__{
+      css: Keyword.get(opts, :css),
+      base: Path.expand(Keyword.get(opts, :css_base) || File.cwd!()),
+      minify: Keyword.get(opts, :minify, false)
+    }
+  end
+
+  def update(%__MODULE__{} = compilation, opts) do
+    new(
+      css: Keyword.get(opts, :css, compilation.css),
+      css_base: Keyword.get(opts, :css_base, compilation.base),
+      minify: Keyword.get(opts, :minify, compilation.minify)
+    )
+  end
+end
diff --git a/lib/volt/tailwind/compile_error.ex b/lib/volt/tailwind/compile_error.ex
new file mode 100644
index 0000000..883686a
--- /dev/null
+++ b/lib/volt/tailwind/compile_error.ex
@@ -0,0 +1,4 @@
+defmodule Volt.Tailwind.CompileError do
+  @moduledoc "Compiler failure retaining dependencies needed to observe recovery."
+  defexception [:message, dependencies: []]
+end
diff --git a/lib/volt/tailwind/context.ex b/lib/volt/tailwind/context.ex
new file mode 100644
index 0000000..7cbfa8f
--- /dev/null
+++ b/lib/volt/tailwind/context.ex
@@ -0,0 +1,5 @@
+defmodule Volt.Tailwind.Context do
+  @moduledoc "A compiler handle tied to one QuickBEAM runtime generation."
+  @enforce_keys [:runtime, :id]
+  defstruct [:runtime, :id]
+end
diff --git a/lib/volt/tailwind/loader.ex b/lib/volt/tailwind/loader.ex
index 7b211a1..042f77e 100644
--- a/lib/volt/tailwind/loader.ex
+++ b/lib/volt/tailwind/loader.ex
@@ -1,66 +1,93 @@
 defmodule Volt.Tailwind.Loader do
   @moduledoc "Handles Tailwind module loading, prebundling CJS graphs via OXC, and stylesheet resolution."
 
+  alias Volt.JS.Runtime.PackageSet
   alias Volt.JS.Transforms.Specifiers
   alias Volt.Tailwind.Resolver
 
-  @tailwind_install_spec "^4.3.0"
   @tailwind_runtime_deps %{
-    "tailwindcss" => @tailwind_install_spec,
-    "@tailwindcss/typography" => "*"
+    "tailwindcss" => "4.3.3",
+    "@tailwindcss/typography" => "0.5.20"
   }
+  @runtime_package_set PackageSet.bundled(:volt, :tailwind, @tailwind_runtime_deps)
 
   def runtime_packages, do: @tailwind_runtime_deps
+  def runtime_package_set, do: @runtime_package_set
 
   def handlers(runtime_node_modules) do
     %{
-      "tailwind.load_stylesheet" => fn [id, base] ->
-        load_stylesheet(id, base, runtime_node_modules)
+      "tailwind.scan" => fn [sources] ->
+        sources
+        |> Enum.map(fn %{"base" => base, "pattern" => pattern, "negated" => negated} ->
+          %Oxide.Source{base: Path.expand(base), pattern: pattern, negated: negated}
+        end)
+        |> then(&Oxide.new(sources: &1))
+        |> Oxide.scan()
+      end,
+      "tailwind.load_stylesheet" => fn [id, base, output_base] ->
+        capture_resolution(fn -> load_stylesheet(id, base, output_base, runtime_node_modules) end)
       end,
       "tailwind.load_module" => fn [id, base, kind] ->
-        load_module(id, base, kind, runtime_node_modules)
+        capture_resolution(fn -> load_module(id, base, kind, runtime_node_modules) end)
       end
     }
   end
 
-  defp load_stylesheet(id, base, runtime_node_modules) do
+  defp capture_resolution(load) do
+    load.()
+  rescue
+    error in Volt.Tailwind.ResolveError ->
+      %{error: Exception.message(error), candidates: error.candidates}
+  end
+
+  defp load_stylesheet(id, base, output_base, runtime_node_modules) do
     path = Resolver.resolve_stylesheet_path!(id, base, runtime_node_modules)
+    {:ok, content} = Volt.CSS.AssetURLRewriter.rebase(File.read!(path), path, output_base)
 
     %{
+      path: path,
       base: Path.dirname(path),
-      content: File.read!(path)
+      content: content
     }
   end
 
   defp load_module(id, base, kind, runtime_node_modules) do
     path = Resolver.resolve_module_path!(id, base, kind, runtime_node_modules)
 
-    {code, format} =
+    {code, format, dependencies} =
       if Path.extname(path) == ".json" do
-        {File.read!(path), "json"}
+        {File.read!(path), "json", [path]}
       else
-        {bundle_module_source!(path, runtime_node_modules), "cjs"}
+        {code, dependencies} = bundle_module_source!(path, runtime_node_modules)
+        {code, "cjs", dependencies}
       end
 
     %{
       path: path,
       base: Path.dirname(path),
       code: code,
+      dependencies: dependencies,
       format: format
     }
   end
 
   defp bundle_module_source!(entry_path, runtime_node_modules) do
     with {:ok, files} <- collect_bundle_files(entry_path, runtime_node_modules) do
+      dependencies = Enum.map(files, fn {path, _source} -> path end)
+
       case OXC.bundle(files, entry: entry_path, format: :cjs) do
         {:ok, code} when is_binary(code) ->
-          code
+          {code, dependencies}
 
         {:ok, %{code: code}} when is_binary(code) ->
-          code
+          {code, dependencies}
 
         {:error, errors} ->
-          raise "Could not bundle Tailwind module #{inspect(entry_path)}: #{inspect(errors)}"
+          raise OXC.Error,
+            message:
+              "Could not bundle Tailwind module #{inspect(entry_path)}:\n" <>
+                Enum.map_join(errors, "\n", &OXC.Diagnostic.format/1),
+            errors: errors
       end
     else
       {:error, reason} ->
diff --git a/lib/volt/tailwind/metadata.ex b/lib/volt/tailwind/metadata.ex
new file mode 100644
index 0000000..9f67932
--- /dev/null
+++ b/lib/volt/tailwind/metadata.ex
@@ -0,0 +1,28 @@
+defmodule Volt.Tailwind.Metadata do
+  @moduledoc "Compiler-discovered inputs decoded at the JavaScript boundary."
+
+  defstruct [:code, :root, dependencies: [], sources: []]
+
+  def decode(%{
+        "code" => code,
+        "root" => root,
+        "dependencies" => dependencies,
+        "sources" => sources
+      }) do
+    %__MODULE__{
+      code: code,
+      root: root(root),
+      dependencies: dependencies,
+      sources:
+        Enum.map(sources, fn %{"base" => base, "pattern" => pattern, "negated" => negated} ->
+          %Oxide.Source{base: base, pattern: pattern, negated: negated}
+        end)
+    }
+  end
+
+  defp root(nil), do: :automatic
+  defp root("none"), do: :none
+
+  defp root(%{"base" => base, "pattern" => pattern}),
+    do: %Oxide.Source{base: base, pattern: pattern, negated: false}
+end
diff --git a/lib/volt/tailwind/resolve_error.ex b/lib/volt/tailwind/resolve_error.ex
new file mode 100644
index 0000000..a4bbacb
--- /dev/null
+++ b/lib/volt/tailwind/resolve_error.ex
@@ -0,0 +1,4 @@
+defmodule Volt.Tailwind.ResolveError do
+  @moduledoc "A failed file resolution with the exact candidates attempted by the resolver."
+  defexception [:message, candidates: []]
+end
diff --git a/lib/volt/tailwind/resolver.ex b/lib/volt/tailwind/resolver.ex
index 57f5292..0b8e93b 100644
--- a/lib/volt/tailwind/resolver.ex
+++ b/lib/volt/tailwind/resolver.ex
@@ -42,19 +42,23 @@ defmodule Volt.Tailwind.Resolver do
     end
   end
 
-  def node_builtin_specifier?(specifier),
-    do: NPM.Resolution.PackageResolver.node_builtin?(specifier)
+  def node_builtin_specifier?(specifier), do: Volt.JS.Specifier.node_builtin?(specifier)
 
   def relative_specifier?(specifier), do: NPM.Resolution.PackageResolver.relative?(specifier)
-  def absolute_specifier?(specifier), do: String.starts_with?(specifier, "/")
+
+  def absolute_specifier?(specifier),
+    do: Path.type(specifier) in [:absolute, :volumerelative]
 
   defp resolve_bare_path!(id, base, extensions, index_files, kind, runtime_node_modules) do
     {package_name, subpath} = NPM.Resolution.PackageResolver.split_specifier(id)
 
-    resolved =
+    search_dirs =
       ([find_node_modules_for(base), runtime_node_modules] ++ phoenix_tailwind_search_dirs())
       |> Enum.reject(&is_nil/1)
       |> Enum.uniq()
+
+    resolved =
+      search_dirs
       |> Enum.find_value(fn node_modules ->
         package_dir = Path.join(node_modules, package_name)
 
@@ -75,10 +79,29 @@ defmodule Volt.Tailwind.Resolver do
 
     case resolved do
       {:ok, path} ->
-        path
+        Path.expand(path)
 
       nil ->
-        raise "Could not resolve #{kind} #{inspect(id)} from #{inspect(base)}. Add it to node_modules or the Tailwind runtime install."
+        candidates =
+          Enum.flat_map(search_dirs, fn directory ->
+            package = Path.join(directory, package_name)
+
+            target =
+              Path.join(
+                package,
+                if(subpath, do: String.trim_leading(subpath, "./"), else: "index")
+              )
+
+            [
+              Path.join(package, "package.json")
+              | Enum.map(extensions ++ index_files, &(target <> &1))
+            ]
+          end)
+
+        raise Volt.Tailwind.ResolveError,
+          message:
+            "Could not resolve #{kind} #{inspect(id)} from #{inspect(base)}. Add it to node_modules or the Tailwind runtime install.",
+          candidates: candidates
     end
   end
 
@@ -115,10 +138,13 @@ defmodule Volt.Tailwind.Resolver do
 
     case try_resolve(target, extensions, index_files) do
       {:ok, path} ->
-        path
+        Path.expand(path)
 
       {:error, reason} ->
-        raise "Could not resolve file #{inspect(id)} from #{inspect(base)}: #{inspect(reason)}"
+        raise Volt.Tailwind.ResolveError,
+          message:
+            "Could not resolve file #{inspect(id)} from #{inspect(base)}: #{inspect(reason)}",
+          candidates: Enum.map(extensions ++ index_files, &(target <> &1))
     end
   end
 
diff --git a/lib/volt/tailwind/runtime.ex b/lib/volt/tailwind/runtime.ex
new file mode 100644
index 0000000..13d8926
--- /dev/null
+++ b/lib/volt/tailwind/runtime.ex
@@ -0,0 +1,153 @@
+defmodule Volt.Tailwind.Runtime do
+  @moduledoc false
+
+  use GenServer
+
+  @name __MODULE__
+
+  def start_link(opts) do
+    GenServer.start_link(__MODULE__, :ok, name: Keyword.get(opts, :name, @name))
+  end
+
+  @spec call(String.t() | nil, [String.t()], String.t()) :: {:ok, String.t()} | {:error, term()}
+  def call(css, candidates, css_base, server \\ @name) do
+    GenServer.call(server, {:compile, css, candidates, css_base}, :infinity)
+  end
+
+  def prepare_context(css, base, server),
+    do: GenServer.call(server, {:prepare_context, css, base}, :infinity)
+
+  def build_context(context, candidates, server),
+    do: GenServer.call(server, {:build_context, context, candidates}, :infinity)
+
+  def release_context(context, server),
+    do: GenServer.call(server, {:release_context, context}, :infinity)
+
+  @doc "Compile and return source/dependency metadata for development invalidation."
+  def compile_metadata(css, candidates, css_base, server) do
+    GenServer.call(server, {:compile_metadata, css, candidates, css_base}, :infinity)
+  end
+
+  @doc "Compile once in an isolated runtime, releasing it when compilation finishes."
+  @spec compile_once(String.t() | nil, [String.t()], String.t()) ::
+          {:ok, String.t()} | {:error, term()}
+  def compile_once(css, candidates, css_base, scan \\ nil) do
+    runtime = start_runtime()
+
+    try do
+      runtime
+      |> Volt.JS.Runtime.call("compileTailwindCss", [css, candidates, css_base, scan])
+      |> normalize_result()
+    after
+      if Process.alive?(runtime.pid), do: Volt.JS.Runtime.stop(runtime)
+    end
+  end
+
+  @impl true
+  def init(:ok) do
+    Process.flag(:trap_exit, true)
+    {:ok, nil}
+  end
+
+  @impl true
+  def handle_call({:prepare_context, css, base}, _from, runtime) do
+    runtime = if runtime && Process.alive?(runtime.pid), do: runtime, else: start_runtime()
+
+    case invoke(runtime, "prepareTailwindContext", [css, base]) do
+      {:ok, %{"error" => message, "dependencies" => dependencies}} ->
+        {:reply,
+         {:error, %Volt.Tailwind.CompileError{message: message, dependencies: dependencies}},
+         runtime}
+
+      {:ok, %{"id" => id} = metadata} ->
+        {:reply,
+         {:ok, %Volt.Tailwind.Context{runtime: runtime.pid, id: id},
+          Volt.Tailwind.Metadata.decode(metadata)}, runtime}
+
+      error ->
+        {:reply, error, runtime}
+    end
+  end
+
+  def handle_call(
+        {:build_context, %Volt.Tailwind.Context{} = context, candidates},
+        _from,
+        runtime
+      ) do
+    if runtime && runtime.pid == context.runtime && Process.alive?(runtime.pid) do
+      {:reply, invoke(runtime, "buildTailwindContext", [context.id, candidates]), runtime}
+    else
+      {:reply, {:error, :stale_compiler_context}, runtime}
+    end
+  end
+
+  def handle_call({:release_context, context}, _from, runtime) do
+    if runtime && runtime.pid == context.runtime && Process.alive?(runtime.pid) do
+      invoke(runtime, "releaseTailwindContext", [context.id])
+    end
+
+    {:reply, :ok, runtime}
+  end
+
+  def handle_call({:compile_metadata, css, candidates, css_base}, _from, runtime) do
+    execute(runtime, [css, candidates, css_base, nil, true], fn
+      {:ok, result} -> {:ok, Volt.Tailwind.Metadata.decode(result)}
+      {:error, _} = error -> error
+    end)
+  end
+
+  def handle_call({:compile, css, candidates, css_base}, _from, runtime) do
+    execute(runtime, [css, candidates, css_base], &normalize_result/1)
+  end
+
+  defp execute(runtime, args, decode) do
+    runtime = if runtime && Process.alive?(runtime.pid), do: runtime, else: start_runtime()
+
+    try do
+      result = Volt.JS.Runtime.call(runtime, "compileTailwindCss", args)
+      {:reply, decode.(result), runtime}
+    catch
+      :exit, reason ->
+        if Process.alive?(runtime.pid), do: Volt.JS.Runtime.stop(runtime)
+        {:reply, {:error, {:compiler_exit, reason}}, nil}
+    end
+  end
+
+  @impl true
+  def handle_info({:EXIT, pid, _reason}, %{pid: pid}), do: {:noreply, nil}
+  def handle_info({:EXIT, _pid, _reason}, runtime), do: {:noreply, runtime}
+
+  @impl true
+  def terminate(_reason, nil), do: :ok
+
+  def terminate(_reason, runtime) do
+    if Process.alive?(runtime.pid), do: Volt.JS.Runtime.stop(runtime)
+    :ok
+  end
+
+  defp invoke(runtime, function, args) do
+    Volt.JS.Runtime.call(runtime, function, args)
+  catch
+    :exit, reason -> {:error, {:compiler_exit, reason}}
+  end
+
+  defp start_runtime do
+    Volt.JS.Runtime.PackageSet.runtime_opts(
+      Volt.Tailwind.Loader.runtime_package_set(),
+      apis: [:browser, :node],
+      handlers: fn runtime -> Volt.Tailwind.Loader.handlers(runtime.node_modules) end,
+      define: fn runtime ->
+        %{
+          "TAILWIND_ROOT" => Volt.JS.Runtime.package_path!(runtime, "tailwindcss"),
+          "TAILWIND_DEFAULT_BASE" => File.cwd!()
+        }
+      end,
+      entry: {:volt_asset, "compilers/tailwind.ts"}
+    )
+    |> Volt.JS.Runtime.ensure!()
+  end
+
+  defp normalize_result({:ok, result}) when is_binary(result), do: {:ok, result}
+  defp normalize_result({:ok, _result}), do: {:error, :unexpected_result}
+  defp normalize_result({:error, _reason} = error), do: error
+end
diff --git a/lib/volt/tailwind/state.ex b/lib/volt/tailwind/state.ex
new file mode 100644
index 0000000..fee6ac6
--- /dev/null
+++ b/lib/volt/tailwind/state.ex
@@ -0,0 +1,16 @@
+defmodule Volt.Tailwind.State do
+  @moduledoc false
+
+  @enforce_keys [:key, :sources]
+  defstruct [
+    :key,
+    :scanner,
+    :last_css,
+    :sources,
+    :compilation,
+    :runtime,
+    :context,
+    configured_sources: [],
+    dependencies: []
+  ]
+end
diff --git a/lib/volt/tailwind/supervisor.ex b/lib/volt/tailwind/supervisor.ex
new file mode 100644
index 0000000..f205b81
--- /dev/null
+++ b/lib/volt/tailwind/supervisor.ex
@@ -0,0 +1,55 @@
+defmodule Volt.Tailwind.Supervisor do
+  @moduledoc false
+
+  @registry Volt.Tailwind.Registry
+  @supervisor Volt.Tailwind.WorkerSupervisor
+
+  @doc "Release a compiler context without affecting other registered roots."
+  def release(key) do
+    case Registry.lookup(@registry, key) do
+      [] -> :ok
+      [{pid, _}] -> DynamicSupervisor.terminate_child(@supervisor, pid)
+    end
+  end
+
+  @doc "Resolve a lazy runtime shared only by contexts in one explicit session."
+  def runtime({:session, session, _key}) do
+    key = {:runtime, session}
+    name = {:via, Registry, {@registry, key}}
+
+    case Registry.lookup(@registry, key) do
+      [{pid, _}] ->
+        pid
+
+      [] ->
+        case DynamicSupervisor.start_child(@supervisor, {Volt.Tailwind.Runtime, [name: name]}) do
+          {:ok, pid} -> pid
+          {:error, {:already_started, pid}} -> pid
+        end
+    end
+  end
+
+  def runtime(_key), do: Volt.Tailwind.Runtime
+
+  @doc "Release the compiler runtime owned by an explicit session."
+  def release_runtime(session), do: release({:runtime, session})
+
+  @spec worker(term(), keyword()) :: GenServer.server()
+  def worker(key, opts) do
+    name = {:via, Registry, {@registry, key}}
+
+    case Registry.lookup(@registry, key) do
+      [{pid, _value}] ->
+        pid
+
+      [] ->
+        spec = {Volt.Tailwind.Worker, Keyword.merge(opts, key: key, name: name)}
+
+        case DynamicSupervisor.start_child(@supervisor, spec) do
+          {:ok, pid} -> pid
+          {:error, {:already_started, pid}} -> pid
+          {:error, reason} -> raise "could not start Tailwind worker: #{inspect(reason)}"
+        end
+    end
+  end
+end
diff --git a/lib/volt/tailwind/worker.ex b/lib/volt/tailwind/worker.ex
new file mode 100644
index 0000000..4201b96
--- /dev/null
+++ b/lib/volt/tailwind/worker.ex
@@ -0,0 +1,237 @@
+defmodule Volt.Tailwind.Worker do
+  @moduledoc false
+
+  use GenServer
+
+  alias Volt.Tailwind.{State, Runtime}
+
+  def start_link(opts) do
+    GenServer.start_link(__MODULE__, opts, name: Keyword.fetch!(opts, :name))
+  end
+
+  @impl true
+  def init(opts) do
+    Process.flag(:trap_exit, true)
+
+    {:ok,
+     %State{
+       key: Keyword.fetch!(opts, :key),
+       runtime: Keyword.get(opts, :runtime),
+       scanner: nil,
+       last_css: nil,
+       configured_sources: Keyword.get(opts, :sources, []),
+       sources: Keyword.get(opts, :sources, [])
+     }}
+  end
+
+  @doc "Return the last successfully compiled stylesheet without compiling."
+  def stylesheet(server), do: GenServer.call(server, :stylesheet)
+
+  def inputs(server), do: GenServer.call(server, :inputs)
+
+  @impl true
+  def handle_call(:inputs, _from, state),
+    do: {:reply, %{sources: state.sources, dependencies: state.dependencies}, state}
+
+  def handle_call(:stylesheet, _from, state) do
+    result = if is_binary(state.last_css), do: {:ok, state.last_css}, else: {:error, :not_built}
+    {:reply, result, state}
+  end
+
+  def handle_call({:build, opts}, _from, state) do
+    sources = Keyword.get(opts, :sources, state.configured_sources)
+    compilation = Volt.Tailwind.Compilation.new(opts)
+    runtime = state.runtime || Volt.Tailwind.Supervisor.runtime(state.key)
+    state = %{state | runtime: runtime}
+
+    with {:ok, context, metadata} <-
+           Runtime.prepare_context(compilation.css, compilation.base, runtime) do
+      configured = sources
+      sources = effective_sources(metadata, configured, compilation.base)
+      scanner = build_scanner(sources)
+
+      case finish_build(
+             state,
+             compilation,
+             scanner,
+             sources,
+             metadata.dependencies,
+             context,
+             runtime
+           ) do
+        {:reply, {:ok, css}, updated} ->
+          {:reply, {:ok, css}, %{updated | configured_sources: configured}}
+
+        error ->
+          error
+      end
+    else
+      {:error, %Volt.Tailwind.CompileError{dependencies: dependencies}} = error ->
+        {:reply, error, %{state | dependencies: Enum.uniq(state.dependencies ++ dependencies)}}
+
+      {:error, _} = error ->
+        {:reply, error, state}
+    end
+  end
+
+  def handle_call({:rebuild, changed_files, opts}, _from, state) do
+    case state.scanner do
+      nil when not is_nil(state.compilation) ->
+        compilation = Volt.Tailwind.Compilation.update(state.compilation, opts)
+        runtime = state.runtime || Volt.Tailwind.Supervisor.runtime(state.key)
+        restore_context(state, compilation, runtime)
+
+      nil ->
+        {:reply, {:error, :no_scanner}, state}
+
+      scanner ->
+        rebuild_css(state, scanner, changed_files, opts)
+    end
+  end
+
+  defp finish_build(state, compilation, scanner, sources, dependencies, context, runtime) do
+    case Runtime.build_context(context, scan(scanner), runtime) do
+      {:ok, css} ->
+        css = maybe_minify(css, compilation.minify)
+
+        if state.context, do: Runtime.release_context(state.context, runtime)
+
+        {:reply, {:ok, css},
+         %{
+           state
+           | context: context,
+             scanner: scanner,
+             last_css: css,
+             sources: sources,
+             compilation: compilation,
+             dependencies: dependencies
+         }}
+
+      {:error, _reason} = error ->
+        Runtime.release_context(context, runtime)
+        {:reply, error, state}
+    end
+  end
+
+  defp rebuild_css(state, scanner, changed_files, opts) do
+    changed = Enum.map(changed_files, &changed_file/1)
+
+    new_candidates = Oxide.scan_files(scanner, changed)
+    compilation = Volt.Tailwind.Compilation.update(state.compilation, opts)
+    stale? = is_nil(state.context) or not Process.alive?(state.context.runtime)
+
+    if new_candidates == [] and not stale? and compilation == state.compilation do
+      {:reply, :unchanged, state}
+    else
+      compile_rebuilt_css(state, scanner, opts)
+    end
+  end
+
+  defp compile_rebuilt_css(state, scanner, opts) do
+    compilation = Volt.Tailwind.Compilation.update(state.compilation, opts)
+
+    runtime = state.runtime || Volt.Tailwind.Supervisor.runtime(state.key)
+    candidates = Oxide.scan(scanner)
+
+    result =
+      if state.context && compilation == state.compilation do
+        Runtime.build_context(state.context, candidates, runtime)
+      else
+        {:error, :stale_compiler_context}
+      end
+
+    case result do
+      {:ok, css} ->
+        css = maybe_minify(css, compilation.minify)
+        reply = if css == state.last_css, do: :unchanged, else: {:ok, css}
+        {:reply, reply, %{state | last_css: css, compilation: compilation}}
+
+      {:error, :stale_compiler_context} ->
+        restore_context(state, compilation, runtime)
+
+      {:error, _reason} = error ->
+        {:reply, error, state}
+    end
+  end
+
+  defp restore_context(state, compilation, runtime) do
+    with {:ok, context, metadata} <-
+           Runtime.prepare_context(compilation.css, compilation.base, runtime) do
+      sources = effective_sources(metadata, state.configured_sources, compilation.base)
+      scanner = build_scanner(sources)
+
+      case Runtime.build_context(context, scan(scanner), runtime) do
+        {:ok, css} ->
+          css = maybe_minify(css, compilation.minify)
+          if state.context, do: Runtime.release_context(state.context, runtime)
+          reply = if css == state.last_css, do: :unchanged, else: {:ok, css}
+
+          {:reply, reply,
+           %{
+             state
+             | context: context,
+               scanner: scanner,
+               sources: sources,
+               compilation: compilation,
+               last_css: css,
+               dependencies: metadata.dependencies
+           }}
+
+        {:error, _} = error ->
+          Runtime.release_context(context, runtime)
+          {:reply, error, state}
+      end
+    else
+      {:error, _} = error -> {:reply, error, state}
+    end
+  end
+
+  defp effective_sources(metadata, configured, base) do
+    automatic =
+      case metadata.root do
+        :none -> []
+        :automatic -> if configured == [], do: [%{base: base, pattern: "**/*"}], else: []
+        source -> [source]
+      end
+
+    Enum.uniq(automatic ++ configured ++ metadata.sources)
+  end
+
+  defp build_scanner([]), do: nil
+  defp build_scanner(sources), do: Oxide.new(sources: Enum.map(sources, &source/1))
+  defp scan(nil), do: []
+  defp scan(scanner), do: Oxide.scan(scanner)
+
+  defp source(%{base: base, pattern: pattern} = source) do
+    %Oxide.Source{
+      base: Path.expand(base),
+      pattern: pattern,
+      negated: Map.get(source, :negated, false)
+    }
+  end
+
+  defp changed_file(path) when is_binary(path) do
+    %Oxide.Changed{file: path, extension: path |> Path.extname() |> String.trim_leading(".")}
+  end
+
+  defp changed_file(map), do: struct!(Oxide.Changed, map)
+
+  @impl true
+  def terminate(_reason, %{context: nil}), do: :ok
+
+  def terminate(_reason, state) do
+    runtime = state.runtime || Volt.Tailwind.Runtime
+    if GenServer.whereis(runtime), do: Runtime.release_context(state.context, runtime)
+    :ok
+  catch
+    :exit, _reason -> :ok
+  end
+
+  defp maybe_minify(css, false), do: css
+
+  defp maybe_minify(css, true) do
+    case Vize.CSS.compile(css, minify: true) do
+      {:ok, %{code: minified}} -> minified
+    end
+  end
+end
diff --git a/lib/volt/test/browser.ex b/lib/volt/test/browser.ex
new file mode 100644
index 0000000..eed2a6d
--- /dev/null
+++ b/lib/volt/test/browser.ex
@@ -0,0 +1,231 @@
+defmodule Volt.Test.Browser do
+  @moduledoc """
+  The browser a test run shares.
+
+  Browsers are launched once per type, the first time a test asks for one,
+  and every test gets a browser context of its own, which isolates its
+  storage, cookies and pages the way a browser of its own would. See
+  `with_page/3`.
+
+  The process also keeps what the contexts load: the test runtime,
+  `priv/ts/test/browser.ts`, bundled once when the run starts and installed
+  in every context before its page loads, and the bundled test modules,
+  written to `_build/volt/browser-tests`, emptied when the run starts, and
+  reused while the source files they were bundled from keep their
+  modification times. See `module/2`.
+
+  `Volt.Test.Browser.Supervisor` starts this process next to the Playwright
+  driver.
+  """
+
+  use GenServer
+
+  alias Volt.Test.Browser.Supervisor, as: Tree
+
+  @table __MODULE__
+
+  @type launched :: %{guid: String.t()}
+
+  @doc false
+  def start_link(opts) do
+    GenServer.start_link(__MODULE__, opts, name: __MODULE__)
+  end
+
+  @doc """
+  Open a context in the browser of `type`, with the test runtime installed
+  and a page on the blank document, and call `fun` with the page's main frame.
+
+  The context closes when `fun` returns or raises. A browser that is no longer
+  reachable, because it crashed since it was launched, is launched again once.
+  """
+  @spec with_page(atom(), timeout(), (map() -> result)) :: result | {:error, term()}
+        when result: term()
+  def with_page(type, timeout, fun) do
+    with {:ok, browser} <- launch(type, timeout),
+         {:ok, context} <- new_context(browser, type, timeout) do
+      try do
+        with {:ok, _} <- browser_context_add_init_script(context.guid, runtime(), timeout),
+             {:ok, %{main_frame: frame}} <- browser_context_new_page(context.guid, timeout),
+             {:ok, _} <- frame_goto(frame.guid, page_url(), timeout) do
+          fun.(frame)
+        end
+      after
+        browser_context_close(context.guid, timeout)
+      end
+    end
+  end
+
+  defp new_context(browser, type, timeout) do
+    case browser_new_context(browser.guid, timeout) do
+      {:ok, context} ->
+        {:ok, context}
+
+      {:error, _reason} ->
+        with :ok <- forget(type, browser.guid),
+             {:ok, browser} <- launch(type, timeout) do
+          browser_new_context(browser.guid, timeout)
+        end
+    end
+  end
+
+  @doc "The browser of `type`, launched on first request."
+  @spec launch(atom(), timeout()) :: {:ok, launched()} | {:error, term()}
+  def launch(type, timeout) do
+    GenServer.call(__MODULE__, {:launch, type, timeout}, :infinity)
+  end
+
+  @doc "Drop a browser that is no longer reachable, so the next request launches a new one."
+  @spec forget(atom(), String.t()) :: :ok
+  def forget(type, guid) do
+    GenServer.call(__MODULE__, {:forget, type, guid})
+  end
+
+  @doc """
+  The `file:` URL of the bundled module for the test file at `path`, bundled
+  with `bundle_opts`.
+
+  Bundling happens in the caller, so tests of different files bundle
+  concurrently. Modules are named by their content, so two callers bundling
+  the same file at once write the same module.
+  """
+  @spec module(Path.t(), keyword()) :: {:ok, String.t()} | {:error, term()}
+  def module(path, bundle_opts) do
+    key = {Path.expand(path), bundle_opts}
+
+    case :ets.lookup(@table, key) do
+      [{^key, %{sources: sources, url: url}}] ->
+        if sources == modification_times(sources), do: {:ok, url}, else: bundle(key, bundle_opts)
+
+      [] ->
+        bundle(key, bundle_opts)
+    end
+  end
+
+  defp bundle(key, bundle_opts) do
+    with {:ok, bundled} <- Volt.Builder.bundle(bundle_opts),
+         {:ok, url} <- write_module(bundled.code) do
+      sources = modification_times(Enum.map(bundled.files, &{&1, nil}))
+      :ets.insert(@table, {key, %{sources: sources, url: url}})
+      {:ok, url}
+    end
+  end
+
+  defp modification_times(sources) do
+    Enum.map(sources, fn {path, _mtime} ->
+      case File.stat(path, time: :posix) do
+        {:ok, %File.Stat{mtime: mtime}} -> {path, mtime}
+        {:error, _reason} -> {path, nil}
+      end
+    end)
+  end
+
+  defp write_module(code) do
+    name = Base.url_encode64(:crypto.hash(:sha256, code), padding: false) <> ".mjs"
+    path = Path.join(dir(), name)
+
+    if File.regular?(path) do
+      {:ok, file_url(path)}
+    else
+      with :ok <- File.write(path, code), do: {:ok, file_url(path)}
+    end
+  end
+
+  defp page_url, do: file_url(Path.join(dir(), "index.html"))
+  defp runtime, do: :ets.lookup_element(@table, :runtime, 2)
+  defp dir, do: :ets.lookup_element(@table, :dir, 2)
+
+  defp file_url(path) do
+    %URI{scheme: "file", path: path} |> URI.to_string()
+  end
+
+  @impl true
+  def init(_opts) do
+    # The VM halts at the end of `mix test` without stopping applications, so
+    # the directory is emptied at the start of a run rather than at its end.
+    dir = Volt.Paths.expand(Path.join(build_path(), "volt/browser-tests"))
+
+    with {:ok, runtime} <- Volt.Priv.bundle({:volt, "ts"}, "test/browser.ts"),
+         {:ok, _removed} <- File.rm_rf(dir),
+         :ok <- File.mkdir_p(dir),
+         :ok <-
+           File.write(Path.join(dir, "index.html"), "<!doctype html><meta charset=\"utf-8\">") do
+      # The table appears once the process can serve from it. Callers reach it
+      # after `launch/2`, which waits for this initialization.
+      :ets.new(@table, [:named_table, :set, :public, read_concurrency: true])
+      :ets.insert(@table, [{:dir, dir}, {:runtime, runtime}])
+      {:ok, %{browsers: %{}}}
+    else
+      {:error, reason} -> {:stop, {:browser_tests, reason}}
+    end
+  end
+
+  defp build_path, do: System.get_env("MIX_BUILD_PATH") || "_build"
+
+  @impl true
+  def handle_call({:launch, type, timeout}, _from, state) do
+    case Map.fetch(state.browsers, type) do
+      {:ok, browser} ->
+        {:reply, {:ok, browser}, state}
+
+      :error ->
+        case launch_browser(type, timeout) do
+          {:ok, browser} ->
+            {:reply, {:ok, browser}, put_in(state.browsers[type], browser)}
+
+          {:error, reason} ->
+            {:reply, {:error, reason}, state}
+        end
+    end
+  end
+
+  def handle_call({:forget, type, guid}, _from, state) do
+    case state.browsers do
+      %{^type => %{guid: ^guid}} ->
+        {:reply, :ok, %{state | browsers: Map.delete(state.browsers, type)}}
+
+      _other ->
+        {:reply, :ok, state}
+    end
+  end
+
+  # The playwright_ex dependency is only present in test environments, so its
+  # functions are called without compile-time references.
+  defp launch_browser(type, timeout) do
+    apply(PlaywrightEx, :launch_browser, [type, [connection: Tree.connection(), timeout: timeout]])
+  end
+
+  defp browser_new_context(browser_guid, timeout) do
+    apply(PlaywrightEx.Browser, :new_context, [
+      browser_guid,
+      [connection: Tree.connection(), timeout: timeout]
+    ])
+  end
+
+  defp browser_context_add_init_script(context_guid, source, timeout) do
+    apply(PlaywrightEx.BrowserContext, :add_init_script, [
+      context_guid,
+      [source: source, connection: Tree.connection(), timeout: timeout]
+    ])
+  end
+
+  defp browser_context_new_page(context_guid, timeout) do
+    apply(PlaywrightEx.BrowserContext, :new_page, [
+      context_guid,
+      [connection: Tree.connection(), timeout: timeout]
+    ])
+  end
+
+  defp browser_context_close(context_guid, timeout) do
+    apply(PlaywrightEx.BrowserContext, :close, [
+      context_guid,
+      [connection: Tree.connection(), timeout: timeout]
+    ])
+  end
+
+  defp frame_goto(frame_guid, url, timeout) do
+    apply(PlaywrightEx.Frame, :goto, [
+      frame_guid,
+      [url: url, connection: Tree.connection(), timeout: timeout]
+    ])
+  end
+end
diff --git a/lib/volt/test/browser/supervisor.ex b/lib/volt/test/browser/supervisor.ex
new file mode 100644
index 0000000..0a8a56f
--- /dev/null
+++ b/lib/volt/test/browser/supervisor.ex
@@ -0,0 +1,82 @@
+defmodule Volt.Test.Browser.Supervisor do
+  @moduledoc """
+  Supervises what a test run keeps for its browser tests: the Playwright
+  driver and `Volt.Test.Browser`, which launches browsers in it.
+
+  Starting the driver and launching a browser each cost more than running a
+  test, so both outlive the tests. The tree is started under `Volt.Supervisor`
+  on first use, with the `:playwright` options of the configuration that
+  started it, and goes away only with the VM.
+  """
+
+  use Supervisor
+
+  alias Volt.Test.Config
+
+  @playwright Volt.Test.Browser.Playwright
+
+  @doc """
+  Start the tree, or find it already running.
+
+  The tree lives under `Volt.Supervisor`, so Volt's application is started
+  first: a project that depends on Volt with `runtime: false` has not started
+  it.
+  """
+  @spec start(Config.t()) :: {:ok, pid()} | {:error, term()}
+  def start(%Config{} = config) do
+    with {:ok, _started} <- Application.ensure_all_started(:volt) do
+      case Supervisor.start_child(Volt.Supervisor, {__MODULE__, config}) do
+        {:ok, pid} -> {:ok, pid}
+        {:error, {:already_started, pid}} -> {:ok, pid}
+        {:error, reason} -> {:error, reason}
+      end
+    end
+  end
+
+  @doc false
+  def child_spec(config) do
+    %{
+      id: __MODULE__,
+      start: {__MODULE__, :start_link, [config]},
+      restart: :temporary,
+      type: :supervisor
+    }
+  end
+
+  @doc false
+  def start_link(%Config{} = config) do
+    Supervisor.start_link(__MODULE__, config, name: __MODULE__)
+  end
+
+  @impl true
+  def init(%Config{} = config) do
+    # The driver is a port and the browsers are its children, so a driver
+    # that went away takes the launched browsers with it.
+    children = [
+      %{
+        id: @playwright,
+        start: {PlaywrightEx.Supervisor, :start_link, [playwright_opts(config)]},
+        type: :supervisor
+      },
+      Volt.Test.Browser
+    ]
+
+    Supervisor.init(children, strategy: :rest_for_one)
+  end
+
+  @doc "The Playwright connection the run's browsers belong to."
+  @spec connection() :: GenServer.name()
+  def connection, do: Module.concat(@playwright, "Connection")
+
+  defp playwright_opts(%Config{} = config) do
+    config.playwright
+    |> Keyword.put_new(:timeout, config.timeout)
+    |> Keyword.put_new(:executable, playwright_executable())
+    |> Keyword.put(:name, @playwright)
+  end
+
+  defp playwright_executable do
+    local = Path.expand("node_modules/playwright/cli.js", Volt.Paths.root())
+    if File.exists?(local), do: local, else: "playwright"
+  end
+end
diff --git a/lib/volt/test/browser_runner.ex b/lib/volt/test/browser_runner.ex
index dd73283..ebaf8fb 100644
--- a/lib/volt/test/browser_runner.ex
+++ b/lib/volt/test/browser_runner.ex
@@ -5,8 +5,12 @@ defmodule Volt.Test.BrowserRunner do
   This runner is intentionally small and mirrors `Volt.Test.Runner`'s result
   contract so ExUnit integration can switch between QuickBEAM and browser
   execution without changing assertions or reporting.
+
+  The browser belongs to the run (see `Volt.Test.Browser`); each call opens a
+  context in it, loads the file's bundled module and closes the context again.
   """
 
+  alias Volt.Test.Browser
   alias Volt.Test.Config
 
   @type result :: map()
@@ -37,117 +41,41 @@ defmodule Volt.Test.BrowserRunner do
     config = Keyword.fetch!(opts, :config)
     timeout = Keyword.get(opts, :timeout, config.timeout)
 
-    with {:ok, bundled} <- Volt.Builder.bundle(Volt.Test.Shared.bundle_opts(path, config, opts)),
-         {:ok, test_url, cleanup} <- write_browser_test_module(bundled.code),
-         {:ok, runtime_code} <- browser_runtime_code(),
-         :ok <- ensure_playwright_started(config, timeout),
-         {:ok, browser} <- launch_browser(browser(config), timeout: timeout),
-         {:ok, context} <- browser_new_context(browser.guid, timeout: timeout),
-         {:ok, %{main_frame: frame}} <- browser_context_new_page(context.guid, timeout: timeout),
-         {:ok, _} <- frame_goto(frame.guid, url: test_url.page, timeout: timeout) do
-      try do
-        evaluate(frame, runtime_code, test_url.module, path, mode, test_id, timeout)
-      after
-        cleanup.()
-        browser_context_close(context.guid, timeout: timeout)
-        browser_close(browser.guid, timeout: timeout)
-      end
-    end
-  end
-
-  defp browser_runtime_code do
-    Volt.JS.Runtime.Bundler.bundle_file(Volt.Priv.path({:volt, "ts"}, "test/browser.ts"))
-  end
-
-  defp ensure_playwright_started(%Config{} = config, timeout) do
-    opts =
-      config.playwright
-      |> Keyword.put_new(:timeout, timeout)
-      |> Keyword.put_new(:executable, playwright_executable())
-
-    case playwright_supervisor_start_link(opts) do
-      {:ok, _pid} -> :ok
-      {:error, {:already_started, _pid}} -> :ok
-      {:error, reason} -> {:error, reason}
+    with {:ok, _pid} <- Browser.Supervisor.start(config) do
+      Browser.with_page(browser(config), timeout, fn frame ->
+        with {:ok, module_url} <-
+               Browser.module(path, Volt.Test.Shared.bundle_opts(path, config, opts)) do
+          evaluate(frame, module_url, path, mode, test_id, timeout)
+        end
+      end)
     end
   end
 
-  defp playwright_executable do
-    local = Path.expand("node_modules/.bin/playwright")
-    if File.exists?(local), do: local, else: "playwright"
-  end
-
   defp browser(%Config{browsers: [browser | _]}), do: browser
   defp browser(%Config{}), do: :chromium
 
-  defp write_browser_test_module(code) do
-    dir = Path.join(System.tmp_dir!(), "volt-browser-test-#{System.unique_integer([:positive])}")
-    page_path = Path.join(dir, "index.html")
-    module_path = Path.join(dir, "test.mjs")
-
-    with :ok <- File.mkdir_p(dir),
-         :ok <- File.write(page_path, "<!doctype html><meta charset=\"utf-8\">"),
-         :ok <- File.write(module_path, code) do
-      {:ok, %{page: file_url(page_path), module: file_url(module_path)},
-       fn -> File.rm_rf(dir) end}
-    end
-  end
-
-  defp file_url(path) do
-    %URI{scheme: "file", path: Path.expand(path)} |> URI.to_string()
-  end
-
-  defp evaluate(frame, runtime_code, test_url, file, mode, test_id, timeout) do
-    with {:ok, _} <-
-           frame_evaluate(frame.guid,
-             expression: runtime_code,
-             is_function: false,
-             arg: nil,
-             timeout: timeout
-           ) do
-      frame_evaluate(frame.guid,
-        expression: "payload => globalThis.__voltExecuteBrowserTest(payload)",
-        is_function: true,
-        arg: %{
-          "testUrl" => test_url,
-          "file" => file,
-          "mode" => Atom.to_string(mode),
-          "testId" => test_id
-        },
-        timeout: timeout
-      )
-    end
-  end
-
-  defp playwright_supervisor_start_link(opts) do
-    apply(PlaywrightEx.Supervisor, :start_link, [opts])
-  end
-
-  defp launch_browser(browser, opts) do
-    apply(PlaywrightEx, :launch_browser, [browser, opts])
-  end
-
-  defp browser_new_context(browser_guid, opts) do
-    apply(PlaywrightEx.Browser, :new_context, [browser_guid, opts])
-  end
-
-  defp browser_close(browser_guid, opts) do
-    apply(PlaywrightEx.Browser, :close, [browser_guid, opts])
-  end
-
-  defp browser_context_new_page(context_guid, opts) do
-    apply(PlaywrightEx.BrowserContext, :new_page, [context_guid, opts])
-  end
-
-  defp browser_context_close(context_guid, opts) do
-    apply(PlaywrightEx.BrowserContext, :close, [context_guid, opts])
-  end
-
-  defp frame_goto(frame_guid, opts) do
-    apply(PlaywrightEx.Frame, :goto, [frame_guid, opts])
-  end
-
+  # The page the run opens carries the test runtime, so the frame already has
+  # `__voltExecuteBrowserTest`.
+  defp evaluate(frame, test_url, file, mode, test_id, timeout) do
+    frame_evaluate(frame.guid,
+      expression: "payload => globalThis.__voltExecuteBrowserTest(payload)",
+      is_function: true,
+      arg: %{
+        "testUrl" => test_url,
+        "file" => file,
+        "mode" => Atom.to_string(mode),
+        "testId" => test_id
+      },
+      timeout: timeout
+    )
+  end
+
+  # The playwright_ex dependency is only present in test environments, so its
+  # functions are called without compile-time references.
   defp frame_evaluate(frame_guid, opts) do
-    apply(PlaywrightEx.Frame, :evaluate, [frame_guid, opts])
+    apply(PlaywrightEx.Frame, :evaluate, [
+      frame_guid,
+      [connection: Browser.Supervisor.connection()] ++ opts
+    ])
   end
 end
diff --git a/lib/volt/test/case.ex b/lib/volt/test/case.ex
index e29f440..9be3623 100644
--- a/lib/volt/test/case.ex
+++ b/lib/volt/test/case.ex
@@ -10,11 +10,17 @@ defmodule Volt.Test.Case do
   use ExUnit.CaseTemplate
 
   using opts do
+    browser? = Keyword.get(opts, :browser, false)
+
     quote do
       import ExUnit.Assertions, except: [assert: 1, assert: 2]
       import Volt.Test.Assertions
       import Volt.Test.Sigils
 
+      if unquote(browser?) do
+        @moduletag browser_js: true
+      end
+
       @volt_test_config unquote(opts)
     end
   end
diff --git a/lib/volt/test/config.ex b/lib/volt/test/config.ex
index 6c8fe23..85bedb6 100644
--- a/lib/volt/test/config.ex
+++ b/lib/volt/test/config.ex
@@ -22,6 +22,7 @@ defmodule Volt.Test.Config do
             exclude: ["vendor/**", "node_modules/**" | Volt.Paths.ignored_globs()],
             setup_files: [],
             browser: false,
+            granularity: :test,
             browsers: [:chromium],
             timeout: 30_000,
             bundle: [],
@@ -34,6 +35,7 @@ defmodule Volt.Test.Config do
           exclude: [String.t()],
           setup_files: [String.t()],
           browser: boolean(),
+          granularity: :test | :file,
           browsers: [atom()],
           timeout: timeout(),
           bundle: keyword(),
@@ -47,6 +49,7 @@ defmodule Volt.Test.Config do
     :exclude,
     :setup_files,
     :browser,
+    :granularity,
     :browsers,
     :timeout,
     :bundle,
diff --git a/lib/volt/test/discovery.ex b/lib/volt/test/discovery.ex
index 2f260c0..7f54313 100644
--- a/lib/volt/test/discovery.ex
+++ b/lib/volt/test/discovery.ex
@@ -2,7 +2,7 @@ defmodule Volt.Test.Discovery do
   @moduledoc """
   Discovers JavaScript and TypeScript test files for the Volt test runner.
 
-  Discovery is intentionally aligned with `Volt.JS.Helpers`: configured include
+  Discovery is intentionally aligned with `Volt.JS.Discovery`: configured include
   globs are expanded relative to `Volt.Test.Config.root`, exclude globs are
   expanded from the same root, non-files are ignored, and results are sorted for
   deterministic ExUnit generation.
@@ -24,7 +24,7 @@ defmodule Volt.Test.Discovery do
   end
 
   defp discover(%Config{} = config) do
-    root = config.root
+    root = Path.expand(config.root)
 
     matched = expand_patterns(root, config.include)
     ignored = root |> expand_patterns(config.exclude) |> MapSet.new()
diff --git a/lib/volt/test/ex_unit.ex b/lib/volt/test/ex_unit.ex
index 4c595ad..6558b29 100644
--- a/lib/volt/test/ex_unit.ex
+++ b/lib/volt/test/ex_unit.ex
@@ -19,7 +19,14 @@ defmodule Volt.Test.ExUnit do
   in normal ExUnit tags, formatters, failures, and CI behavior.
 
   Pass `browser: true` to execute tests in a real Playwright browser instead
-  of QuickBEAM while keeping the same ExUnit registration model.
+  of QuickBEAM while keeping the same ExUnit registration model. The run
+  shares one browser (see `Volt.Test.Browser`), every test gets a browser
+  context of its own, and the generated modules are `async: true`.
+
+  By default, each JavaScript test becomes an ExUnit test. Pass
+  `granularity: :file` to register one ExUnit test per file and execute the
+  complete file in one runtime invocation. File granularity is useful for
+  large suites where repeatedly bundling and starting a runtime is too costly.
   """
 
   alias Volt.Test.Config
@@ -39,10 +46,16 @@ defmodule Volt.Test.ExUnit do
     module = module_name(file)
 
     unless Code.ensure_loaded?(module) do
-      tests = collect_tests!(file, profile, config)
+      quoted =
+        case config.granularity do
+          :test ->
+            bridge_module(module, file, profile, config, collect_tests!(file, profile, config))
 
-      [{_compiled_module, _bytecode}] =
-        Code.compile_quoted(bridge_module(module, file, profile, config, tests), file)
+          :file ->
+            file_bridge_module(module, file, profile, config)
+        end
+
+      [{_compiled_module, _bytecode}] = Code.compile_quoted(quoted, file)
     end
 
     module
@@ -66,13 +79,41 @@ defmodule Volt.Test.ExUnit do
 
     quote do
       defmodule unquote(module) do
-        use ExUnit.Case, async: false
+        use ExUnit.Case, async: unquote(async?(config))
 
         unquote_splicing(test_defs)
       end
     end
   end
 
+  defp file_bridge_module(module, file, profile, config) do
+    empty_message = "Volt JS test file #{file} did not define any tests"
+
+    quote do
+      defmodule unquote(module) do
+        use ExUnit.Case, async: unquote(async?(config))
+
+        @moduletag js: true
+        @moduletag volt_file: unquote(file)
+
+        if unquote(config.browser) do
+          @moduletag browser_js: true
+        end
+
+        test unquote(Path.relative_to(file, config.root)) do
+          assert {:ok, result} =
+                   unquote(runner(config)).run_file(unquote(file),
+                     profile: unquote(profile),
+                     config: unquote(Macro.escape(config))
+                   )
+
+          assert result.total > 0, unquote(empty_message)
+          Volt.Test.Assertions.assert_passed!(result)
+        end
+      end
+    end
+  end
+
   defp test_definition(file, profile, config, %Volt.Test.Result.Metadata{id: test_id} = test) do
     name = test.full_name || test.name || inspect(test_id)
     function = Macro.unique_var(:name, __MODULE__)
@@ -110,6 +151,11 @@ defmodule Volt.Test.ExUnit do
   defp runner(%Config{browser: true}), do: Volt.Test.BrowserRunner
   defp runner(%Config{}), do: Volt.Test.Runner
 
+  # Browser tests each run in a context of their own in the run's browser, so
+  # their modules run concurrently like any other async ExUnit modules.
+  defp async?(%Config{browser: true}), do: true
+  defp async?(%Config{}), do: false
+
   defp test_tags(file, test) do
     [
       js: true,
diff --git a/lib/volt/test/lines.ex b/lib/volt/test/lines.ex
index 97ededa..390242f 100644
--- a/lib/volt/test/lines.ex
+++ b/lib/volt/test/lines.ex
@@ -7,55 +7,120 @@ defmodule Volt.Test.Lines do
   at useful file lines without hand-parsing JavaScript.
   """
 
+  @doc """
+  Return the source line of every test in `source`, in the order the runtime
+  registers them.
+
+  `test.each` and `describe.each` register one test per case, so their lines
+  repeat once per case. Returns `{:error, :dynamic_cases}` when the cases are
+  not an array literal and the number of tests cannot be read from the source.
+  """
   @spec test_lines(String.t(), String.t()) :: {:ok, [pos_integer()]} | {:error, term()}
   def test_lines(source, filename) do
-    case OXC.parse(source, filename) do
-      {:ok, ast} ->
-        {:ok, ast |> collect_test_starts() |> Enum.sort() |> Enum.map(&line(source, &1))}
-
-      {:error, _} = error ->
-        error
+    with {:ok, ast} <- OXC.parse(source, filename),
+         {:ok, groups} <- collect_test_groups(ast) do
+      {:ok, lines(source, flatten_groups(groups))}
     end
   end
 
-  defp collect_test_starts(ast) do
-    {_ast, starts} =
-      OXC.postwalk(ast, [], fn
-        %{type: :call_expression, callee: callee, arguments: args} = node, starts
+  # A group is `{anchor, starts}`: the offset of a test declaration and the
+  # offsets of the tests it registers, in registration order. Post-order
+  # traversal reaches the tests inside a `describe.each` body before the
+  # `describe.each` call, which then folds their groups into one repeated group.
+  defp collect_test_groups(ast) do
+    {_ast, acc} =
+      OXC.postwalk(ast, {:ok, []}, fn
+        %{type: :call_expression, callee: callee, arguments: args} = node, {:ok, groups}
         when is_list(args) ->
-          if test_callee?(callee) and test_call?(args) do
-            {node, [node.start | starts]}
-          else
-            {node, starts}
-          end
-
-        node, starts ->
-          {node, starts}
+          {node, add_test_group(node, callee, args, groups)}
+
+        node, acc ->
+          {node, acc}
       end)
 
-    starts
+    acc
+  end
+
+  defp add_test_group(node, callee, args, groups) do
+    cond do
+      test_callee?(callee) and test_call?(args) ->
+        {:ok, [{node.start, [node.start]} | groups]}
+
+      each_callee?(callee, &test_callee?/1) and test_call?(args) ->
+        with {:ok, count} <- case_count(callee) do
+          {:ok, [{node.start, List.duplicate(node.start, count)} | groups]}
+        end
+
+      each_callee?(callee, &describe_callee?/1) ->
+        with {:ok, count} <- case_count(callee) do
+          {inner, outer} =
+            Enum.split_with(groups, fn {anchor, _starts} ->
+              anchor > node.start and anchor < node.end
+            end)
+
+          starts = inner |> flatten_groups() |> List.duplicate(count) |> Enum.concat()
+          {:ok, [{node.start, starts} | outer]}
+        end
+
+      true ->
+        {:ok, groups}
+    end
+  end
+
+  defp flatten_groups(groups) do
+    groups |> Enum.sort() |> Enum.flat_map(fn {_anchor, starts} -> starts end)
+  end
+
+  @test_names ["test", "it"]
+  @describe_names ["describe"]
+
+  defp test_callee?(callee), do: callee_named?(callee, @test_names)
+  defp describe_callee?(callee), do: callee_named?(callee, @describe_names)
+
+  # `test`, `test.skip`, `test.todo`, and the same for `it` and `describe`.
+  defp callee_named?(%{type: :identifier, name: name}, names), do: name in names
+
+  defp callee_named?(%{type: :member_expression, object: object, property: property}, names) do
+    property[:name] in ["skip", "todo"] and callee_named?(object, names)
   end
 
-  defp test_callee?(%{type: :identifier, name: name}) when name in ["test", "it"], do: true
+  defp callee_named?(_callee, _names), do: false
 
-  defp test_callee?(%{type: :member_expression, object: object, property: %{name: property}})
-       when property in ["skip", "todo"] do
-    test_callee?(object)
+  # `test.each(cases)` and `describe.each(cases)`, whose result is then called
+  # with the name and body.
+  defp each_callee?(
+         %{type: :call_expression, callee: %{type: :member_expression} = callee},
+         base?
+       ) do
+    callee.property[:name] == "each" and base?.(callee.object)
   end
 
-  defp test_callee?(_), do: false
+  defp each_callee?(_callee, _base?), do: false
+
+  defp case_count(%{arguments: [%{type: :array_expression, elements: elements}]}),
+    do: {:ok, length(elements)}
+
+  defp case_count(_each_call), do: {:error, :dynamic_cases}
 
   defp test_call?([%{value: name} | _]) when is_binary(name), do: true
   defp test_call?([%{type: :template_literal, expressions: [], quasis: [_]} | _]), do: true
   defp test_call?(_), do: false
 
-  defp line(source, start) do
-    source
-    |> binary_part(0, start)
-    |> count_newlines(1)
-  end
+  # Counts each newline once for all offsets. Counting from the start of the
+  # source per test is quadratic and dominated the cost on large files.
+  defp lines(source, starts) do
+    newlines = for {offset, _length} <- :binary.matches(source, "\n"), do: offset
 
-  defp count_newlines(<<>>, line), do: line
-  defp count_newlines(<<?\n, rest::binary>>, line), do: count_newlines(rest, line + 1)
-  defp count_newlines(<<_byte, rest::binary>>, line), do: count_newlines(rest, line)
+    {line_by_start, _rest, _line} =
+      starts
+      |> Enum.uniq()
+      |> Enum.sort()
+      |> Enum.reduce({%{}, newlines, 1}, fn start, {lines, newlines, line} ->
+        {before, rest} = Enum.split_while(newlines, &(&1 < start))
+        line = line + length(before)
+        {Map.put(lines, start, line), rest, line}
+      end)
+
+    Enum.map(starts, &Map.fetch!(line_by_start, &1))
+  end
 end
diff --git a/lib/volt/test/plugin.ex b/lib/volt/test/plugin.ex
index 455e47b..0bcd950 100644
--- a/lib/volt/test/plugin.ex
+++ b/lib/volt/test/plugin.ex
@@ -46,10 +46,15 @@ defmodule Volt.Test.Plugin do
 
   def load(@test_entry, opts) do
     imports =
-      Stream.concat(Keyword.fetch!(opts, :setup_files), [Keyword.fetch!(opts, :test_file)])
+      opts
+      |> Keyword.fetch!(:setup_files)
+      |> Stream.concat([Keyword.fetch!(opts, :test_file)])
+      |> Enum.map(&"import #{inspect(&1)};")
 
-    source = Enum.map_join(imports, "\n", &"import #{inspect(&1)};")
-    {:ok, source <> "\n"}
+    source =
+      Volt.Priv.render!({:volt, "ts"}, "test/entry.ts", [], splices: [imports: imports])
+
+    {:ok, source}
   end
 
   def load(specifier, _opts), do: load(specifier)
diff --git a/lib/volt/test/result.ex b/lib/volt/test/result.ex
index b293afb..4358513 100644
--- a/lib/volt/test/result.ex
+++ b/lib/volt/test/result.ex
@@ -3,7 +3,7 @@ defmodule Volt.Test.Result do
 
   defmodule Metadata do
     @moduledoc "Metadata collected for a registered JavaScript test before execution."
-    use JSONCodec, case: :camel, fast_path: :json
+    use JSONCodec, case: :camel
 
     defstruct [:id, :name, :full_name, :suite, :mode, :skip_reason, tags: [], line: nil]
 
@@ -21,7 +21,7 @@ defmodule Volt.Test.Result do
 
   defmodule SerializedError do
     @moduledoc "Serialized JavaScript error details returned by a failed test."
-    use JSONCodec, fast_path: :json
+    use JSONCodec
 
     defstruct [:name, :message, :stack, :expected, :actual]
 
@@ -36,7 +36,7 @@ defmodule Volt.Test.Result do
 
   defmodule Test do
     @moduledoc "Execution result for one registered JavaScript test."
-    use JSONCodec, case: :camel, fast_path: :json
+    use JSONCodec, case: :camel
 
     defstruct [:id, :name, :full_name, :status, :duration, :error, :skip_reason]
 
@@ -51,7 +51,7 @@ defmodule Volt.Test.Result do
           }
   end
 
-  use JSONCodec, fast_path: :json
+  use JSONCodec
 
   defstruct [:file, :status, :duration, :total, :failed, :skipped, tests: []]
 
diff --git a/lib/volt/test/shared.ex b/lib/volt/test/shared.ex
index d8eb238..42312d9 100644
--- a/lib/volt/test/shared.ex
+++ b/lib/volt/test/shared.ex
@@ -3,15 +3,20 @@ defmodule Volt.Test.Shared do
 
   alias Volt.Test.Config
 
+  @doc """
+  Add source lines to collected tests.
+
+  Lines are read from the source and matched to tests by position. Tests keep
+  no line when the source declares a different number of tests than the runtime
+  collected, for example when they are registered in a loop.
+  """
   def add_source_lines(path, tests) do
     with {:ok, source} <- File.read(path),
-         {:ok, lines} <- Volt.Test.Lines.test_lines(source, Path.basename(path)) do
-      {:ok,
-       tests
-       |> Enum.zip(lines)
-       |> Enum.map(fn {test, line} -> %{test | line: line} end)}
+         {:ok, lines} <- Volt.Test.Lines.test_lines(source, Path.basename(path)),
+         true <- length(lines) == length(tests) do
+      {:ok, Enum.zip_with(tests, lines, fn test, line -> %{test | line: line} end)}
     else
-      {:error, _} -> {:ok, tests}
+      _ -> {:ok, tests}
     end
   end
 
diff --git a/lib/volt/test/sigils.ex b/lib/volt/test/sigils.ex
index a262c61..e17143b 100644
--- a/lib/volt/test/sigils.ex
+++ b/lib/volt/test/sigils.ex
@@ -63,8 +63,13 @@ defmodule Volt.Test.Sigils do
 
   defp validate!(source, filename) do
     case OXC.parse(source, filename) do
-      {:ok, _ast} -> :ok
-      {:error, errors} -> raise ArgumentError, "invalid #{filename} source: #{inspect(errors)}"
+      {:ok, _ast} ->
+        :ok
+
+      {:error, errors} ->
+        raise ArgumentError,
+              "invalid #{filename} source:\n" <>
+                Enum.map_join(errors, "\n", &OXC.Diagnostic.format/1)
     end
   end
 end
diff --git a/lib/volt/watcher.ex b/lib/volt/watcher.ex
index 8a57dcd..37625a2 100644
--- a/lib/volt/watcher.ex
+++ b/lib/volt/watcher.ex
@@ -17,10 +17,16 @@ defmodule Volt.Watcher do
     * `:root` — asset source directory (required, e.g. `"assets"`)
     * `:watch_dirs` — additional directories to watch for Tailwind scanning
       (e.g. `["lib/"]` for `.ex`/`.heex` templates)
-    * `:reload_dirs` — additional directories whose changes trigger a full
-      browser reload without being compiled by Volt
+    * `:reload_dirs` — additional directories of templates and content that
+      Volt does not compile. A change asks open pages to revalidate their
+      HTML and reload if it changed; see `Volt.HMR.Document`
+    * `:watch_ignored` — paths or glob patterns excluded from watcher events
+      (default: common VCS, dependency, test-output, cache, and build directories)
     * `:tailwind` — enable Tailwind CSS rebuilds (default: `false`)
     * `:tailwind_css` — custom Tailwind input CSS (default: Tailwind base)
+    * `:tailwind_sources` — source globs scanned for Tailwind candidates
+    * `:tailwind_name` — logical Tailwind output name (default: input basename)
+    * `:tailwind_url` — browser URL broadcast for Tailwind style updates
     * `:target` — JS downlevel target
     * `:import_source` — JSX import source
     * `:vapor` — Vue Vapor mode
@@ -31,6 +37,7 @@ defmodule Volt.Watcher do
   alias Volt.HMR
   alias Volt.HMR.StyleGraph
   alias Volt.JS.Extensions
+  alias Volt.Paths
 
   @dialyzer {:nowarn_function, detect_changes: 2}
 
@@ -42,14 +49,25 @@ defmodule Volt.Watcher do
   defstruct [
     :root,
     :config,
+    :owner_monitor,
+    :managed_key,
+    :tables,
+    session: :default,
     fs_pids: [],
     pending: %{},
     tailwind_timer: nil,
+    pending_reloads: [],
     tailwind_changed: [],
     tailwind_full?: false,
     tailwind_outdir: nil,
+    discovered_watches: %{},
+    base_watch_dirs: [],
     tailwind_dirs: [],
-    reload_dirs: []
+    reload_dirs: [],
+    explicit_ignored: [],
+    watch_ignored: [],
+    linked_dirs: [],
+    source_digests: %{}
   ]
 
   def start_link(opts) do
@@ -61,66 +79,200 @@ defmodule Volt.Watcher do
 
   @impl true
   def init(opts) do
-    root = Keyword.fetch!(opts, :root) |> Path.expand()
-    watch_dirs = Keyword.get(opts, :watch_dirs, []) |> Enum.map(&Path.expand/1)
-    reload_dirs = Keyword.get(opts, :reload_dirs, []) |> Enum.map(&Path.expand/1)
+    Process.flag(:trap_exit, true)
+
+    owner_monitor =
+      case Keyword.get(opts, :owner) do
+        nil -> nil
+        owner when is_pid(owner) -> Process.monitor(owner)
+      end
+
+    root = Keyword.fetch!(opts, :root) |> Paths.expand()
+    watch_dirs = Keyword.get(opts, :watch_dirs, []) |> Enum.map(&Paths.expand/1)
+    reload_dirs = Keyword.get(opts, :reload_dirs, []) |> Enum.map(&Paths.expand/1)
     tailwind_outdir = Keyword.get(opts, :tailwind_outdir) |> maybe_expand()
+    tailwind_name = Keyword.get(opts, :tailwind_name, "app")
+    tailwind_url = Keyword.get(opts, :tailwind_url, "/assets/css/#{tailwind_name}.css")
+    session = Keyword.get(opts, :session, :default)
+    tailwind_key = Keyword.get(opts, :tailwind_key, {:watcher, root})
+
+    tailwind_key =
+      if session == :default, do: tailwind_key, else: {:session, session, tailwind_key}
+
+    configured_tailwind_sources = Keyword.get(opts, :tailwind_sources)
 
     config =
       opts
-      |> Keyword.drop([:root, :name, :watch_dirs, :reload_dirs, :tailwind_outdir])
+      |> Keyword.drop([
+        :root,
+        :name,
+        :session,
+        :owner,
+        :managed_key,
+        :tables,
+        :watch_dirs,
+        :reload_dirs,
+        :watch_ignored,
+        :tailwind_key,
+        :tailwind_name,
+        :tailwind_sources,
+        :tailwind_url,
+        :tailwind_outdir
+      ])
       |> Map.new()
 
-    all_dirs = Enum.uniq([root | watch_dirs ++ reload_dirs ++ tailwind_colocated_dirs(config)])
+    source_dirs =
+      if config[:tailwind] do
+        Enum.map(configured_tailwind_sources || [], &Paths.expand(&1.base))
+      else
+        []
+      end
+
+    all_dirs =
+      Enum.uniq([
+        root | watch_dirs ++ reload_dirs ++ source_dirs ++ tailwind_colocated_dirs(config)
+      ])
+
+    tailwind_sources = configured_tailwind_sources || watcher_sources(all_dirs)
+    watch_ignored = Volt.Watcher.Ignore.compile(Keyword.get(opts, :watch_ignored, []), all_dirs)
+
+    # Linked packages change in place, where no lockfile records it, and the
+    # vendor pre-bundle has to follow.
+    linked_dirs =
+      root |> NPM.Resolution.PackageResolver.find_node_modules() |> Volt.JS.Package.linked_dirs()
 
     fs_pids =
-      Enum.map(all_dirs, fn dir ->
+      Enum.map(all_dirs ++ linked_dirs, fn dir ->
         {:ok, pid} = FileSystem.start_link(dirs: [dir])
         FileSystem.subscribe(pid)
         pid
       end)
 
+    config =
+      config
+      |> Map.put(:tailwind_key, tailwind_key)
+      |> Map.put(:tailwind_name, tailwind_name)
+      |> Map.put(:tailwind_configured_sources, tailwind_sources)
+      |> Map.put(:tailwind_sources, tailwind_sources)
+      |> Map.put(:tailwind_url, tailwind_url)
+
     state = %__MODULE__{
       root: root,
+      owner_monitor: owner_monitor,
+      tables: Keyword.get(opts, :tables),
+      managed_key: Keyword.get(opts, :managed_key),
+      session: Keyword.get(opts, :session, :default),
       fs_pids: fs_pids,
       config: config,
       tailwind_outdir: tailwind_outdir,
+      base_watch_dirs: all_dirs,
       tailwind_dirs: all_dirs,
-      reload_dirs: reload_dirs
+      reload_dirs: reload_dirs,
+      explicit_ignored:
+        Volt.Watcher.Ignore.compile_explicit(Keyword.get(opts, :watch_ignored, []), all_dirs),
+      watch_ignored: watch_ignored,
+      linked_dirs: linked_dirs
     }
 
-    if config[:tailwind] do
-      initial_tailwind_build(all_dirs, config[:tailwind_css], tailwind_outdir)
-    end
+    state = %{state | source_digests: initial_source_digests(all_dirs -- [root], state)}
+
+    if config[:tailwind], do: initial_tailwind_build(state)
+
+    {:ok, refresh_tailwind_inputs(state)}
+  end
+
+  defp refresh_tailwind_inputs(%{config: %{tailwind: true, tailwind_worker: worker}} = state)
+       when not is_nil(worker) do
+    inputs = Volt.Tailwind.Worker.inputs(worker)
+
+    dirs =
+      Enum.uniq(
+        Enum.map(inputs.sources, &Path.expand(&1.base)) ++
+          Enum.map(inputs.dependencies, &Path.dirname/1)
+      )
+
+    desired =
+      dirs
+      |> Enum.map(&existing_watch_parent/1)
+      |> Enum.uniq()
+      |> Enum.reject(&(&1 in state.base_watch_dirs))
+
+    {kept, removed} = Map.split(state.discovered_watches, desired)
+
+    Enum.each(removed, fn {_dir, pid} ->
+      if Process.alive?(pid), do: GenServer.stop(pid)
+    end)
+
+    added =
+      Map.new(desired -- Map.keys(kept), fn dir ->
+        {:ok, pid} = FileSystem.start_link(dirs: [dir])
+        FileSystem.subscribe(pid)
+        {dir, pid}
+      end)
+
+    watches = Map.merge(kept, added)
 
-    {:ok, state}
+    config =
+      state.config
+      |> Map.put(:tailwind_sources, inputs.sources)
+      |> Map.put(:tailwind_dependencies, inputs.dependencies)
+
+    %{
+      state
+      | config: config,
+        discovered_watches: watches,
+        fs_pids: (state.fs_pids -- Map.values(removed)) ++ Map.values(added),
+        tailwind_dirs: state.base_watch_dirs ++ Map.keys(watches)
+    }
+  end
+
+  defp refresh_tailwind_inputs(state), do: state
+
+  defp existing_watch_parent(path) do
+    parent = Path.dirname(path)
+    if File.dir?(path) or parent == path, do: path, else: existing_watch_parent(parent)
   end
 
-  defp initial_tailwind_build(dirs, css_path, outdir) do
-    case build_tailwind(dirs, css_path, outdir) do
+  defp watcher_sources(dirs), do: Enum.map(dirs, &%{base: &1, pattern: "**/*"})
+
+  defp initial_tailwind_build(%{config: config} = state) do
+    case build_tailwind(
+           config.tailwind_sources,
+           config[:tailwind_css],
+           state.tailwind_outdir,
+           config.tailwind_key,
+           config.tailwind_name,
+           config[:tailwind_runtime],
+           config[:tailwind_worker]
+         ) do
       {:ok, css} ->
         Logger.debug("[Volt] Initial Tailwind build: #{byte_size(css)} bytes")
 
       {:error, reason} ->
         Logger.warning("[Volt] Initial Tailwind build failed: #{inspect(reason)}")
+        tailwind_error(reason, state)
     end
   end
 
-  defp build_tailwind(dirs, css_path, outdir) do
-    sources = Enum.map(dirs, &%{base: &1, pattern: "**/*"})
+  defp build_tailwind(sources, css_path, outdir, key, name, runtime, worker) do
+    worker_opts = if worker, do: [worker: worker], else: [key: key, runtime: runtime]
 
     with {:ok, {css_input, css_base}} <- read_tailwind_css(css_path),
-         {:ok, css} <- Volt.Tailwind.build(sources: sources, css: css_input, css_base: css_base) do
-      if outdir do
-        File.mkdir_p!(outdir)
-        File.write!(Path.join(outdir, "app.css"), css)
-      end
-
+         {:ok, css} <-
+           Volt.Tailwind.build(
+             worker_opts ++
+               [
+                 sources: sources,
+                 css: css_input,
+                 css_base: css_base
+               ]
+           ) do
+      Volt.Tailwind.Artifact.write(outdir, name, css)
       {:ok, css}
     end
   end
 
-  defp read_tailwind_css(nil), do: {:ok, {nil, File.cwd!()}}
+  defp read_tailwind_css(nil), do: {:ok, {nil, Paths.root()}}
 
   defp read_tailwind_css(path) do
     case File.read(path) do
@@ -131,18 +283,37 @@ defmodule Volt.Watcher do
 
   @impl true
   def handle_info({:file_event, _pid, {path, events}}, state) do
-    if relevant_write_event?(events) do
+    path = Volt.Watcher.Path.normalize_from_roots(path, state.tailwind_dirs ++ state.linked_dirs)
+
+    if relevant_write_event?(events) and not ignored_path?(path, state) do
       ext = Path.extname(path)
 
       cond do
         tailwind_output?(path, state) ->
           {:noreply, state}
 
+        linked_package_path?(path, state) ->
+          # The package is bundled again on the next request, under a new
+          # vendor URL, which the page has to load from the start.
+          Volt.Dev.Prebundled.forget()
+          relative = Path.relative_to(path, state.root)
+          HMR.broadcast(:update, %{path: relative, changes: [:vendor]}, session: state.session)
+          {:noreply, state}
+
+        path in Map.get(state.config, :tailwind_dependencies, []) ->
+          {:noreply, maybe_schedule_tailwind(state, path, full?: true)}
+
+        reload_path?(path, state) and state.config[:tailwind] ->
+          state = %{state | pending_reloads: Enum.uniq([path | state.pending_reloads])}
+          {:noreply, maybe_schedule_tailwind(state, path)}
+
         ext in Extensions.css() ->
           state = handle_css_change(path, state)
           {:noreply, state}
 
         ext in Extensions.watchable_js(state.config[:plugins] || []) ->
+          # The change may add an import of a package that is not bundled yet.
+          Volt.Dev.Prebundled.forget()
           state = schedule_rebuild(state, path)
           state = maybe_schedule_tailwind(state, path)
           {:noreply, state}
@@ -156,8 +327,11 @@ defmodule Volt.Watcher do
           {:noreply, state}
 
         reload_path?(path, state) ->
-          handle_reload_change(path)
-          {:noreply, state}
+          handle_reload_change(path, state)
+          {:noreply, maybe_schedule_tailwind(state, path)}
+
+        tailwind_source?(path, state) ->
+          {:noreply, maybe_schedule_tailwind(state, path)}
 
         true ->
           {:noreply, state}
@@ -169,22 +343,49 @@ defmodule Volt.Watcher do
 
   def handle_info({:rebuild, path}, state) do
     state = %{state | pending: Map.delete(state.pending, path)}
-    handle_js_change(path, state)
-    {:noreply, state}
+    digest = source_digest(path)
+
+    # Generators such as Phoenix colocated hooks rewrite files with identical
+    # content on every code reload; rebuilding for those would reload the page,
+    # which triggers the next rewrite.
+    if Map.fetch(state.source_digests, path) == {:ok, digest} do
+      {:noreply, state}
+    else
+      handle_js_change(path, state)
+      {:noreply, %{state | source_digests: Map.put(state.source_digests, path, digest)}}
+    end
   end
 
   def handle_info(:tailwind_rebuild, state) do
     changed = state.tailwind_changed
     full? = state.tailwind_full?
     state = %{state | tailwind_timer: nil, tailwind_changed: [], tailwind_full?: false}
-    handle_tailwind_rebuild(changed, full?, state)
-    {:noreply, state}
+
+    case handle_tailwind_rebuild(changed, full?, state) do
+      :ok ->
+        Enum.each(state.pending_reloads, &handle_reload_change(&1, state))
+        {:noreply, refresh_tailwind_inputs(%{state | pending_reloads: []})}
+
+      {:error, _reason} ->
+        {:noreply, refresh_tailwind_inputs(%{state | tailwind_full?: true})}
+    end
   end
 
   def handle_info({:file_event, _pid, :stop}, state) do
     {:noreply, state}
   end
 
+  def handle_info({:DOWN, ref, :process, _pid, _reason}, %{owner_monitor: ref} = state)
+      when is_reference(ref) do
+    {:stop, :normal, state}
+  end
+
+  def handle_info({:EXIT, pid, reason}, state) do
+    if pid in state.fs_pids,
+      do: {:stop, {:filesystem_watcher_exit, reason}, state},
+      else: {:noreply, state}
+  end
+
   def handle_info({:DOWN, _ref, :process, _pid, _reason}, state) do
     {:noreply, state}
   end
@@ -193,6 +394,55 @@ defmodule Volt.Watcher do
     Enum.any?(@write_events, &(&1 in events))
   end
 
+  defp linked_package_path?(path, %{linked_dirs: dirs}),
+    do: Enum.any?(dirs, &Volt.Path.inside?(path, &1))
+
+  defp ignored_path?(path, state) do
+    patterns =
+      if path in Map.get(state.config, :tailwind_dependencies, []),
+        do: state.explicit_ignored,
+        else: state.watch_ignored
+
+    Enum.any?(patterns, &GlobEx.match?(&1, path))
+  end
+
+  defp source_digest(path) do
+    case File.read(path) do
+      {:ok, source} -> :crypto.hash(:sha256, source)
+      {:error, _reason} -> :missing
+    end
+  end
+
+  # Directories outside the asset root hold generated sources whose first
+  # rewrite would otherwise have no baseline to compare against.
+  defp initial_source_digests(dirs, state) do
+    extensions = Extensions.watchable_js(state.config[:plugins] || [])
+
+    for dir <- dirs,
+        path <- source_files(dir, extensions, state),
+        into: %{},
+        do: {path, source_digest(path)}
+  end
+
+  defp source_files(dir, extensions, state) do
+    case File.ls(dir) do
+      {:ok, names} ->
+        Enum.flat_map(names, fn name ->
+          path = Path.join(dir, name)
+
+          cond do
+            ignored_path?(path, state) -> []
+            File.dir?(path) -> source_files(path, extensions, state)
+            Path.extname(path) in extensions -> [path]
+            true -> []
+          end
+        end)
+
+      {:error, _reason} ->
+        []
+    end
+  end
+
   defp schedule_rebuild(state, path) do
     case Map.get(state.pending, path) do
       nil -> :ok
@@ -222,40 +472,60 @@ defmodule Volt.Watcher do
   defp handle_js_change(path, state) do
     relative = Path.relative_to(path, state.root)
     css? = css_file?(path)
-    css_dependents = if css?, do: Volt.HMR.StyleGraph.dependents(path), else: []
 
-    old_entry = Volt.Cache.get_file(path)
-    Volt.Cache.evict_file(path)
-    Volt.HMR.ModuleGraph.invalidate_file(path)
+    css_dependents =
+      if css?, do: Volt.HMR.StyleGraph.dependents(path, state.tables || state.session), else: []
+
+    old_entry = Volt.Cache.get_file(path, state.tables || state.session)
+    Volt.Cache.evict_file(path, state.tables || state.session)
+
+    Volt.HMR.ModuleGraph.invalidate_file(
+      path,
+      System.system_time(:millisecond),
+      state.tables || state.session
+    )
 
     case File.read(path) do
       {:ok, source} ->
         case Volt.Pipeline.compile(path, source, Map.to_list(state.config)) do
           {:ok, result} ->
-            Volt.HMR.GlobGraph.update_from_source(path, source)
-            Volt.HMR.ImportGraph.update_from_compiled(path, result.code)
-
-            Volt.HMR.StyleDependencies.update_from_compile(path, source, result)
-
+            Volt.HMR.GlobGraph.update_from_source(path, source, state.tables || state.session)
+
+            Volt.HMR.ImportGraph.update_from_compiled(
+              path,
+              result.code,
+              state.tables || state.session
+            )
+
+            Volt.HMR.StyleDependencies.update_from_compile(
+              path,
+              source,
+              result,
+              state.tables || state.session
+            )
+
+            HMR.clear_error(path, session: state.session)
             changes = if css?, do: [:style], else: detect_changes(old_entry, result)
-            broadcast_change(path, relative, changes, state.root)
-            broadcast_css_dependents(css_dependents, state.root)
-            broadcast_glob_dependents(path, state.root)
+            broadcast_change(path, relative, changes, state)
+            broadcast_css_dependents(css_dependents, state)
+            broadcast_glob_dependents(path, state)
 
           {:error, reason} ->
-            HMR.broadcast(:error, %{path: relative, reason: reason})
+            HMR.error(path, reason, session: state.session)
         end
 
       {:error, reason} when reason in [:enoent, :eacces, :eperm] ->
-        Volt.HMR.ImportGraph.remove(path)
-        Volt.HMR.GlobGraph.remove(path)
-        if css?, do: Volt.HMR.StyleGraph.remove(path)
-        Volt.HMR.ModuleGraph.remove_file(path)
-        HMR.update(relative, [:full])
-        broadcast_glob_dependents(path, state.root)
+        Volt.HMR.ImportGraph.remove(path, state.tables || state.session)
+        Volt.HMR.GlobGraph.remove(path, state.tables || state.session)
+        if css?, do: Volt.HMR.StyleGraph.remove(path, state.tables || state.session)
+        Volt.HMR.ModuleGraph.remove_file(path, state.tables || state.session)
+        HMR.clear_error(path, session: state.session)
+        HMR.update(relative, [:full], session: state.session)
+        broadcast_glob_dependents(path, state)
 
       {:error, reason} ->
-        HMR.broadcast(:error, %{path: relative, reason: inspect(reason)})
+        message = "Could not read #{relative}: #{:file.format_error(reason)}"
+        HMR.error(path, message, session: state.session)
     end
   end
 
@@ -263,23 +533,33 @@ defmodule Volt.Watcher do
 
   defp handle_css_change(path, state) do
     relative = Path.relative_to(path, state.root)
-    css_dependents = StyleGraph.dependents(path)
+    css_dependents = StyleGraph.dependents(path, state.tables || state.session)
     tailwind_input? = tailwind_input?(path, state)
 
-    Volt.Cache.evict_file(path)
-    Volt.HMR.ModuleGraph.invalidate_file(path)
+    Volt.Cache.evict_file(path, state.tables || state.session)
+
+    Volt.HMR.ModuleGraph.invalidate_file(
+      path,
+      System.system_time(:millisecond),
+      state.tables || state.session
+    )
 
     if File.regular?(path) do
       source = File.read!(path)
-      StyleGraph.update(path, Volt.CSS.Dependencies.resolve(source, path))
+
+      StyleGraph.update(
+        path,
+        Volt.CSS.Dependencies.resolve(source, path),
+        state.tables || state.session
+      )
     else
-      StyleGraph.remove(path)
+      StyleGraph.remove(path, state.tables || state.session)
     end
 
     if Volt.Path.inside?(path, state.root) and not tailwind_input? do
-      HMR.broadcast(:update, %{path: relative, changes: [:style]})
-      broadcast_css_dependents(css_dependents, state.root)
-      broadcast_glob_dependents(path, state.root)
+      HMR.broadcast(:update, %{path: relative, changes: [:style]}, session: state.session)
+      broadcast_css_dependents(css_dependents, state)
+      broadcast_glob_dependents(path, state)
     end
 
     maybe_schedule_tailwind(state, path, full?: true)
@@ -295,48 +575,60 @@ defmodule Volt.Watcher do
   defp tailwind_output?(_path, %{tailwind_outdir: nil}), do: false
   defp tailwind_output?(path, state), do: Volt.Path.inside?(path, state.tailwind_outdir)
 
-  defp broadcast_css_dependents(dependents, root) do
+  defp broadcast_css_dependents(dependents, state) do
     dependents
     |> Enum.uniq()
     |> Enum.each(fn importer ->
-      Volt.Cache.evict_file(importer)
-      Volt.HMR.ModuleGraph.invalidate_file(importer)
-      relative = Path.relative_to(importer, root)
-      HMR.broadcast(:update, %{path: relative, changes: [:style]})
+      Volt.Cache.evict_file(importer, state.tables || state.session)
+
+      Volt.HMR.ModuleGraph.invalidate_file(
+        importer,
+        System.system_time(:millisecond),
+        state.session
+      )
+
+      relative = Path.relative_to(importer, state.root)
+      HMR.broadcast(:update, %{path: relative, changes: [:style]}, session: state.session)
     end)
   end
 
-  defp handle_reload_change(path) do
-    path = Path.relative_to_cwd(path)
-    HMR.full_reload(path)
+  defp handle_reload_change(path, state) do
+    path = Path.relative_to(path, Paths.root())
+    HMR.document_update(path, session: state.session)
   end
 
   defp handle_asset_change(path, state) do
     relative = Path.relative_to(path, state.root)
-    css_dependents = Volt.HMR.StyleGraph.dependents(path)
+    css_dependents = Volt.HMR.StyleGraph.dependents(path, state.tables || state.session)
+
+    Volt.Cache.evict_file(path, state.tables || state.session)
 
-    Volt.Cache.evict_file(path)
-    Volt.HMR.ModuleGraph.invalidate_file(path)
-    HMR.broadcast(:update, %{path: relative, changes: [:full]})
-    broadcast_css_dependents(css_dependents, state.root)
-    broadcast_glob_dependents(path, state.root)
+    Volt.HMR.ModuleGraph.invalidate_file(
+      path,
+      System.system_time(:millisecond),
+      state.tables || state.session
+    )
+
+    HMR.broadcast(:update, %{path: relative, changes: [:full]}, session: state.session)
+    broadcast_css_dependents(css_dependents, state)
+    broadcast_glob_dependents(path, state)
   end
 
-  defp broadcast_glob_dependents(path, root) do
+  defp broadcast_glob_dependents(path, state) do
     path
-    |> Volt.HMR.GlobGraph.dependents()
+    |> Volt.HMR.GlobGraph.dependents(state.tables || state.session)
     |> Enum.reject(&(&1 == path))
     |> Enum.each(fn importer ->
-      Volt.Cache.evict_file(importer)
-      relative = Path.relative_to(importer, root)
-      HMR.broadcast(:update, %{path: relative, changes: [:full]})
+      Volt.Cache.evict_file(importer, state.tables || state.session)
+      relative = Path.relative_to(importer, state.root)
+      HMR.broadcast(:update, %{path: relative, changes: [:full]}, session: state.session)
     end)
   end
 
-  defp broadcast_change(path, relative, changes, root) do
+  defp broadcast_change(path, relative, changes, state) do
     cond do
       changes == [:style] ->
-        HMR.broadcast(:update, %{path: relative, changes: [:style]})
+        HMR.broadcast(:update, %{path: relative, changes: [:style]}, session: state.session)
 
       changes == [] ->
         :ok
@@ -349,32 +641,54 @@ defmodule Volt.Watcher do
           end
         end
 
-        case Volt.HMR.Boundary.find_boundary(path, read_source) do
+        case Volt.HMR.Boundary.find_boundary(path, read_source, state.tables || state.session) do
           {:ok, boundary_path} ->
             timestamp = System.system_time(:millisecond)
-            boundary_relative = Path.relative_to(boundary_path, root)
-
-            HMR.broadcast(:update, %{
-              path: relative,
-              changes: [:hmr],
-              boundary: boundary_relative,
-              timestamp: timestamp
-            })
+            boundary_relative = Path.relative_to(boundary_path, state.root)
+
+            HMR.broadcast(
+              :update,
+              %{
+                path: relative,
+                changes: [:hmr],
+                boundary: boundary_relative,
+                timestamp: timestamp
+              },
+              session: state.session
+            )
 
           :full_reload ->
-            HMR.broadcast(:update, %{path: relative, changes: changes})
+            HMR.broadcast(:update, %{path: relative, changes: changes}, session: state.session)
         end
     end
   end
 
   defp handle_tailwind_rebuild(_changed_paths, true, state) do
-    case build_tailwind(state.tailwind_dirs, state.config[:tailwind_css], state.tailwind_outdir) do
+    previous = previous_stylesheet(state)
+
+    case build_tailwind(
+           state.config.tailwind_configured_sources,
+           state.config[:tailwind_css],
+           state.tailwind_outdir,
+           state.config.tailwind_key,
+           state.config.tailwind_name,
+           state.config[:tailwind_runtime],
+           state.config[:tailwind_worker]
+         ) do
       {:ok, css} ->
-        HMR.broadcast(:update, %{path: "assets/css/app.css", changes: [:style]})
+        clear_tailwind_error(state)
+
+        if previous != {:ok, css} do
+          HMR.broadcast(:update, %{path: state.config.tailwind_url, changes: [:style]},
+            session: state.session
+          )
+        end
+
         Logger.debug("[Volt] Tailwind rebuilt (#{byte_size(css)} bytes)")
+        :ok
 
       {:error, reason} ->
-        HMR.broadcast(:error, %{path: "tailwind", reason: inspect(reason)})
+        tailwind_error(reason, state)
     end
   end
 
@@ -385,24 +699,61 @@ defmodule Volt.Watcher do
         %{file: path, extension: ext}
       end)
 
-    with {:ok, {css_input, css_base}} <- read_tailwind_css(state.config[:tailwind_css]),
-         {:ok, css} <- Volt.Tailwind.rebuild(changed, css: css_input, css_base: css_base) do
-      if outdir = state.tailwind_outdir do
-        File.mkdir_p!(outdir)
-        File.write!(Path.join(outdir, "app.css"), css)
+    worker_opts =
+      case state.config[:tailwind_worker] do
+        nil -> [key: state.config.tailwind_key]
+        worker -> [worker: worker]
       end
 
-      HMR.broadcast(:update, %{path: "assets/css/app.css", changes: [:style]})
+    with {:ok, {css_input, css_base}} <- read_tailwind_css(state.config[:tailwind_css]),
+         {:ok, css} <-
+           Volt.Tailwind.rebuild(
+             changed,
+             worker_opts ++
+               [
+                 css: css_input,
+                 css_base: css_base
+               ]
+           ) do
+      Volt.Tailwind.Artifact.write(state.tailwind_outdir, state.config.tailwind_name, css)
+      clear_tailwind_error(state)
+
+      HMR.broadcast(:update, %{path: state.config.tailwind_url, changes: [:style]},
+        session: state.session
+      )
+
       Logger.debug("[Volt] Tailwind rebuilt (#{byte_size(css)} bytes)")
+      :ok
     else
       :unchanged ->
         :ok
 
       {:error, reason} ->
-        HMR.broadcast(:error, %{path: "tailwind", reason: inspect(reason)})
+        tailwind_error(reason, state)
     end
   end
 
+  defp previous_stylesheet(state) do
+    worker =
+      state.config[:tailwind_worker] ||
+        case Registry.lookup(Volt.Tailwind.Registry, state.config.tailwind_key) do
+          [{pid, _}] -> pid
+          [] -> nil
+        end
+
+    if worker, do: Volt.Tailwind.Worker.stylesheet(worker), else: {:error, :not_built}
+  end
+
+  defp tailwind_error(reason, state) do
+    HMR.error(tailwind_error_path(state), reason, session: state.session)
+    {:error, reason}
+  end
+
+  defp clear_tailwind_error(state),
+    do: HMR.clear_error(tailwind_error_path(state), session: state.session)
+
+  defp tailwind_error_path(state), do: state.config[:tailwind_css] || "tailwind"
+
   defp detect_changes(nil, _new), do: [:full]
 
   defp detect_changes(old_entry, new_result) do
@@ -419,6 +770,17 @@ defmodule Volt.Watcher do
     end
   end
 
+  defp tailwind_source?(path, state) do
+    state.config[:tailwind] &&
+      Enum.any?(state.config.tailwind_sources, fn source ->
+        not Map.get(source, :negated, false) and
+          GlobEx.match?(
+            GlobEx.compile!(Path.join(Path.expand(source.base), source.pattern)),
+            path
+          )
+      end)
+  end
+
   defp reload_path?(path, state) do
     Enum.any?(state.reload_dirs, &Volt.Path.inside?(path, &1))
   end
@@ -437,10 +799,18 @@ defmodule Volt.Watcher do
 
   @impl true
   def terminate(_reason, state) do
-    Enum.each(state.fs_pids, &GenServer.stop/1)
+    Enum.each(state.fs_pids, fn pid ->
+      if Process.alive?(pid), do: GenServer.stop(pid)
+    end)
+
+    if state.config[:tailwind] && is_nil(state.config[:tailwind_worker]),
+      do: Volt.Tailwind.Supervisor.release(state.config.tailwind_key)
+
+    if state.session != :default, do: Volt.Dev.Cleanup.run(state.session)
+    if state.managed_key, do: Registry.unregister(Volt.Dev.WatcherRegistry, state.managed_key)
     :ok
   end
 
   defp maybe_expand(nil), do: nil
-  defp maybe_expand(path), do: Path.expand(path)
+  defp maybe_expand(path), do: Paths.expand(path)
 end
diff --git a/lib/volt/watcher/ignore.ex b/lib/volt/watcher/ignore.ex
new file mode 100644
index 0000000..5a5bebc
--- /dev/null
+++ b/lib/volt/watcher/ignore.ex
@@ -0,0 +1,39 @@
+defmodule Volt.Watcher.Ignore do
+  @moduledoc false
+
+  @default_patterns [
+    "**/.git/**",
+    "**/node_modules/**",
+    "**/test-results/**",
+    "**/_build/**",
+    "**/deps/**"
+  ]
+
+  @spec compile([String.t()], [String.t()]) :: [GlobEx.t()]
+  def compile(patterns, roots),
+    do: compile_patterns(@default_patterns, roots) ++ compile_explicit(patterns, roots)
+
+  # Configured patterns also resolve from the project directory, so that
+  # `_build/**` matches a watch root that itself lives inside `_build`.
+  def compile_explicit(patterns, roots),
+    do: compile_patterns(patterns, Enum.uniq([Volt.Paths.root() | roots]))
+
+  defp compile_patterns(patterns, roots) do
+    patterns
+    |> Enum.uniq()
+    |> Enum.flat_map(&compile_pattern(&1, roots))
+  end
+
+  defp compile_pattern(pattern, roots) do
+    case Path.type(pattern) do
+      :relative -> Enum.map(roots, &compile_relative(pattern, &1))
+      _absolute -> [GlobEx.compile!(pattern, match_dot: true)]
+    end
+  end
+
+  defp compile_relative(pattern, root) do
+    root
+    |> Path.join(pattern)
+    |> GlobEx.compile!(match_dot: true)
+  end
+end
diff --git a/lib/volt/watcher/path.ex b/lib/volt/watcher/path.ex
new file mode 100644
index 0000000..b95cd14
--- /dev/null
+++ b/lib/volt/watcher/path.ex
@@ -0,0 +1,59 @@
+defmodule Volt.Watcher.Path do
+  @moduledoc false
+
+  @spec normalize_from_roots(String.t(), [String.t()]) :: String.t()
+  def normalize_from_roots(path, roots) do
+    path = Path.expand(path)
+
+    Enum.find_value(roots, path, fn root ->
+      root = Path.expand(root)
+
+      if Volt.Path.inside?(path, root) do
+        path
+      else
+        normalize_from_physical_root(path, root)
+      end
+    end)
+  end
+
+  defp normalize_from_physical_root(path, root) do
+    with {:ok, root_stat} <- File.stat(root),
+         {:ok, relative} <- relative_to_physical_root(path, root_stat, []) do
+      Path.expand(relative, root)
+    else
+      _not_found -> nil
+    end
+  end
+
+  defp relative_to_physical_root(path, root_stat, parts) do
+    case File.stat(path) do
+      {:ok, path_stat} ->
+        if same_file?(path_stat, root_stat) do
+          {:ok, join_parts(parts)}
+        else
+          continue_to_parent(path, root_stat, parts)
+        end
+
+      _error ->
+        continue_to_parent(path, root_stat, parts)
+    end
+  end
+
+  defp continue_to_parent(path, root_stat, parts) do
+    parent = Path.dirname(path)
+
+    if parent == path do
+      :error
+    else
+      relative_to_physical_root(parent, root_stat, [Path.basename(path) | parts])
+    end
+  end
+
+  defp join_parts([]), do: "."
+  defp join_parts(parts), do: Path.join(parts)
+
+  defp same_file?(left, right) do
+    left.major_device == right.major_device and left.minor_device == right.minor_device and
+      left.inode == right.inode
+  end
+end
diff --git a/mix.exs b/mix.exs
index befa262..6ef2c18 100644
--- a/mix.exs
+++ b/mix.exs
@@ -1,18 +1,18 @@
 defmodule Volt.MixProject do
   use Mix.Project
 
-  @version "0.17.1"
+  @version "0.23.0"
   @source_url "https://github.com/elixir-volt/volt"
 
   def project do
     [
       app: :volt,
       version: @version,
-      elixir: "~> 1.17",
+      elixir: "~> 1.18",
       start_permanent: Mix.env() == :prod,
       deps: deps(),
       aliases: aliases(),
-      test_ignore_filters: [&String.starts_with?(&1, "test/support/")],
+      elixirc_paths: elixirc_paths(Mix.env()),
       dialyzer: [plt_add_apps: [:mix, :ex_unit], flags: [:no_opaque]],
       name: "Volt",
       description:
@@ -31,14 +31,17 @@ defmodule Volt.MixProject do
     ]
   end
 
+  defp elixirc_paths(:test), do: ["lib", "test/support"]
+  defp elixirc_paths(_env), do: ["lib"]
+
   defp deps do
     [
       {:reach, "~> 2.6.1", only: [:dev, :test], runtime: false},
-      {:glob_ex, "~> 0.1"},
-      {:oxc, "~> 0.17.2"},
-      {:vize, "~> 0.14.0"},
-      {:oxide_ex, "~> 0.2.1"},
-      {:quickbeam, "~> 0.10.20"},
+      {:glob_ex, "~> 0.1.12"},
+      {:oxc, "~> 0.19.0"},
+      {:vize, "~> 0.17.1"},
+      {:oxide_ex, "~> 0.2.2"},
+      {:quickbeam, "~> 0.11.3"},
       {:dotenvy, "~> 1.1"},
       {:floki, "~> 0.38"},
       {:plug, "~> 1.16"},
@@ -46,16 +49,18 @@ defmodule Volt.MixProject do
       {:websock_adapter, "~> 0.5"},
       {:file_system, "~> 1.0"},
       {:jason, "~> 1.4"},
-      {:json_codec, "~> 0.2.3"},
-      {:igniter, "~> 0.5", optional: true},
-      {:npm, "~> 0.7.5"},
+      {:json_codec, "~> 0.3"},
+      {:lumis, "~> 0.10", optional: true},
+      {:lumis_wasm_typescript, "~> 0.26", only: :test},
+      {:igniter, ">= 0.8.4 and < 1.0.0", optional: true},
+      {:npm, "~> 0.7.6"},
       {:dialyxir, "~> 1.4", only: [:dev, :test], runtime: false},
       {:credo, "~> 1.7", only: [:dev, :test], runtime: false},
       {:ex_slop, "~> 0.4", only: [:dev, :test], runtime: false},
       {:ex_dna, "~> 1.1", only: [:dev, :test], runtime: false},
       {:ex_doc, "~> 0.35", only: :dev, runtime: false},
       {:makeup_js, "~> 0.1", only: :dev, runtime: false},
-      {:bandit, "~> 1.0", only: :test},
+      {:bandit, ">= 1.12.5 and < 2.0.0", only: :test},
       {:playwright_ex, "~> 0.5", only: :test}
     ]
   end
@@ -63,6 +68,10 @@ defmodule Volt.MixProject do
   defp aliases do
     [
       lint: [
+        # `mix format` loads Volt.Formatter from the existing build and only
+        # compiles when the module is missing, so a cached build would format
+        # with stale plugin code.
+        "compile",
         "format --check-formatted",
         "volt.js.check --type-aware --type-check",
         "credo --strict",
@@ -70,7 +79,9 @@ defmodule Volt.MixProject do
         "reach.check --arch --dead-code --smells --strict",
         "dialyzer"
       ],
-      setup: ["deps.get"],
+      setup: ["deps.get", "volt.priv.vendor priv/ts"],
+      "hex.build": ["cmd mix volt.priv.vendor priv/ts", "hex.build"],
+      "hex.publish": ["cmd mix volt.priv.vendor priv/ts", "hex.publish"],
       ci: ["lint", "cmd env MIX_ENV=test mix test"]
     ]
   end
@@ -136,6 +147,7 @@ defmodule Volt.MixProject do
           Volt.Env,
           Volt.JS.Runtime,
           Volt.JS.Format,
+          Volt.NPM,
           Volt.Priv
         ],
         Formatting: [Volt.Formatter, Volt.Format],
@@ -217,7 +229,8 @@ defmodule Volt.MixProject do
           Volt.JS.Asset,
           Volt.JS.AST,
           Volt.JS.Extensions,
-          Volt.JS.Helpers,
+          Volt.JS.Discovery,
+          Volt.JS.Lint.Config,
           Volt.JS.ImportExtractor,
           Volt.JS.ImportExtractor.Result,
           Volt.JS.Package,
diff --git a/mix.lock b/mix.lock
index 981dda2..fb88ccb 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,7 +1,7 @@
 %{
-  "bandit": {:hex, :bandit, "1.12.0", "6c5214daa2469644ac4ab0113b98abc24f75e348378e6a974c6343b3e5da22ef", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.5", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "45dac82dc86f45cf4a196dee9cc5a8b791d9c9469d996055f055e6ee36c66e20"},
+  "bandit": {:hex, :bandit, "1.12.5", "af205a8e550f304caae09a97d29fd3c79a7f337526ea7cd772d2ff11d2f7c800", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.5", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "c5684ca062fa407cac115aec3256383f3e2ec9fdced7904d59cf5a7bb7ed6181"},
   "bunt": {:hex, :bunt, "1.0.0", "081c2c665f086849e6d57900292b3a161727ab40431219529f13c4ddcf3e7a44", [:mix], [], "hexpm", "dc5f86aa08a5f6fa6b8096f0735c4e76d54ae5c9fa2c143e5a1fc7c1cd9bb6b5"},
-  "castore": {:hex, :castore, "1.0.19", "6903cabdfd9d1af46454126e7c8385186659dd33ecfb74a885cae52221ad6109", [:mix], [], "hexpm", "3669e6cab13f54c2df26b3e6833745d647f35b6e30d8ddd5975df0d5c842ca98"},
+  "castore": {:hex, :castore, "1.0.21", "0a0e8330dc267a40a3b7ad86d39302764bb71758172904e6a59d5ad6443ce307", [:mix], [], "hexpm", "e42e22723e25dbd46876d056a03f685513d6e98f6b5e555dc551321decd76c5c"},
   "credo": {:hex, :credo, "1.7.19", "cc52129665fc7c15143d47838fda0f9cd6dac9ceced7bf4da6f85fcbfe64b12a", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "2d8bc95d5a7bb99dd2613621d4f08c6a3575c3fd4b62e6a2b48a100352a557b8"},
   "db_connection": {:hex, :db_connection, "2.10.1", "d5465f6bcc125c1b8981c1dbf23c193ca16f446ec0b25832dc174f74f18be510", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "18ed94c6e627b4bf452dbd4df61b69a35a1e768525140bc1917b7a685026a6a3"},
   "decimal": {:hex, :decimal, "3.1.1", "430d87b04011ce6cbd4fd205be758311a81f87d552d40904abd00f015935b1d0", [:mix], [], "hexpm", "c5f25f2ced74a0587d03e6023f595db8e924c9d3922c8c8ffd9edfc4498cf1f6"},
@@ -12,60 +12,63 @@
   "ecto_sql": {:hex, :ecto_sql, "3.14.0", "06446ab8410d2f85bfbb80857ee224ab3b693700cbb38f6535d507449a627b2e", [:mix], [{:db_connection, "~> 2.9", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 3.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:ecto, "~> 3.14.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:myxql, "~> 0.8", [hex: :myxql, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.19 or ~> 1.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:tds, "~> 2.1.1 or ~> 2.2", [hex: :tds, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4.0 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "f4d8d36faf294c9417b5a37ec7ac8217ee2abdef5fcf197ba690f361548d3949"},
   "elixir_make": {:hex, :elixir_make, "0.10.0", "16577e2583a79bb79237bbff349619ef5d80afffc07eac6e4faf0d00e2ddaf7d", [:mix], [], "hexpm", "dc1f09fb7fa68866b886abd5f0f3c83553b1a19a52359a899e92af1bb3b31982"},
   "erlex": {:hex, :erlex, "0.2.9", "7debbbaa9f4f368b8cd648983e0f1d7963028508e9c59e9d4ed504e94ef52a55", [:mix], [], "hexpm", "8cfffc0ec7159e6d73de2ab28a588064de80f88b2798d5cbe4482cbbc200178b"},
-  "ex_ast": {:hex, :ex_ast, "0.12.0", "052ad63711da41b7efbfb3490dbf3d757bb67caec17d02f6deb0db4a0363e5f6", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:sourceror, "~> 1.7", [hex: :sourceror, repo: "hexpm", optional: false]}], "hexpm", "66b4797f157d32f0a63c6da227515f78816c0ac8f621f6d7a2b22108e7b4dd85"},
+  "ex_ast": {:hex, :ex_ast, "0.12.10", "1126eb2afe3218e7a8a53ce85adf1056c528c88fbb5adcbe0191b647b842b377", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:sourceror, "~> 1.7", [hex: :sourceror, repo: "hexpm", optional: false]}], "hexpm", "e03f668c4354e3a1382c3d762c0fcc82ca9670f6f37e62b9097ce752be6adf39"},
   "ex_dna": {:hex, :ex_dna, "1.5.3", "c4c4736c1e22538002844f194fbd2b942f3a0c2a3517c843306b219f27bc5525", [:mix], [{:credo, "~> 1.7", [hex: :credo, repo: "hexpm", optional: true]}, {:gen_lsp, "~> 0.11", [hex: :gen_lsp, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: true]}], "hexpm", "28196153994e99aae29a955ee9f1d37ea6d3a33dbac0896ac4b937ebc622c313"},
   "ex_doc": {:hex, :ex_doc, "0.40.3", "4a972ffe64bc07dc605af487e98fc19b72a4185f55ca031b94c0552d6071c1d9", [:mix], [{:earmark_parser, "~> 1.4.44", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "2756e357742fecd9749b489b85d67c9ce99c465f2e75728d9e6dc8d704b973de"},
   "ex_slop": {:hex, :ex_slop, "0.4.2", "142aba9a82eddfb258e39c45d59392ab3cdb6b5a3ad401b09b362b7134fc54eb", [:mix], [{:credo, "~> 1.7", [hex: :credo, repo: "hexpm", optional: false]}], "hexpm", "c7f5316f755f83566e7a0a049f6fedfcd5ff916fce83c6ebfdf806be62fd7a69"},
   "file_system": {:hex, :file_system, "1.1.1", "31864f4685b0148f25bd3fbef2b1228457c0c89024ad67f7a81a3ffbc0bbad3a", [:mix], [], "hexpm", "7a15ff97dfe526aeefb090a7a9d3d03aa907e100e262a0f8f7746b78f8f87a5d"},
-  "finch": {:hex, :finch, "0.23.0", "e3f9287ac25a8832f848b144c2b57346aac65b205e2e0629a52adfe6507fd837", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "80e58d3f936f57e3fdf404f83a3642897ae6d9fb642934e46da4d8fe761b99d5"},
+  "finch": {:hex, :finch, "0.24.0", "4022b6194e907b6d9b597c168001cac38e488a35fe36cef9d8297e3159782510", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "33ba40069c3587c2f99f9125b766e19dad87d6d54be3c6961db2304df04cef00"},
   "floki": {:hex, :floki, "0.38.4", "10f98971e892aed2c2f1b3a0f928e488e3797e1c6dd3dfd98db40b14e9a78bcf", [:mix], [], "hexpm", "bdb34645eee8e79845c7edaca2d4099a52804ee4d4a3ecc683a69451f0244973"},
-  "glob_ex": {:hex, :glob_ex, "0.1.11", "cb50d3f1ef53f6ca04d6252c7fde09fd7a1cf63387714fe96f340a1349e62c93", [:mix], [], "hexpm", "342729363056e3145e61766b416769984c329e4378f1d558b63e341020525de4"},
-  "hex_solver": {:hex, :hex_solver, "0.2.3", "0d2ee20fbceb251d573f03ef34852e325529c2874ab66d1b576384021318996c", [:mix], [], "hexpm", "9daeae2ea6b8ad3dc7f51a10484f6bc1d0f705c31063383830a7167ab93b887b"},
-  "hpax": {:hex, :hpax, "1.0.4", "777de5d433b0fbdc7c418159c8055910faa8047ffdb3d6b31098d2a46cd7685c", [:mix], [], "hexpm", "afc7cb142ebcc2d01ce7816190b98ce5dd49e799111b24249f3443d730f377ca"},
-  "igniter": {:hex, :igniter, "0.8.1", "3c6ea47f3a6031015e29da8b4ba5c685f0a2e409facf63041fd83e982ca3aa89", [:mix], [{:ex_ast, "~> 0.5", [hex: :ex_ast, repo: "hexpm", optional: false]}, {:glob_ex, "~> 0.1.7", [hex: :glob_ex, repo: "hexpm", optional: false]}, {:jason, "~> 1.4.5", [hex: :jason, repo: "hexpm", optional: false]}, {:owl, "~> 0.11", [hex: :owl, repo: "hexpm", optional: false]}, {:phx_new, "~> 1.7", [hex: :phx_new, repo: "hexpm", optional: true]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}, {:rewrite, ">= 1.1.1 and < 2.0.0-0", [hex: :rewrite, repo: "hexpm", optional: false]}, {:sourceror, "~> 1.4", [hex: :sourceror, repo: "hexpm", optional: false]}, {:spitfire, ">= 0.1.3 and < 1.0.0-0", [hex: :spitfire, repo: "hexpm", optional: false]}], "hexpm", "d99472e6daf3bfc3675d699c6c7ace9196f377207aab83e09d7b95e9d90e8ae8"},
+  "glob_ex": {:hex, :glob_ex, "0.1.12", "7b2d9369c20e2697efcfd185d13d6e84c94cd3bfd2730fbde613141c2e015c00", [:mix], [], "hexpm", "2e2fac83f113514434c7eaf267b4c38af2f91766f1cab2c5db7053b7fc1ee0bb"},
+  "hex_solver": {:hex, :hex_solver, "0.3.0", "81e7659ad6caba1f856d89fc7ca52f88e8eb4f801deedcdce215f9006d706d1d", [:mix], [], "hexpm", "8a04c8ef0df25ca1f5e4d7d5f32833fac569f5c6442f05e216ee33615593e64d"},
+  "hpax": {:hex, :hpax, "1.1.0", "782931867cc23217c68fb5f68fe1a11f5e7544c7fda82c8a7019a5df5a4a1cdf", [:mix], [], "hexpm", "0b8d0f05832f55571d65ac720f79bf8994138ffbb133209dc4685eae0ad456a8"},
+  "igniter": {:hex, :igniter, "0.8.4", "f79f1bbdc2fb7b9ca030a22d12a585b060cbf5b94b9d3f23b1148578a9e05d11", [:mix], [{:ex_ast, "~> 0.5", [hex: :ex_ast, repo: "hexpm", optional: false]}, {:glob_ex, "~> 0.1.7", [hex: :glob_ex, repo: "hexpm", optional: false]}, {:jason, "~> 1.4.5", [hex: :jason, repo: "hexpm", optional: false]}, {:owl, "~> 0.11", [hex: :owl, repo: "hexpm", optional: false]}, {:phx_new, "~> 1.7", [hex: :phx_new, repo: "hexpm", optional: true]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}, {:rewrite, ">= 1.1.1 and < 2.0.0-0", [hex: :rewrite, repo: "hexpm", optional: false]}, {:sourceror, "~> 1.4", [hex: :sourceror, repo: "hexpm", optional: false]}, {:spitfire, ">= 0.1.3 and < 1.0.0-0", [hex: :spitfire, repo: "hexpm", optional: false]}], "hexpm", "a9b1cbec996ccb100b4f7d8130129b2dd3f18eb4224ac9a0e907e428ca90dbd7"},
   "jason": {:hex, :jason, "1.4.5", "2e3a008590b0b8d7388c20293e9dcc9cf3e5d642fd2a114e4cbbb52e595d940a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b0c823996102bcd0239b3c2444eb00409b72f6a140c1950bc8b457d836b30684"},
-  "json_codec": {:hex, :json_codec, "0.2.3", "b75b2f76a2c89844a72f2dcc8f83c045d0fb030da041b9c2278c82f70067ec78", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "4dad674cbee1119161b555a155ef1537908ee337d49e619e1b155313ec523b71"},
+  "json_codec": {:hex, :json_codec, "0.3.1", "81f738e212308c85344e11da00af6d8b52bd486224ee24c1f51b95df0604aeae", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: true]}, {:json_spec, "~> 1.2", [hex: :json_spec, repo: "hexpm", optional: false]}], "hexpm", "dffea3198d3f1fe9a39aa176ab0d6988b8c80dd85a67e913b323d4ec7c57ca9d"},
+  "json_spec": {:hex, :json_spec, "1.2.0", "c67f73cdc4166e955b2f1095d3f44dd78c197337038f1a5301fb526b6c87ab04", [:mix], [], "hexpm", "3639961babad7d6bc45f3a2d96a49c18ec70614761bb84ce58b64e9fad9354de"},
   "libgraph": {:hex, :libgraph, "0.16.0", "3936f3eca6ef826e08880230f806bfea13193e49bf153f93edcf0239d4fd1d07", [:mix], [], "hexpm", "41ca92240e8a4138c30a7e06466acc709b0cbb795c643e9e17174a178982d6bf"},
+  "lumis": {:hex, :lumis, "0.10.0", "4b0b773447f7dace8be7b0c93abe4d24e9b7c81034ac2757003f3ac4b7ac3450", [:mix], [{:nimble_options, "~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:rustler, "~> 0.29", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "5e3845defa32871a404d6a51ad2d8d3c423077f6f80149e632511f26460f27dc"},
+  "lumis_wasm_typescript": {:hex, :lumis_wasm_typescript, "0.26.2", "6f6972ba900860bfa5b601333a216faa24a9e1f59dac84b2beae3911941b006b", [:mix], [], "hexpm", "277acc22eb48133299e137ba5f127bf635409192dd5f5c6f5839e52fd7c0bc72"},
   "makeup": {:hex, :makeup, "1.2.1", "e90ac1c65589ef354378def3ba19d401e739ee7ee06fb47f94c687016e3713d1", [:mix], [{:nimble_parsec, "~> 1.4", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "d36484867b0bae0fea568d10131197a4c2e47056a6fbe84922bf6ba71c8d17ce"},
   "makeup_elixir": {:hex, :makeup_elixir, "1.0.1", "e928a4f984e795e41e3abd27bfc09f51db16ab8ba1aebdba2b3a575437efafc2", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "7284900d412a3e5cfd97fdaed4f5ed389b8f2b4cb49efc0eb3bd10e2febf9507"},
   "makeup_erlang": {:hex, :makeup_erlang, "1.1.0", "835f7e60792e08824cda445639555d7bf1bbbddb1b60b306e33cb6f6db24dc74", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "1cd6780fb1dd1a03979abaed0fe82712b0625118fd5257d3ebbf73f960c73c3c"},
   "makeup_js": {:hex, :makeup_js, "0.1.0", "ffa8ce9db95d14dcd09045334539d5992d540d63598c592d4805b7674bdd6675", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "3f0c1a5eb52c9737b1679c926574e83bb260ccdedf08b58ee96cca7c685dea75"},
   "mime": {:hex, :mime, "2.0.7", "b8d739037be7cd402aee1ba0306edfdef982687ee7e9859bee6198c1e7e2f128", [:mix], [], "hexpm", "6171188e399ee16023ffc5b76ce445eb6d9672e2e241d2df6050f3c771e80ccd"},
-  "mint": {:hex, :mint, "1.9.1", "3bc120b743ed2e99ad920910f2613e9faebabb2257731b0e2ea4d8ccd9eceede", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "831101bd560b086316fab5f7adb21a4f3455717d8e4bc8368b052e09aa9163e0"},
-  "mint_web_socket": {:hex, :mint_web_socket, "1.0.5", "60354efeb49b1eccf95dfb75f55b08d692e211970fe735a5eb3188b328be2a90", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "04b35663448fc758f3356cce4d6ac067ca418bbafe6972a3805df984b5f12e61"},
+  "mint": {:hex, :mint, "1.11.0", "a713551624815c0435237b93d90ea8b9b14254690c66f732d0ef8930f76ff1d9", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 1.1", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "c6279ba2d6aa3a383a1d4cfbe7b59f42e6efd400f58d8e2acfeac48a438693ab"},
+  "mint_web_socket": {:hex, :mint_web_socket, "1.0.6", "5ffcf350df5b90f2d7a04adf877165228804993714592512374218d4679e325a", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "0c360e9012413f1c115a63532601eb5d63731aab7010949178769760686c1698"},
   "muontrap": {:hex, :muontrap, "1.8.0", "3c5dab5bc91d5a16d14cd85b130ae7d35a9c469564a11ba4b2ebbcd7ccf5bc05", [:make, :mix], [{:elixir_make, "~> 0.6", [hex: :elixir_make, repo: "hexpm", optional: false]}], "hexpm", "45ff36451303cbdefe1c66da3681b5aff078ee5737348f554f0017daa66284af"},
   "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.2", "8efba0122db06df95bfaa78f791344a89352ba04baedd3849593bfce4d0dc1c6", [:mix], [], "hexpm", "4b21398942dda052b403bbe1da991ccd03a053668d147d53fb8c4e0efe09c973"},
   "nimble_pool": {:hex, :nimble_pool, "1.1.0", "bf9c29fbdcba3564a8b800d1eeb5a3c58f36e1e11d7b7fb2e084a643f645f06b", [:mix], [], "hexpm", "af2e4e6b34197db81f7aad230c1118eac993acc0dae6bc83bac0126d4ae0813a"},
-  "npm": {:hex, :npm, "0.7.5", "d8680384b4116a29270cd1fb706da017d1be3870d7d2993de382140d7b98d378", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "174f6b230669f08240a87bef76f3d9ed03e03c126fea6ea4d1a3011a1681a95f"},
+  "npm": {:hex, :npm, "0.7.6", "de8ca3dd26a40fac7ab8a17680088b8d55bab0e0294be9770b029c276361482f", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:npm_semver, "~> 0.1.0", [hex: :npm_semver, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}], "hexpm", "e0a1ce77e3e49ec108e095aba133bd315e86da298dba26b142a105972141d9ef"},
   "npm_semver": {:hex, :npm_semver, "0.1.0", "3ab2c2a151d8c87c364209b2ca1a4fd2ab98507ed61afbd1ea12c1826e67200a", [:mix], [{:hex_solver, "~> 0.2", [hex: :hex_solver, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "77afbc4c523c19a572325190bc4c968ec027e1c6ef8538bcddacf835966072fa"},
   "owl": {:hex, :owl, "0.13.1", "1ec4a5dea170465f0e90c502c203079224516bc0cbd599281c8667b3c6ef8848", [:mix], [{:ucwidth, "~> 0.2", [hex: :ucwidth, repo: "hexpm", optional: true]}], "hexpm", "351e768af8f2edc575cdaab1a5a2f6d6381be591758a026c701c703145508a0c"},
-  "oxc": {:hex, :oxc, "0.17.2", "c668faab70561710ff9c183636ceb9856e450aa70c531d55c10b24fbca0f9eac", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "e73e315562f2d495c012dbf64067ef784db4b5bb8bb20dec31b2ab71fd40bd8c"},
-  "oxide_ex": {:hex, :oxide_ex, "0.2.1", "ff0e1c03f58c151ca87e3b11847801a751853894fd926910f459ef5918cc655a", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "25bebc0d30362dead560e815a1380c266d018924a71a548ea2b1582f8dcd77bb"},
+  "oxc": {:hex, :oxc, "0.19.0", "9786fc88ec3da84da1fec5e08bb94b108e3917288cdac07d62842edfcd2500ac", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:json_codec, "~> 0.3", [hex: :json_codec, repo: "hexpm", optional: false]}, {:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "ffeec25c488d87144fc12e14d30bca92997576303be2458e80e6e84dd756a296"},
+  "oxide_ex": {:hex, :oxide_ex, "0.2.2", "063e0d2899e81632b7efc7849eb1dd89a7a623290a075c446b43bef14cf5795e", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "577a2fbd97c46904a31143bb700cdb374105085cfd1f7605416bb6c012cb7f60"},
   "pegasus": {:hex, :pegasus, "0.2.6", "b4af6522326fbb2ffd1bb706e78ec05854fbcb4b03a7fe08f8db2e9de1d0be67", [:mix], [{:nimble_parsec, "~> 1.2", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "0ac159f0ccab7967cf90208327cc8a35788874814c8d78e19d47104d3fc049b9"},
   "pi_bridge": {:hex, :pi_bridge, "0.6.21", "f1a63da5f49fef4f6b35e98edd5400cbd64a49fb8bda84be41b7e91f3deb0b89", [:mix], [{:bandit, "~> 1.8", [hex: :bandit, repo: "hexpm", optional: false]}, {:dune, "~> 0.3", [hex: :dune, repo: "hexpm", optional: true]}, {:ecto_sql, "~> 3.13", [hex: :ecto_sql, repo: "hexpm", optional: false]}, {:ex_ast, "~> 0.12", [hex: :ex_ast, repo: "hexpm", optional: false]}, {:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:json_codec, "~> 0.1.3", [hex: :json_codec, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:quackdb, "~> 0.5.4", [hex: :quackdb, repo: "hexpm", optional: false]}, {:reach, "~> 2.6", [hex: :reach, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}, {:req_llm, "~> 1.6", [hex: :req_llm, repo: "hexpm", optional: true]}], "hexpm", "b226fb60965a8e928186af3c3b96fe8f0fefd8c6cc7be679d6e169ba84105de9"},
   "playwright_ex": {:hex, :playwright_ex, "0.7.1", "4a8a3f317734a5d20c4f25b5b425d565d05730166013f86f0c1a799714e61e2d", [:mix], [{:nimble_options, "~> 1.1", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:websockex, "~> 0.4", [hex: :websockex, repo: "hexpm", optional: true]}], "hexpm", "558176309cf322b8ba5c4f85ec6c655c1667cd68531db83d1d3065bd572755c2"},
   "plug": {:hex, :plug, "1.20.3", "56c480c633ec2ce10140e236e15233bf576e1d323887d7c96711bd02ab5160db", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "be266aee1b8536ef6409d58cf39a3121319f0ec47cfa1b24024485aa0e76ad76"},
-  "plug_crypto": {:hex, :plug_crypto, "2.1.1", "19bda8184399cb24afa10be734f84a16ea0a2bc65054e23a62bb10f06bc89491", [:mix], [], "hexpm", "6470bce6ffe41c8bd497612ffde1a7e4af67f36a15eea5f921af71cf3e11247c"},
+  "plug_crypto": {:hex, :plug_crypto, "2.2.0", "144014737daaf485407f5ed77daeaad74d651b216a28c87543f8cc7043f8efc8", [:mix], [], "hexpm", "83a95744ab1c75876542b6fab135fcc176280e0f301a111c1f757fddcec95d2c"},
   "protoss": {:hex, :protoss, "1.1.0", "853533313989751c7da5b0e1ce71501a23f3dc41f128709478af40daccc6e959", [:mix], [], "hexpm", "c2f874383dd047fcfdf467b814dd33a208a4d24a467aef90d86185b41a0752ad"},
   "quackdb": {:hex, :quackdb, "0.5.13", "854294a5a85e0f2972d2229da8dfb25afd2cda500e80e477f6987bff823c2b21", [:mix], [{:castore, "~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:db_connection, "~> 2.7", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:ecto_sql, "~> 3.13", [hex: :ecto_sql, repo: "hexpm", optional: true]}, {:explorer, "~> 0.11", [hex: :explorer, repo: "hexpm", optional: true]}, {:fsst, "~> 0.1.2", [hex: :fsst, repo: "hexpm", optional: true]}, {:geo, "~> 4.1", [hex: :geo, repo: "hexpm", optional: true]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:muontrap, "~> 1.5", [hex: :muontrap, repo: "hexpm", optional: false]}, {:table, "~> 0.1", [hex: :table, repo: "hexpm", optional: true]}, {:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:varint, "~> 1.6", [hex: :varint, repo: "hexpm", optional: false]}], "hexpm", "a5d18e54de682bde9f4ab1866126aa90c26223866bc693bf56cdf9dafa3859d3"},
-  "quickbeam": {:hex, :quickbeam, "0.10.20", "286874038d8c409ca9eb9eb63fd074fb44a474e8f68ddb53f7b6cf42611a4036", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.5", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.17.2", [hex: :oxc, repo: "hexpm", optional: false]}, {:zigler, "~> 0.15.2", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.4", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "211bf1f22de6dc4def9ae07af529904ff49f701740508331b7e7673220640663"},
+  "quickbeam": {:hex, :quickbeam, "0.11.3", "a670f982f2a7e074bbd06289e2bd3be8291246967d3fa7d8822c72c2510db329", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:json_codec, "~> 0.3", [hex: :json_codec, repo: "hexpm", optional: true]}, {:mint, "~> 1.10", [hex: :mint, repo: "hexpm", optional: false]}, {:mint_web_socket, "~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:npm, "~> 0.7.6", [hex: :npm, repo: "hexpm", optional: true]}, {:oxc, "~> 0.17.8 or ~> 0.18.0 or ~> 0.19.0", [hex: :oxc, repo: "hexpm", optional: false]}, {:varint, "~> 1.6", [hex: :varint, repo: "hexpm", optional: false]}, {:zigler, "~> 0.16.0", [hex: :zigler, repo: "hexpm", optional: true]}, {:zigler_precompiled, "~> 0.1.6", [hex: :zigler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "ee35486b0987e535d05b5f846786d0d4aadde34bffc46d83ecc69b419adc070f"},
   "reach": {:hex, :reach, "2.6.1", "33f749a1e15baa843aedd3e3e9a282322eef1e6c59d9b8a5072c8427359f9658", [:mix], [{:boxart, "~> 0.3.3", [hex: :boxart, repo: "hexpm", optional: true]}, {:ex_ast, "~> 0.12.0", [hex: :ex_ast, repo: "hexpm", optional: false]}, {:ex_dna, "~> 1.5", [hex: :ex_dna, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:libgraph, "~> 0.16.0", [hex: :libgraph, repo: "hexpm", optional: false]}, {:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: true]}, {:makeup_js, "~> 0.1", [hex: :makeup_js, repo: "hexpm", optional: true]}, {:quickbeam, "~> 0.10", [hex: :quickbeam, repo: "hexpm", optional: true]}], "hexpm", "2d7e8a26a999be50cf716cf5786c5d1570d04b397ee047d430cab1d6956714cc"},
-  "req": {:hex, :req, "0.6.2", "b9b2024f35bcf60a92cc8cad2eaaf9d4e7aace463ff74be1afe5986830184413", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.21", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "cc9cd30a2ddd04989929b887178e1610c940456d962c6c3a52df6146d2eef9bf"},
+  "req": {:hex, :req, "0.7.5", "0c3293cbf7717aba20b1b1b3ea13fe8d3fdf6f1557490f390c3f1ef6dd9db955", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:finch, "~> 0.21", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "576853c4bf403faa3c1fa5d093e0759227083b78f8a6864c67d62c0a9c45514d"},
   "rewrite": {:hex, :rewrite, "1.3.0", "67448ba7975690b35ba7e7f35717efcce317dbd5963cb0577aa7325c1923121a", [:mix], [{:glob_ex, "~> 0.1", [hex: :glob_ex, repo: "hexpm", optional: false]}, {:sourceror, "~> 1.0", [hex: :sourceror, repo: "hexpm", optional: false]}, {:text_diff, "~> 0.1", [hex: :text_diff, repo: "hexpm", optional: false]}], "hexpm", "d111ac7ff3a58a802ef4f193bbd1831e00a9c57b33276e5068e8390a212714a5"},
   "rustler": {:hex, :rustler, "0.38.0", "7a8906998ff0d28e3021c0a73264abcda719bda344b2e58307c6805b0f87c9b4", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "704c03c1bf66be12b031c5a389347b91c81c5cb819a24b068b0de36fe4a5652a"},
-  "rustler_precompiled": {:hex, :rustler_precompiled, "0.9.0", "3a052eda09f3d2436364645cc1f13279cf95db310eb0c17b0d8f25484b233aa0", [:mix], [{:rustler, "~> 0.23", [hex: :rustler, repo: "hexpm", optional: true]}], "hexpm", "471d97315bd3bf7b64623418b3693eedd8e47de3d1cb79a0ac8f9da7d770d94c"},
+  "rustler_precompiled": {:hex, :rustler_precompiled, "0.10.0", "8f07ff0865cb09a6a0f75e11701e9a46e331e05f737da4e5b01374dcd25b68c0", [:mix], [{:rustler, "~> 0.28", [hex: :rustler, repo: "hexpm", optional: true]}], "hexpm", "c68c9dc732c12acfdf4a7fa06f4e6f48a641179e6be49a474c8a60809929c430"},
   "sourceror": {:hex, :sourceror, "1.12.2", "85bfd48159f020c0cbfc72f289f11456fdc05dc43719b6f2589fb969faefa113", [:mix], [], "hexpm", "da37d3da09c5b890528802c7056a8f585a061973820d7656b6e3649c14f0e9cb"},
-  "spitfire": {:hex, :spitfire, "0.3.13", "edd207b065eaec57acc5484097d0aa3e97fe4246168c54e67a9af040b8dee4c1", [:mix], [], "hexpm", "3601be88ceed4967b584e96444de3e1d12d6555ae0864a7390b9cd5332d134b4"},
+  "spitfire": {:hex, :spitfire, "0.4.1", "69e90335d00ca328295e1e1e77cac5d7575aa6d34274e3467ebfc654b8858be3", [:mix], [], "hexpm", "27d86f67681179682b15c6758d64ac2eb2b3637ed8340800c8b885c69754cdcd"},
   "telemetry": {:hex, :telemetry, "1.4.2", "a0cb522801dffb1c49fe6e30561badffc7b6d0e180db1300df759faa22062855", [:rebar3], [], "hexpm", "928f6495066506077862c0d1646609eed891a4326bee3126ba54b60af61febb1"},
   "text_diff": {:hex, :text_diff, "0.1.0", "1caf3175e11a53a9a139bc9339bd607c47b9e376b073d4571c031913317fecaa", [:mix], [], "hexpm", "d1ffaaecab338e49357b6daa82e435f877e0649041ace7755583a0ea3362dbd7"},
   "thousand_island": {:hex, :thousand_island, "1.5.0", "f50a213cac97262b6d5ebb85745aa2c00fec1413191e6e66834788d45425cecb", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "708923d40523e43cf99041ab37a0d4b0ec426ac6438fa3716ab23d919eaeb412"},
   "varint": {:hex, :varint, "1.6.0", "7bced828599b2eb84491a9f067f8a5a67fc35a946d3b7582278083c7fd434b00", [:mix], [], "hexpm", "2b4f4a20650aeebe993a70b03bb99571bcbddc27c361322c28b586d8a772ce4e"},
-  "vize": {:hex, :vize, "0.14.0", "af336da6947e9e7ac05f3f830550ab2314847e1101334577621cd3e1753f43ae", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "661e6209f74ae7b7c3cc06ca32833218022d5b46f29ee1a9c93e871502642a6e"},
+  "vize": {:hex, :vize, "0.17.1", "7fd4b00016ddc5c5dacd6734b15c3b0e82d30e39b14948072a53ededff6b1a98", [:mix], [{:rustler, "~> 0.36", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.8", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "94bfc91cf5c38d5901771c77c50bbc0e78e76abbfe663649fa0cd8a76e1dcbef"},
   "websock": {:hex, :websock, "0.5.3", "2f69a6ebe810328555b6fe5c831a851f485e303a7c8ce6c5f675abeb20ebdadc", [:mix], [], "hexpm", "6105453d7fac22c712ad66fab1d45abdf049868f253cf719b625151460b8b453"},
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diff --git a/package.json b/package.json
index 49eba5a..27a24b0 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,6 @@
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+    "postinstall": "node scripts/postinstall.mjs"
   }
 }
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new file mode 100644
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--- /dev/null
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new file mode 100644
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+  },
+  "policy": {
+    "allow_registry_redirects": false,
+    "allowed_registries": [
+      "https://registry.npmjs.org"
+    ],
+    "block_exotic_subdeps": true,
+    "exotic_deps": []
+  }
+}
diff --git a/priv/npm/tailwind.lock b/priv/npm/tailwind.lock
new file mode 100644
index 0000000..0f67f46
--- /dev/null
+++ b/priv/npm/tailwind.lock
@@ -0,0 +1,58 @@
+{
+  "lockfileVersion": 1,
+  "packages": {
+    "@tailwindcss/typography": {
+      "dependencies": {
+        "postcss-selector-parser": "6.0.10"
+      },
+      "has_install_script": false,
+      "integrity": "sha512-hwbzQuNUfcPvbegQFatVPl/MY/tcM9KLl963hQ5laJKPh81TEZ1+dNG9PirGvcaDBkp+BCshExAyKVPW91dozw==",
+      "optional_dependencies": {},
+      "tarball": "https://registry.npmjs.org/@tailwindcss/typography/-/typography-0.5.20.tgz",
+      "version": "0.5.20"
+    },
+    "cssesc": {
+      "dependencies": {},
+      "has_install_script": false,
+      "integrity": "sha512-/Tb/JcjK111nNScGob5MNtsntNM1aCNUDipB/TkwZFhyDrrE47SOx/18wF2bbjgc3ZzCSKW1T5nt5EbFoAz/Vg==",
+      "optional_dependencies": {},
+      "tarball": "https://registry.npmjs.org/cssesc/-/cssesc-3.0.0.tgz",
+      "version": "3.0.0"
+    },
+    "postcss-selector-parser": {
+      "dependencies": {
+        "cssesc": "^3.0.0",
+        "util-deprecate": "^1.0.2"
+      },
+      "has_install_script": false,
+      "integrity": "sha512-IQ7TZdoaqbT+LCpShg46jnZVlhWD2w6iQYAcYXfHARZ7X1t/UGhhceQDs5X0cGqKvYlHNOuv7Oa1xmb0oQuA3w==",
+      "optional_dependencies": {},
+      "tarball": "https://registry.npmjs.org/postcss-selector-parser/-/postcss-selector-parser-6.0.10.tgz",
+      "version": "6.0.10"
+    },
+    "tailwindcss": {
+      "dependencies": {},
+      "has_install_script": false,
+      "integrity": "sha512-gOhV3P7ufE62QDGg1zVaTgCR+EtPv92k2nIhVcVKcLmxT1sUBsQGhnZj175j+MqRt4zLF7ic+sCYjfhxMxj7YQ==",
+      "optional_dependencies": {},
+      "tarball": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.3.3.tgz",
+      "version": "4.3.3"
+    },
+    "util-deprecate": {
+      "dependencies": {},
+      "has_install_script": false,
+      "integrity": "sha512-EPD5q1uXyFxJpCrLnCc1nHnq3gOa6DZBocAIiI2TaSCA7VCJ1UJDMagCzIkXNsUYfD1daK//LTEQ8xiIbrHtcw==",
+      "optional_dependencies": {},
+      "tarball": "https://registry.npmjs.org/util-deprecate/-/util-deprecate-1.0.2.tgz",
+      "version": "1.0.2"
+    }
+  },
+  "policy": {
+    "allow_registry_redirects": false,
+    "allowed_registries": [
+      "https://registry.npmjs.org"
+    ],
+    "block_exotic_subdeps": true,
+    "exotic_deps": []
+  }
+}
diff --git a/priv/templates/volt.install/tsconfig.json.eex b/priv/templates/volt.install/tsconfig.json.eex
new file mode 100644
index 0000000..0aa0c0f
--- /dev/null
+++ b/priv/templates/volt.install/tsconfig.json.eex
@@ -0,0 +1,12 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "allowJs": true,
+    "noEmit": true,
+    "strict": true,
+    "lib": ["ES2022", "DOM", "DOM.Iterable"]
+  },
+  "include": ["assets/**/*", "deps/volt/priv/types/client/**/*.d.ts"]
+}
diff --git a/priv/ts/client/document.ts b/priv/ts/client/document.ts
new file mode 100644
index 0000000..97e009d
--- /dev/null
+++ b/priv/ts/client/document.ts
@@ -0,0 +1,224 @@
+import { Idiomorph } from 'idiomorph'
+import { pageReload } from './reload'
+
+const ETAG = 'data-volt-etag'
+const MORPH = 'data-volt-morph'
+
+export type OwnedChange = { index: number; attributes: Record<string, string> }
+
+export type AttributeChanges = { set: Record<string, string>; remove: string[] }
+export type HeadChanges = { remove: string[]; add: string[] }
+
+/** A page render pushed by the server, which already compared it with the previous one. */
+export type PushedDocument = {
+  html: string
+  etag: string
+  owned: OwnedChange[]
+  root: Record<string, AttributeChanges>
+  head: HeadChanges
+}
+
+/** Where this page is and which HTML it was served, for the server to keep track of it. */
+export function pageIdentity() {
+  const etag = document.querySelector(`script[${ETAG}]`)?.getAttribute(ETAG)
+  return etag ? { path: location.pathname + location.search, etag } : null
+}
+
+/**
+ * Apply a render the server pushed. The server compared it with the HTML it
+ * last rendered for this page, so it knows which owned elements it changed.
+ */
+export function applyDocument({ html, etag, owned, root, head }: PushedDocument) {
+  const preserve = document.querySelector(`script[${ETAG}]`)?.getAttribute(MORPH)
+  if (preserve === null || preserve === undefined) return pageReload()
+
+  const next = new DOMParser().parseFromString(html, 'text/html')
+  const changed = new Set(owned.map((change) => change.index))
+  if (!morphDocument(next, preserve, changed)) return pageReload()
+  if (!updateOwned(preserve, owned)) return pageReload()
+
+  updateRoot(root)
+  updateHead(head)
+  finishUpdate(etag)
+}
+
+// Only what the server changed is applied, so attributes that scripts set on
+// these elements, such as a theme, stay.
+function updateRoot(root: Record<string, AttributeChanges>) {
+  for (const [tag, { set, remove }] of Object.entries(root)) {
+    const element = tag === 'html' ? document.documentElement : document.body
+    for (const name of remove) element.removeAttribute(name)
+    for (const [name, value] of Object.entries(set)) element.setAttribute(name, value)
+  }
+}
+
+function updateHead({ remove, add }: HeadChanges) {
+  const live = [...document.head.children]
+
+  for (const html of remove) {
+    const gone = parseHeadElement(html)
+    const index = live.findIndex((element) => gone !== null && element.isEqualNode(gone))
+    if (index !== -1) live.splice(index, 1)[0]?.remove()
+  }
+
+  for (const html of add) {
+    const element = parseHeadElement(html)
+    if (element) document.head.append(element)
+  }
+}
+
+function parseHeadElement(html: string) {
+  return new DOMParser().parseFromString(`<head>${html}</head>`, 'text/html').head.firstElementChild
+}
+
+// The owner of an element re-renders it from its new attributes and says so by
+// cancelling the event. Without an owner listening, only a reload applies them.
+function updateOwned(preserve: string, owned: OwnedChange[]) {
+  if (owned.length === 0) return true
+  const elements = [...document.querySelectorAll(preserve)]
+
+  return owned.every(({ index, attributes }) => {
+    const element = elements[index]
+    if (!element) return false
+
+    for (const [name, value] of Object.entries(attributes)) element.setAttribute(name, value)
+
+    const event = new CustomEvent('volt:element-update', {
+      bubbles: true,
+      cancelable: true,
+      detail: { attributes }
+    })
+
+    return !element.dispatchEvent(event)
+  })
+}
+
+function finishUpdate(etag: string) {
+  document.querySelector(`script[${ETAG}]`)?.setAttribute(ETAG, etag)
+  document.dispatchEvent(new CustomEvent('volt:document-updated'))
+  console.log('[Volt] Document updated')
+}
+
+let revalidation: Promise<void> | undefined
+
+// The server-rendered HTML may have changed. A page that carries the entity tag
+// of its HTML asks the server, which answers 304 when it has not. Otherwise the
+// page is patched in place when it opted in and the change allows it, and
+// reloaded when not.
+export function revalidateDocument() {
+  revalidation ??= updateDocument().finally(() => {
+    revalidation = undefined
+  })
+
+  return revalidation
+}
+
+async function updateDocument() {
+  const client = document.querySelector(`script[${ETAG}]`)
+  const etag = client?.getAttribute(ETAG)
+  if (!client || !etag) return pageReload()
+
+  let response: Response
+
+  try {
+    response = await fetch(location.href, {
+      headers: { 'If-None-Match': etag, Accept: 'text/html' },
+      cache: 'no-store'
+    })
+  } catch {
+    return pageReload()
+  }
+
+  if (response.status === 304) return
+
+  const preserve = client.getAttribute(MORPH)
+  const nextEtag = response.headers.get('etag')
+  if (preserve === null || !response.ok || !nextEtag) return pageReload()
+
+  const next = new DOMParser().parseFromString(await response.text(), 'text/html')
+  if (!morphDocument(next, preserve)) return pageReload()
+
+  finishUpdate(nextEtag)
+}
+
+/**
+ * Patch the page to match `next`, the freshly rendered document.
+ *
+ * Returns false, changing nothing, when the difference cannot be applied by
+ * patching: scripts do not run again, stylesheets are not reloaded, and
+ * elements matching `preserve` are owned by client code such as a mounted
+ * component. `changed` holds the positions of owned elements the server changed.
+ */
+export function morphDocument(next: Document, preserve: string, changed = new Set<number>()) {
+  if (!sameItems(scripts(document), scripts(next))) return false
+  if (!sameItems(stylesheets(document), stylesheets(next))) return false
+
+  const preserved = preserve ? [...document.querySelectorAll(preserve)] : []
+  const nextPreserved = preserve ? [...next.querySelectorAll(preserve)] : []
+  if (!samePreserved(preserved, nextPreserved, changed)) return false
+
+  const owned = (node: Node) => preserve !== '' && node instanceof Element && node.matches(preserve)
+
+  document.title = next.title
+
+  // Morphing an element's children completes synchronously; the promise is for
+  // whole documents, whose head may load new assets.
+  void Idiomorph.morph(document.body, next.body, {
+    morphStyle: 'innerHTML',
+    callbacks: {
+      beforeNodeMorphed: (node) => !owned(node),
+      beforeNodeRemoved: (node) => !owned(node),
+      beforeNodeAdded: (node) => !owned(node)
+    }
+  })
+
+  return true
+}
+
+function sameItems(current: string[], next: string[]) {
+  return current.length === next.length && current.every((item, index) => item === next[index])
+}
+
+// Scripts the browser runs. Data blocks such as JSON are content and are patched.
+function scripts(doc: Document) {
+  return [...doc.querySelectorAll('script')]
+    .filter((script) => ['', 'module', 'text/javascript'].includes(script.type))
+    .map((script) => `${script.type}|${script.getAttribute('src') ?? ''}|${script.textContent}`)
+}
+
+function stylesheets(doc: Document) {
+  const links = [...doc.querySelectorAll<HTMLLinkElement>('link[rel="stylesheet"]')].map((link) =>
+    stylesheetUrl(link.getAttribute('href') ?? '')
+  )
+
+  // Volt adds and updates its own `<style data-volt-id>` elements.
+  const styles = [...doc.querySelectorAll('style:not([data-volt-id])')].map(
+    (style) => style.textContent ?? ''
+  )
+
+  return [...links, ...styles]
+}
+
+// A stylesheet update leaves a cache-busting `t` parameter on the link.
+function stylesheetUrl(href: string) {
+  const url = new URL(href, location.href)
+  url.searchParams.delete('t')
+  return url.toString()
+}
+
+// Client code may add attributes to an element it owns, such as a mount marker,
+// so only the attributes the server rendered are compared.
+// The elements in `changed` are ones the server knows it changed; their owners
+// are told separately.
+function samePreserved(current: Element[], next: Element[], changed: Set<number>) {
+  return (
+    current.length === next.length &&
+    next.every(
+      (element, index) =>
+        changed.has(index) ||
+        [...element.attributes].every(
+          (attribute) => current[index]?.getAttribute(attribute.name) === attribute.value
+        )
+    )
+  )
+}
diff --git a/priv/ts/client/hmr.ts b/priv/ts/client/hmr.ts
index 5310879..48d9a9d 100644
--- a/priv/ts/client/hmr.ts
+++ b/priv/ts/client/hmr.ts
@@ -5,7 +5,9 @@ import {
   preserveHotData,
   type HotCallback
 } from './hot'
-import { renderErrorOverlay } from './overlay'
+import { clearErrorOverlay, renderErrorOverlay, type VoltError } from './overlay'
+import { applyDocument, pageIdentity, revalidateDocument, type PushedDocument } from './document'
+import { pageReload } from './reload'
 import { removeStyle, updateStyle, updateStyles } from './styles'
 
 export { createHotContext, removeStyle, updateStyle }
@@ -19,6 +21,7 @@ let reconnectTimer: ReturnType<typeof setTimeout> | undefined
 let heartbeatTimer: ReturnType<typeof setInterval> | undefined
 let lastPongAt = 0
 let reconnectAttempts = 0
+let connected = false
 
 const HEARTBEAT_INTERVAL = __VOLT_HEARTBEAT__
 const PONG_GRACE = HEARTBEAT_INTERVAL * 2
@@ -30,8 +33,18 @@ function connect() {
   ws = new WebSocket(`${proto}//${location.host}/@volt/ws`)
 
   ws.onopen = () => {
+    // The server may have restarted while we were away, so the page can be stale.
+    if (connected) {
+      pageReload()
+      return
+    }
+
+    connected = true
     console.log('[Volt] HMR connected')
 
+    const identity = pageIdentity()
+    if (identity) ws?.send(JSON.stringify({ type: 'page', payload: identity }))
+
     if (reconnectTimer) {
       clearTimeout(reconnectTimer)
       reconnectTimer = undefined
@@ -72,13 +85,13 @@ function connect() {
         )
         break
       case 'error':
-        showOverlay(payload.reason)
+        showErrors(payload.errors as VoltError[])
         break
       case 'full-reload':
-        location.reload()
+        pageReload()
         break
       default:
-        location.reload()
+        pageReload()
         break
     }
   }
@@ -115,19 +128,37 @@ async function handleUpdate(payload: {
     return
   }
 
+  if (changes.length === 1 && changes[0] === 'document') {
+    const pushed = payload as Partial<PushedDocument>
+
+    if (typeof pushed.html === 'string' && typeof pushed.etag === 'string') {
+      applyDocument({
+        html: pushed.html,
+        etag: pushed.etag,
+        owned: pushed.owned ?? [],
+        root: pushed.root ?? {},
+        head: pushed.head ?? { remove: [], add: [] }
+      })
+    } else {
+      await revalidateDocument()
+    }
+
+    return
+  }
+
   if (changes.includes('hmr') && boundary) {
     await applyHMRUpdate(boundary, path, timestamp ?? Date.now())
     return
   }
 
-  location.reload()
+  pageReload()
 }
 
 async function applyHMRUpdate(boundary: string, changedPath: string, timestamp: number) {
   const boundaryMatch = findHotModule(boundary)
 
   if (!boundaryMatch) {
-    location.reload()
+    pageReload()
     return
   }
 
@@ -162,7 +193,7 @@ async function applyHMRUpdate(boundary: string, changedPath: string, timestamp:
     console.log(`[Volt] HMR update: ${changedUrl}`)
   } catch (err) {
     console.error(`[Volt] HMR update failed for ${changedUrl}`, err)
-    location.reload()
+    pageReload()
   }
 }
 
@@ -193,8 +224,12 @@ function importVersion(url: string, timestamp: number) {
   return import(/* @vite-ignore */ `${url}${url.includes('?') ? '&' : '?'}t=${timestamp}`)
 }
 
-function showOverlay(reason: unknown) {
-  renderErrorOverlay(reason, { title: 'Build error', dismissible: true })
+function showErrors(errors: VoltError[]) {
+  if (errors.length > 0) {
+    renderErrorOverlay(errors)
+  } else {
+    clearErrorOverlay()
+  }
 }
 
 connect()
diff --git a/priv/ts/client/hot.ts b/priv/ts/client/hot.ts
index 3951028..cd62f22 100644
--- a/priv/ts/client/hot.ts
+++ b/priv/ts/client/hot.ts
@@ -1,3 +1,5 @@
+import { pageReload } from './reload'
+
 export interface HotCallback {
   deps: string[]
   kind: 'self' | 'single' | 'multi'
@@ -65,7 +67,7 @@ export function createHotContext(ownerPath: string) {
     },
 
     invalidate() {
-      location.reload()
+      pageReload()
     },
 
     on(_event: string, _cb: (...args: unknown[]) => void) {
diff --git a/priv/ts/client/overlay.ts b/priv/ts/client/overlay.ts
index 934bb07..2a5f4e7 100644
--- a/priv/ts/client/overlay.ts
+++ b/priv/ts/client/overlay.ts
@@ -1,35 +1,181 @@
-const VOLT_ERROR_OVERLAY_ID = 'volt-error-overlay'
-const VOLT_ERROR_OVERLAY_STYLE =
-  'position:fixed;inset:0;z-index:99999;background:rgba(0,0,0,0.85);color:#ff6b6b;font:14px/1.6 monospace;padding:2em;white-space:pre-wrap;overflow:auto'
+import { html, render } from 'lit-html'
+import { unsafeHTML } from 'lit-html/directives/unsafe-html.js'
 
-type VoltErrorOverlayOptions = {
-  title?: string
-  dismissible?: boolean
+export type VoltError = {
+  title: string
+  message: string
+  file?: string | null
+  line?: number | null
+  column?: number | null
+  hint?: string | null
+  frame?: string | null
+  frame_html?: string | null
+  stack?: string | null
 }
 
-export function renderErrorOverlay(reason: unknown, options: VoltErrorOverlayOptions = {}) {
-  const title = options.title ?? 'Build error'
-  console.error(`[Volt] ${title}:\n${messageFor(reason)}`)
+const TAG = 'volt-error-overlay'
+
+// Colors from the Volt logo: purple to cyan on deep purple.
+const styles = html`<style>
+  /* Page styles beat :host rules, so the host only positions the overlay. */
+  :host {
+    display: block;
+    position: fixed;
+    inset: 0;
+    z-index: 99999;
+  }
+  .backdrop {
+    box-sizing: border-box;
+    height: 100%;
+    overflow: auto;
+    padding: 6vh 16px;
+    background: rgba(20, 8, 40, 0.72);
+    font: 14px/1.6 ui-monospace, SFMono-Regular, Menlo, monospace;
+  }
+  .panel {
+    box-sizing: border-box;
+    max-width: 960px;
+    margin: 0 auto;
+    overflow: hidden;
+    color: #ece6f7;
+    background: #1a0f2e;
+    border: 1px solid #3a2466;
+    border-radius: 10px;
+    box-shadow: 0 16px 48px rgba(10, 4, 24, 0.6);
+  }
+  .panel::before {
+    content: '';
+    display: block;
+    height: 4px;
+    background: linear-gradient(90deg, #9b3dea, #1de4ef);
+  }
+  .body {
+    padding: 20px 28px 24px;
+  }
+  h1 {
+    margin: 0;
+    font: inherit;
+    font-weight: bold;
+    color: #ff6b9a;
+  }
+  section {
+    margin-top: 1.25em;
+  }
+  .location {
+    color: #1de4ef;
+  }
+  .message {
+    color: #ff6b9a;
+    white-space: pre-wrap;
+  }
+  pre {
+    margin: 0.75em 0 0;
+    padding: 12px 16px;
+    overflow-x: auto;
+    font: inherit;
+    color: #e6edf3;
+    background: #120a22;
+    border: 1px solid #2a1a48;
+    border-radius: 6px;
+  }
+  .hint {
+    margin-top: 0.5em;
+    color: #9b3dea;
+    white-space: pre-wrap;
+  }
+  pre.stack {
+    color: #8a7aa8;
+    background: none;
+    border: none;
+    padding: 0;
+  }
+  footer {
+    margin-top: 1.5em;
+    font-size: 12px;
+    color: #8a7aa8;
+  }
+</style>`
+
+class VoltErrorOverlay extends HTMLElement {
+  private root = this.attachShadow({ mode: 'open' })
+
+  constructor() {
+    super()
+    this.addEventListener('click', (event) => {
+      const target = event.composedPath()[0]
+      if (target instanceof Element && target.classList.contains('backdrop')) this.remove()
+    })
+  }
+
+  show(errors: VoltError[]) {
+    const title = heading(errors)
+
+    render(
+      html`${styles}
+        <div class="backdrop">
+          <div class="panel">
+            <div class="body">
+            <h1>${errors.length > 1 ? `${title} · ${errors.length}` : title}</h1>
+            ${errors.map(errorTemplate)}
+            <footer>Fix the error to dismiss this overlay, or click outside it.</footer>
+          </div>
+        </div>
+      </div>`,
+      this.root
+    )
+  }
+}
+
+function errorTemplate(error: VoltError) {
+  const location = locationText(error)
+
+  return html`<section>
+    ${location ? html`<div class="location">${location}</div>` : null}
+    <div class="message">${error.message}</div>
+    ${
+      error.frame
+        ? // The dev server builds `frame_html` from escaped, syntax-highlighted source.
+          html`<pre>${error.frame_html ? unsafeHTML(error.frame_html) : error.frame}</pre>`
+        : null
+    }
+    ${error.hint ? html`<div class="hint">${error.hint}</div>` : null}
+    ${error.stack ? html`<pre class="stack">${error.stack}</pre>` : null}
+  </section>`
+}
+
+export function renderErrorOverlay(errors: VoltError[]) {
+  console.error(`[Volt] ${heading(errors)}:\n${errors.map(errorText).join('\n\n')}`)
 
   if (typeof document === 'undefined') {
     return
   }
 
-  let overlay = document.getElementById(VOLT_ERROR_OVERLAY_ID)
+  if (!customElements.get(TAG)) customElements.define(TAG, VoltErrorOverlay)
+
+  clearErrorOverlay()
+  const overlay = document.createElement(TAG) as VoltErrorOverlay
+  overlay.show(errors)
+  document.body.appendChild(overlay)
+}
 
-  if (!overlay) {
-    overlay = document.createElement('div')
-    overlay.id = VOLT_ERROR_OVERLAY_ID
-    document.body.appendChild(overlay)
+export function clearErrorOverlay() {
+  if (typeof document !== 'undefined') {
+    document.querySelector(TAG)?.remove()
   }
+}
+
+// The errors' shared title, or a neutral one when they differ.
+function heading(errors: VoltError[]) {
+  const titles = new Set(errors.map((error) => error.title))
+  return titles.size === 1 ? [...titles][0] : 'Errors'
+}
 
-  overlay.style.cssText = options.dismissible
-    ? `${VOLT_ERROR_OVERLAY_STYLE};cursor:pointer`
-    : VOLT_ERROR_OVERLAY_STYLE
-  overlay.onclick = options.dismissible ? () => overlay?.remove() : null
-  overlay.textContent = `[Volt] ${title}:\n\n${messageFor(reason)}`
+function locationText({ file, line, column }: VoltError) {
+  if (!file) return null
+  if (!line) return file
+  return column ? `${file}:${line}:${column}` : `${file}:${line}`
 }
 
-function messageFor(reason: unknown) {
-  return typeof reason === 'string' ? reason : JSON.stringify(reason, null, 2)
+function errorText(error: VoltError) {
+  return [locationText(error), error.message, error.frame, error.hint].filter(Boolean).join('\n')
 }
diff --git a/priv/ts/client/reload.ts b/priv/ts/client/reload.ts
new file mode 100644
index 0000000..8cf73df
--- /dev/null
+++ b/priv/ts/client/reload.ts
@@ -0,0 +1,10 @@
+const RELOAD_DELAY = 20
+
+let timer: ReturnType<typeof setTimeout> | undefined
+
+// One save can produce several messages that each ask for a reload, such as a
+// template that is also a Tailwind source. Reloading once covers all of them.
+export function pageReload() {
+  if (timer) clearTimeout(timer)
+  timer = setTimeout(() => location.reload(), RELOAD_DELAY)
+}
diff --git a/priv/ts/client/styles.ts b/priv/ts/client/styles.ts
index ef9509a..5c51923 100644
--- a/priv/ts/client/styles.ts
+++ b/priv/ts/client/styles.ts
@@ -1,3 +1,5 @@
+import { pageReload } from './reload'
+
 export function updateStyle(id: string, css: string) {
   let style = document.querySelector<HTMLStyleElement>(`style[data-volt-id="${id}"]`)
 
@@ -14,20 +16,40 @@ export function removeStyle(id: string) {
   document.querySelector<HTMLStyleElement>(`style[data-volt-id="${id}"]`)?.remove()
 }
 
-export async function updateStyles(path: string) {
-  const links = document.querySelectorAll<HTMLLinkElement>('link[rel="stylesheet"]')
-  let updated = false
+const outdatedLinks = new WeakSet<HTMLLinkElement>()
 
-  for (const link of links) {
-    const href = link.getAttribute('href')
+// Changing `href` in place leaves the page unstyled until the new stylesheet
+// arrives. A second tag keeps the old rules applied until the new ones load.
+function refreshLink(link: HTMLLinkElement) {
+  return new Promise<void>((resolve) => {
+    const url = new URL(link.href)
+    url.searchParams.set('t', Date.now().toString())
 
-    if (href && (href.includes(path) || path.endsWith('.css'))) {
-      const url = new URL(link.href)
-      url.searchParams.set('t', Date.now().toString())
-      link.href = url.toString()
-      updated = true
+    const next = link.cloneNode() as HTMLLinkElement
+    next.href = url.toString()
+
+    const removeOutdated = () => {
+      link.remove()
+      resolve()
     }
-  }
+
+    next.addEventListener('load', removeOutdated)
+    next.addEventListener('error', removeOutdated)
+    outdatedLinks.add(link)
+    link.after(next)
+  })
+}
+
+export async function updateStyles(path: string) {
+  const links = [...document.querySelectorAll<HTMLLinkElement>('link[rel="stylesheet"]')].filter(
+    (link) => {
+      const href = link.getAttribute('href')
+      return !outdatedLinks.has(link) && href && (href.includes(path) || path.endsWith('.css'))
+    }
+  )
+
+  await Promise.all(links.map(refreshLink))
+  let updated = links.length > 0
 
   const styles = document.querySelectorAll<HTMLStyleElement>('style[data-volt-id]')
 
@@ -43,6 +65,6 @@ export async function updateStyles(path: string) {
   }
 
   if (!updated) {
-    location.reload()
+    pageReload()
   }
 }
diff --git a/priv/ts/compilers/tailwind.ts b/priv/ts/compilers/tailwind.ts
index dad2af4..a1f1570 100644
--- a/priv/ts/compilers/tailwind.ts
+++ b/priv/ts/compilers/tailwind.ts
@@ -2,23 +2,33 @@ type BeamModuleSpec = {
   path: string
   base: string
   code: string
+  dependencies: string[]
   format: 'cjs' | 'json'
 }
 
+type Source = { base: string; pattern: string; negated: boolean }
+
 type TailwindCompiler = {
   compile: (
     css: string,
     options: {
       base: string
       from: string
-      loadStylesheet: (id: string, base?: string) => Promise<{ base: string; content: string }>
+      loadStylesheet: (
+        id: string,
+        base?: string
+      ) => Promise<{ path: string; base: string; content: string }>
       loadModule: (
         id: string,
         base?: string,
         type?: string
-      ) => Promise<{ module: unknown; base: string }>
+      ) => Promise<{ path: string; module: unknown; base: string }>
     }
-  ) => Promise<{ build: (candidates: string[]) => string }>
+  ) => Promise<{
+    build: (candidates: string[]) => string
+    root: null | 'none' | { base: string; pattern: string }
+    sources: Source[]
+  }>
   Features?: unknown
 }
 
@@ -66,62 +76,131 @@ const tailwindRuntimeSpec = Beam.callSync(
 ) as BeamModuleSpec
 const tailwindExports = requireResolvedModule(tailwindRuntimeSpec, new Map()) as TailwindCompiler
 
+const compilerContexts = new Map<number, Awaited<ReturnType<TailwindCompiler['compile']>>>()
+let nextCompilerContext = 0
+
 async function compileTailwindCss(
   inputCss: string | null,
   candidates: string[] | null,
-  base: string | null
+  base: string | null,
+  scan: { base: string; sources: Source[] } | null = null,
+  metadata = false,
+  retain = false
 ) {
+  const dependencies = new Set<string>()
   const moduleCache = new Map<string, { exports: unknown }>()
   const rootBase = normalizeBase(base, TAILWIND_DEFAULT_BASE)
   const css = inputCss === null ? '@import "tailwindcss";' : inputCss
 
-  const compiler = await tailwindExports.compile(css, {
-    base: rootBase,
-    from: 'app.css',
-    loadStylesheet: async (id, currentBase) => {
-      if (id === 'tailwindcss') {
-        return {
-          base: rootBase,
-          content:
-            '@import "tailwindcss/theme.css" layer(theme);\n@import "tailwindcss/preflight.css" layer(base);\n@import "tailwindcss/utilities.css" layer(utilities);'
+  let compiler: Awaited<ReturnType<TailwindCompiler['compile']>>
+  try {
+    compiler = await tailwindExports.compile(css, {
+      base: rootBase,
+      from: 'app.css',
+      loadStylesheet: async (id, currentBase) => {
+        if (id === 'tailwindcss') {
+          return {
+            path: path.join(TAILWIND_ROOT, 'index.css'),
+            base: rootBase,
+            content:
+              '@import "tailwindcss/theme.css" layer(theme);\n@import "tailwindcss/preflight.css" layer(base);\n@import "tailwindcss/utilities.css" layer(utilities);'
+          }
         }
-      }
 
-      if (id === 'tailwindcss/theme.css') {
-        return {
-          base: rootBase,
-          content: tailwindExports.Features ? fs.readFileSync(themeCssPath, 'utf8') : ''
+        if (id === 'tailwindcss/theme.css') {
+          return {
+            path: themeCssPath,
+            base: rootBase,
+            content: tailwindExports.Features ? fs.readFileSync(themeCssPath, 'utf8') : ''
+          }
         }
-      }
 
-      if (id === 'tailwindcss/preflight.css') {
-        return { base: rootBase, content: fs.readFileSync(preflightCssPath, 'utf8') }
-      }
+        if (id === 'tailwindcss/preflight.css') {
+          return {
+            path: preflightCssPath,
+            base: rootBase,
+            content: fs.readFileSync(preflightCssPath, 'utf8')
+          }
+        }
+
+        if (id === 'tailwindcss/utilities.css') {
+          return {
+            path: utilitiesCssPath,
+            base: rootBase,
+            content: fs.readFileSync(utilitiesCssPath, 'utf8')
+          }
+        }
 
-      if (id === 'tailwindcss/utilities.css') {
-        return { base: rootBase, content: fs.readFileSync(utilitiesCssPath, 'utf8') }
+        const stylesheet = Beam.callSync(
+          'tailwind.load_stylesheet',
+          id,
+          normalizeBase(currentBase, rootBase),
+          rootBase
+        ) as
+          | { path: string; base: string; content: string }
+          | { error: string; candidates: string[] }
+        if ('error' in stylesheet) {
+          for (const candidate of stylesheet.candidates) dependencies.add(candidate)
+          throw new Error(stylesheet.error)
+        }
+        dependencies.add(stylesheet.path)
+        return stylesheet
+      },
+      loadModule: async (id, currentBase, type) => {
+        const spec = Beam.callSync(
+          'tailwind.load_module',
+          id,
+          normalizeBase(currentBase, rootBase),
+          type ?? 'plugin'
+        ) as BeamModuleSpec | { error: string; candidates: string[] }
+
+        if ('error' in spec) {
+          for (const candidate of spec.candidates) dependencies.add(candidate)
+          throw new Error(spec.error)
+        }
+        for (const dependency of spec.dependencies) dependencies.add(dependency)
+        const mod = requireResolvedModule(spec, moduleCache)
+        return { path: spec.path, module: unwrapModule(mod), base: spec.base }
       }
+    })
+  } catch (error) {
+    if (retain) return { error: String(error), dependencies: [...dependencies].sort() }
+    throw error
+  }
 
-      return Beam.callSync(
-        'tailwind.load_stylesheet',
-        id,
-        normalizeBase(currentBase, rootBase)
-      ) as { base: string; content: string }
-    },
-    loadModule: async (id, currentBase, type) => {
-      const spec = Beam.callSync(
-        'tailwind.load_module',
-        id,
-        normalizeBase(currentBase, rootBase),
-        type ?? 'plugin'
-      ) as BeamModuleSpec
-
-      const mod = requireResolvedModule(spec, moduleCache)
-      return { module: unwrapModule(mod), base: spec.base }
+  if (scan) {
+    let automatic: Source[] = []
+    if (compiler.root === null) {
+      automatic = [{ base: scan.base, pattern: '**/*', negated: false }]
+    } else if (compiler.root !== 'none') {
+      automatic = [{ ...compiler.root, negated: false }]
     }
-  })
-
-  return compiler.build(candidates ?? [])
+    candidates = Beam.callSync('tailwind.scan', [
+      ...automatic,
+      ...scan.sources,
+      ...compiler.sources
+    ]) as string[]
+  }
+  if (retain) {
+    const id = ++nextCompilerContext
+    compilerContexts.set(id, compiler)
+    return {
+      id,
+      code: '',
+      dependencies: [...dependencies].sort(),
+      sources: compiler.sources,
+      root: compiler.root
+    }
+  }
+  const code = compiler.build(candidates ?? [])
+  return metadata
+    ? {
+        code,
+        dependencies: [...dependencies].sort(),
+        sources: compiler.sources,
+        root: compiler.root
+      }
+    : code
 }
 
 function normalizeBase(base: string | null | undefined, fallbackBase: string) {
@@ -197,4 +276,20 @@ function loadCommonJSModule(
   }
 }
 
+async function prepareTailwindContext(css: string | null, base: string) {
+  return compileTailwindCss(css, [], base, null, true, true)
+}
+function buildTailwindContext(id: number, candidates: string[]) {
+  const compiler = compilerContexts.get(id)
+  if (!compiler) throw new Error('Unknown Tailwind compiler context')
+  return compiler.build(candidates)
+}
+function releaseTailwindContext(id: number) {
+  return compilerContexts.delete(id)
+}
+
+globalThis.prepareTailwindContext = prepareTailwindContext
+globalThis.buildTailwindContext = buildTailwindContext
+globalThis.releaseTailwindContext = releaseTailwindContext
+
 globalThis.compileTailwindCss = compileTailwindCss
diff --git a/priv/ts/npm.lock b/priv/ts/npm.lock
new file mode 100644
index 0000000..a7a660f
--- /dev/null
+++ b/priv/ts/npm.lock
@@ -0,0 +1,39 @@
+{
+  "lockfileVersion": 1,
+  "packages": {
+    "@types/trusted-types": {
+      "dependencies": {},
+      "has_install_script": false,
+      "integrity": "sha512-ScaPdn1dQczgbl0QFTeTOmVHFULt394XJgOQNoyVhZ6r2vLnMLJfBPd53SB52T/3G36VI1/g2MZaX0cwDuXsfw==",
+      "optional_dependencies": {},
+      "tarball": "https://registry.npmjs.org/@types/trusted-types/-/trusted-types-2.0.7.tgz",
+      "version": "2.0.7"
+    },
+    "idiomorph": {
+      "dependencies": {},
+      "has_install_script": false,
+      "integrity": "sha512-R47JBL+6jHDQvcnbppIUtXXcxi5h6+wuCEEZXnRhUltsgzPFKzThL5PuHppP9ypJuy+7WawcY1TsSBD/iQbMhw==",
+      "optional_dependencies": {},
+      "tarball": "https://registry.npmjs.org/idiomorph/-/idiomorph-0.8.0.tgz",
+      "version": "0.8.0"
+    },
+    "lit-html": {
+      "dependencies": {
+        "@types/trusted-types": "^2.0.2"
+      },
+      "has_install_script": false,
+      "integrity": "sha512-el8M6jK2o3RXBnrSHX3ZKrsN8zEV63pSExTO1wYJz7QndGYZ8353e2a5PPX+qHe2aGayfnchQmkAojaWAREOIA==",
+      "optional_dependencies": {},
+      "tarball": "https://registry.npmjs.org/lit-html/-/lit-html-3.3.3.tgz",
+      "version": "3.3.3"
+    }
+  },
+  "policy": {
+    "allow_registry_redirects": false,
+    "allowed_registries": [
+      "https://registry.npmjs.org"
+    ],
+    "block_exotic_subdeps": true,
+    "exotic_deps": []
+  }
+}
diff --git a/priv/ts/package.json b/priv/ts/package.json
new file mode 100644
index 0000000..5000e87
--- /dev/null
+++ b/priv/ts/package.json
@@ -0,0 +1,7 @@
+{
+  "private": true,
+  "dependencies": {
+    "idiomorph": "0.8.0",
+    "lit-html": "3.3.3"
+  }
+}
diff --git a/priv/ts/test/entry.ts b/priv/ts/test/entry.ts
new file mode 100644
index 0000000..f6b21b1
--- /dev/null
+++ b/priv/ts/test/entry.ts
@@ -0,0 +1 @@
+$imports
diff --git a/priv/ts/test/runner.ts b/priv/ts/test/runner.ts
index fa23913..508943b 100644
--- a/priv/ts/test/runner.ts
+++ b/priv/ts/test/runner.ts
@@ -2,6 +2,8 @@ import { SkipError, serializeError } from './errors'
 import { expect } from './matchers'
 import { reset, state } from './state'
 
+const now = Date.now.bind(Date)
+
 export async function __voltCollectTestModule(code: string, file: string) {
   loadTestModule(code, file)
 
@@ -32,12 +34,12 @@ export async function __voltRunLoadedTestModule(
 
 async function runLoadedTests(file: string, onlyId?: number) {
   const results: Volt.Test.Result[] = []
-  const startedAt = Date.now()
+  const startedAt = now()
   const tests =
     onlyId === undefined ? state.tests : state.tests.filter((test) => test.id === onlyId)
 
   for (const registered of tests) {
-    const testStartedAt = Date.now()
+    const testStartedAt = now()
 
     if (registered.mode !== 'run') {
       results.push(result(registered, 'skipped', testStartedAt, undefined, registered.skipReason))
@@ -65,7 +67,7 @@ async function runLoadedTests(file: string, onlyId?: number) {
   return {
     file,
     status: failed === 0 ? 'passed' : 'failed',
-    duration: Date.now() - startedAt,
+    duration: now() - startedAt,
     total: results.length,
     failed,
     skipped,
@@ -127,7 +129,7 @@ function result(
     name: registered.name,
     fullName: fullName(registered),
     status,
-    duration: Date.now() - startedAt,
+    duration: now() - startedAt,
     ...(error ? { error } : {}),
     ...(skipReason ? { skipReason } : {})
   }
diff --git a/priv/ts/test/template-globals.d.ts b/priv/ts/test/template-globals.d.ts
new file mode 100644
index 0000000..aaf1db3
--- /dev/null
+++ b/priv/ts/test/template-globals.d.ts
@@ -0,0 +1 @@
+declare const $imports: unknown
diff --git a/priv/types/client/env.d.ts b/priv/types/client/env.d.ts
new file mode 100644
index 0000000..5ef2d2d
--- /dev/null
+++ b/priv/types/client/env.d.ts
@@ -0,0 +1,10 @@
+interface ImportMetaEnv {
+  readonly MODE: string
+  readonly DEV: boolean
+  readonly PROD: boolean
+  readonly [key: string]: string | boolean | undefined
+}
+
+interface ImportMeta {
+  readonly env: ImportMetaEnv
+}
diff --git a/priv/types/client/styles.d.ts b/priv/types/client/styles.d.ts
new file mode 100644
index 0000000..38f6005
--- /dev/null
+++ b/priv/types/client/styles.d.ts
@@ -0,0 +1,6 @@
+declare module "*.module.css" {
+  const classes: Readonly<Record<string, string>>;
+  export default classes;
+}
+
+declare module "*.css" {}
diff --git a/scripts/postinstall.mjs b/scripts/postinstall.mjs
new file mode 100644
index 0000000..c3d3707
--- /dev/null
+++ b/scripts/postinstall.mjs
@@ -0,0 +1,14 @@
+import { chmodSync, existsSync, readdirSync } from "node:fs";
+import { join } from "node:path";
+
+if (process.platform !== "win32") {
+  const packageRoot = "node_modules/@oxlint-tsgolint";
+
+  for (const directory of readdirSync(packageRoot)) {
+    const executable = join(packageRoot, directory, "tsgolint");
+
+    if (existsSync(executable)) {
+      chmodSync(executable, 0o755);
+    }
+  }
+}
diff --git a/scripts/update_runtime_locks.exs b/scripts/update_runtime_locks.exs
new file mode 100644
index 0000000..bab34b3
--- /dev/null
+++ b/scripts/update_runtime_locks.exs
@@ -0,0 +1,62 @@
+Logger.configure(level: :warning)
+
+alias Volt.JS.Runtime.Installer
+
+sets = [
+  Volt.Plugin.Svelte.runtime_package_set(),
+  Volt.Plugin.Solid.runtime_package_set(),
+  Volt.Tailwind.Loader.runtime_package_set()
+]
+
+{opts, args} = OptionParser.parse!(System.argv(), strict: [only: :keep])
+
+if args != [] do
+  raise ArgumentError, "unexpected arguments: #{Enum.join(args, " ")}"
+end
+
+requested = opts |> Keyword.get_values(:only) |> MapSet.new()
+
+selected =
+  if MapSet.size(requested) == 0 do
+    sets
+  else
+    Enum.filter(sets, &MapSet.member?(requested, Atom.to_string(&1.name)))
+  end
+
+found = selected |> Enum.map(&Atom.to_string(&1.name)) |> MapSet.new()
+missing = MapSet.difference(requested, found)
+
+if MapSet.size(missing) > 0 do
+  raise ArgumentError,
+        "unknown runtime package sets: #{missing |> Enum.sort() |> Enum.join(", ")}"
+end
+
+tmp_dir =
+  Path.join(
+    System.tmp_dir!(),
+    "volt-runtime-locks-#{System.unique_integer([:positive])}"
+  )
+
+File.mkdir_p!(tmp_dir)
+
+try do
+  Enum.each(selected, fn set ->
+    install =
+      Installer.install!(set.packages,
+        install_dir: Path.join(tmp_dir, Atom.to_string(set.name)),
+        force: true
+      )
+
+    generated = Path.join(install.install_dir, "npm.lock")
+    target = Path.expand("../priv/npm/#{set.name}.lock", __DIR__)
+    File.mkdir_p!(Path.dirname(target))
+    File.cp!(generated, target)
+
+    digest =
+      target |> File.read!() |> then(&:crypto.hash(:sha256, &1)) |> Base.encode16(case: :lower)
+
+    Mix.shell().info("Updated #{Path.relative_to_cwd(target)} (sha256: #{digest})")
+  end)
+after
+  File.rm_rf!(tmp_dir)
+end
diff --git a/test/mix/tasks/volt.js.check_test.exs b/test/mix/tasks/volt.js.check_test.exs
deleted file mode 100644
index 39484c3..0000000
--- a/test/mix/tasks/volt.js.check_test.exs
+++ /dev/null
@@ -1,182 +0,0 @@
-defmodule Volt.JsCheckTest do
-  use ExUnit.Case, async: false
-
-  import ExUnit.CaptureIO
-
-  @tmp_dir "tmp/js_check_test_#{:erlang.unique_integer([:positive])}"
-
-  setup do
-    File.mkdir_p!(@tmp_dir)
-    on_exit(fn -> File.rm_rf!(@tmp_dir) end)
-    original_root = Application.get_env(:volt, :root)
-    original_lint = Application.get_env(:volt, :lint)
-    original_sources = Application.get_env(:volt, :sources)
-    Application.put_env(:volt, :root, @tmp_dir)
-
-    on_exit(fn ->
-      if original_root,
-        do: Application.put_env(:volt, :root, original_root),
-        else: Application.delete_env(:volt, :root)
-
-      if original_lint,
-        do: Application.put_env(:volt, :lint, original_lint),
-        else: Application.delete_env(:volt, :lint)
-
-      if original_sources,
-        do: Application.put_env(:volt, :sources, original_sources),
-        else: Application.delete_env(:volt, :sources)
-    end)
-
-    :ok
-  end
-
-  test "reports parser errors in syntax lint mode" do
-    File.write!(Path.join(@tmp_dir, "broken.ts"), "const = ;\n")
-
-    output =
-      capture_io(:stderr, fn ->
-        catch_exit(Mix.Tasks.Volt.Js.Check.run([]))
-      end)
-
-    assert output =~ "error"
-    assert output =~ "broken.ts"
-  end
-
-  test "type-aware check reports tsgolint diagnostics" do
-    File.write!(Path.join(@tmp_dir, "typed.ts"), "export const value = Promise.resolve(1)\n")
-    tsgolint = fake_tsgolint!(@tmp_dir)
-
-    Application.put_env(:volt, :lint,
-      tsgolint: tsgolint,
-      rules: %{"typescript/no-floating-promises" => :deny}
-    )
-
-    output =
-      capture_io(:stderr, fn ->
-        catch_exit(Mix.Tasks.Volt.Js.Check.run(["--type-aware"]))
-      end)
-
-    assert output =~ "floating promise"
-    assert output =~ "typescript/no-floating-promises"
-  end
-
-  test "type-check diagnostics are promoted to errors" do
-    diagnostic = %{
-      rule: "typescript/TS2322",
-      severity: :warn,
-      file: "typed.ts",
-      message: "Type number is not assignable to type string."
-    }
-
-    assert %{severity: :deny} =
-             Volt.JS.Check.promote_type_check_diagnostic(diagnostic, type_check: true)
-  end
-
-  test "type-aware check keeps Oxlint-style rules and retries without unsupported tsgolint rules" do
-    File.write!(Path.join(@tmp_dir, "typed.ts"), "export const value = 1\n")
-    tsgolint = fake_tsgolint_unknown_retry!(@tmp_dir)
-
-    Application.put_env(:volt, :lint,
-      tsgolint: tsgolint,
-      rules: %{
-        "correctness" => :deny,
-        "suspicious" => :deny,
-        "no-console" => :warn,
-        "typescript/consistent-type-imports" => :deny,
-        "typescript/no-floating-promises" => :warn
-      }
-    )
-
-    capture_io(fn ->
-      Mix.Tasks.Volt.Js.Check.run(["--type-aware"])
-    end)
-
-    payload = @tmp_dir |> Path.join("payload.json") |> File.read!() |> Jason.decode!()
-    assert [%{"rules" => [%{"name" => "no-floating-promises"}]}] = payload["configs"]
-  end
-
-  test "type-aware check submits framework single-file component scripts as virtual files" do
-    File.write!(Path.join(@tmp_dir, "app.ts"), "import './Component.vue'\n")
-
-    File.write!(
-      Path.join(@tmp_dir, "Component.vue"),
-      "<script setup lang=\"ts\">const vueValue: string = 'ok'</script>\n"
-    )
-
-    File.write!(
-      Path.join(@tmp_dir, "Widget.svelte"),
-      "<script lang=\"ts\">const svelteValue: string = 'ok'</script>\n"
-    )
-
-    tsgolint = fake_tsgolint_capture!(@tmp_dir)
-
-    Application.put_env(:volt, :sources, ["**/*.{js,ts,jsx,tsx,vue,svelte}"])
-
-    Application.put_env(:volt, :lint,
-      tsgolint: tsgolint,
-      rules: %{"typescript/no-floating-promises" => :deny}
-    )
-
-    capture_io(fn ->
-      Mix.Tasks.Volt.Js.Check.run(["--type-aware"])
-    end)
-
-    payload = @tmp_dir |> Path.join("payload.json") |> File.read!() |> Jason.decode!()
-    assert [%{"file_paths" => file_paths}] = payload["configs"]
-    basenames = Enum.map(file_paths, &Path.basename/1)
-
-    assert "app.ts" in basenames
-    assert "Component.vue.script0.ts" in basenames
-    assert "Widget.svelte.script0.ts" in basenames
-
-    overrides = payload["source_overrides"]
-    assert overrides[Path.expand(Path.join(@tmp_dir, "Component.vue.script0.ts"))] =~ "vueValue"
-
-    assert overrides[Path.expand(Path.join(@tmp_dir, "Widget.svelte.script0.ts"))] =~
-             "svelteValue"
-  end
-
-  defp fake_tsgolint!(dir) do
-    path = Path.join(dir, "tsgolint")
-
-    File.write!(path, """
-    #!/bin/sh
-    elixir -e 'json = ~s({"rule":"no-floating-promises","message":{"description":"floating promise"},"file_path":"typed.ts","range":{"pos":0,"end":5}}); size = byte_size(json); File.write!("/dev/stdout", <<size::32-little, 1, json::binary>>)'
-    """)
-
-    File.chmod!(path, 0o755)
-    path
-  end
-
-  defp fake_tsgolint_capture!(dir) do
-    path = Path.join(dir, "tsgolint-capture")
-    payload_path = Path.join(dir, "payload.json")
-
-    File.write!(path, """
-    #!/bin/sh
-    cat > #{payload_path}
-    """)
-
-    File.chmod!(path, 0o755)
-    path
-  end
-
-  defp fake_tsgolint_unknown_retry!(dir) do
-    path = Path.join(dir, "tsgolint-unknown-retry")
-    payload_path = Path.join(dir, "payload.json")
-    input_path = Path.join(dir, "payload-attempt.json")
-
-    File.write!(path, """
-    #!/bin/sh
-    cat > #{input_path}
-    if grep -q consistent-type-imports #{input_path}; then
-      echo 'panic: unknown rule: consistent-type-imports [recovered, repanicked]' >&2
-      exit 2
-    fi
-    cp #{input_path} #{payload_path}
-    """)
-
-    File.chmod!(path, 0o755)
-    path
-  end
-end
diff --git a/test/mix/tasks/volt.lint_test.exs b/test/mix/tasks/volt.lint_test.exs
deleted file mode 100644
index b77e38a..0000000
--- a/test/mix/tasks/volt.lint_test.exs
+++ /dev/null
@@ -1,130 +0,0 @@
-defmodule Volt.LintTest do
-  use ExUnit.Case, async: false
-
-  import ExUnit.CaptureIO
-
-  @tmp_dir "tmp/lint_test_#{:erlang.unique_integer([:positive])}"
-
-  setup do
-    File.mkdir_p!(@tmp_dir)
-    on_exit(fn -> File.rm_rf!(@tmp_dir) end)
-    original_root = Application.get_env(:volt, :root)
-    original_lint = Application.get_env(:volt, :lint)
-    Application.put_env(:volt, :root, @tmp_dir)
-
-    on_exit(fn ->
-      if original_root,
-        do: Application.put_env(:volt, :root, original_root),
-        else: Application.delete_env(:volt, :root)
-
-      if original_lint,
-        do: Application.put_env(:volt, :lint, original_lint),
-        else: Application.delete_env(:volt, :lint)
-    end)
-
-    :ok
-  end
-
-  test "reports no issues for clean code" do
-    File.write!(Path.join(@tmp_dir, "clean.ts"), "export const x = 1;\n")
-    Application.put_env(:volt, :lint, plugins: [:typescript])
-
-    output = capture_io(fn -> Mix.Tasks.Volt.Lint.run([]) end)
-    assert output =~ "No issues found"
-  end
-
-  test "detects eqeqeq violation" do
-    File.write!(Path.join(@tmp_dir, "bad.js"), "export const y = x == 1;\n")
-    Application.put_env(:volt, :lint, rules: %{"eqeqeq" => :deny})
-
-    output =
-      capture_io(fn ->
-        catch_exit(Mix.Tasks.Volt.Lint.run([]))
-      end)
-
-    assert output =~ "eqeqeq"
-    assert output =~ "error"
-  end
-
-  test "detects typescript rule" do
-    File.write!(Path.join(@tmp_dir, "typed.ts"), "export function foo(x: any) { return x; }\n")
-
-    Application.put_env(:volt, :lint,
-      plugins: [:typescript],
-      rules: %{"typescript/no-explicit-any" => :warn}
-    )
-
-    output = capture_io(fn -> Mix.Tasks.Volt.Lint.run([]) end)
-    assert output =~ "no-explicit-any"
-  end
-
-  test "CLI --plugin flag overrides config" do
-    File.write!(Path.join(@tmp_dir, "typed.ts"), "export function foo(x: any) { return x; }\n")
-
-    Application.put_env(:volt, :lint,
-      plugins: [],
-      rules: %{"typescript/no-explicit-any" => :warn}
-    )
-
-    output = capture_io(fn -> Mix.Tasks.Volt.Lint.run(["--plugin", "typescript"]) end)
-    assert output =~ "no-explicit-any"
-  end
-
-  test "skips node_modules" do
-    File.mkdir_p!(Path.join(@tmp_dir, "node_modules/pkg"))
-    File.write!(Path.join([@tmp_dir, "node_modules", "pkg", "bad.js"]), "debugger;\n")
-    Application.put_env(:volt, :lint, rules: %{"no-debugger" => :deny})
-
-    output = capture_io(fn -> Mix.Tasks.Volt.Lint.run([]) end)
-    assert output =~ "No lintable files"
-  end
-
-  test "reports correct file location" do
-    File.write!(Path.join(@tmp_dir, "loc.js"), "const a = 1;\nexport const b = x == y;\n")
-    Application.put_env(:volt, :lint, rules: %{"eqeqeq" => :deny})
-
-    output =
-      capture_io(fn ->
-        catch_exit(Mix.Tasks.Volt.Lint.run([]))
-      end)
-
-    assert output =~ "loc.js:2:"
-  end
-
-  test "custom rules via config" do
-    defmodule TestNoDebugger do
-      @behaviour OXC.Lint.Rule
-
-      @impl true
-      def meta,
-        do: %{
-          name: "test/no-debugger-custom",
-          description: "custom",
-          category: :correctness,
-          fixable: false
-        }
-
-      @impl true
-      def run(ast, _ctx) do
-        OXC.collect(ast, fn
-          %{type: :debugger_statement, start: s, end: e} ->
-            {:keep, %{span: {s, e}, message: "custom debugger ban"}}
-
-          _ ->
-            :skip
-        end)
-      end
-    end
-
-    File.write!(Path.join(@tmp_dir, "dbg.js"), "export function f() { debugger; }\n")
-    Application.put_env(:volt, :lint, custom_rules: [{TestNoDebugger, :deny}])
-
-    output =
-      capture_io(fn ->
-        catch_exit(Mix.Tasks.Volt.Lint.run([]))
-      end)
-
-    assert output =~ "custom debugger ban"
-    assert output =~ "test/no-debugger-custom"
-  end
-end
diff --git a/test/mix/tasks/volt.build_test.exs b/test/mix/tasks/volt/build_test.exs
similarity index 54%
rename from test/mix/tasks/volt.build_test.exs
rename to test/mix/tasks/volt/build_test.exs
index c9a04ab..bae2688 100644
--- a/test/mix/tasks/volt.build_test.exs
+++ b/test/mix/tasks/volt/build_test.exs
@@ -7,7 +7,7 @@ defmodule Mix.Tasks.Volt.BuildTest do
     Mix.Task.reenable("volt.build")
 
     tmp_dir =
-      Path.join(System.tmp_dir!(), "volt-build-test-#{System.unique_integer([:positive])}")
+      Path.expand("volt-build-test-#{System.unique_integer([:positive])}", System.tmp_dir!())
 
     File.mkdir_p!(Path.join(tmp_dir, "src"))
 
@@ -20,6 +20,87 @@ defmodule Mix.Tasks.Volt.BuildTest do
     {:ok, tmp_dir: tmp_dir}
   end
 
+  test "explicit Tailwind enablement works without configured roots", %{tmp_dir: root} do
+    original = Application.get_env(:volt, :tailwind)
+    Application.put_env(:volt, :tailwind, [])
+
+    on_exit(fn ->
+      if is_nil(original),
+        do: Application.delete_env(:volt, :tailwind),
+        else: Application.put_env(:volt, :tailwind, original)
+    end)
+
+    entry = Path.join(root, "src/app.js")
+    File.write!(entry, "console.log('ready')")
+    css = Path.join(root, "src/custom.css")
+    File.write!(css, "@import 'tailwindcss' source(none); .custom { color: red }")
+
+    for {name, flags, expected} <- [
+          {"default", ["--tailwind"], "app.css"},
+          {"custom", ["--tailwind-css", css], "custom.css"},
+          {"disabled", ["--tailwind-css", css, "--no-tailwind"], nil}
+        ] do
+      outdir = Path.join(root, name)
+
+      try do
+        Mix.Tasks.Volt.Build.run(
+          ["--entry", entry, "--outdir", outdir, "--no-hash", "--no-minify"] ++ flags
+        )
+      catch
+        :exit, reason ->
+          receive do
+            {:mix_shell, :error, [message]} -> flunk("#{name}: #{message}")
+          after
+            0 -> exit(reason)
+          end
+      end
+
+      styles = Path.wildcard(Path.join(outdir, "css/*.css"))
+      assert Enum.map(styles, &Path.basename/1) == List.wrap(expected)
+    end
+  end
+
+  test "nested flat assets preserve CDN URLs and sourcemaps", %{tmp_dir: root} do
+    entry = Path.join(root, "src/app.js")
+    File.write!(Path.join(root, "src/logo.svg"), "<svg/>")
+    File.write!(Path.join(root, "src/style.css"), ".logo { background: url('./logo.svg') }")
+
+    File.write!(
+      entry,
+      "import logo from './logo.svg?url'; import './style.css'; console.log(logo)"
+    )
+
+    outdir = Path.join(root, "dist")
+
+    Mix.Tasks.Volt.Build.run([
+      "--entry",
+      entry,
+      "--outdir",
+      outdir,
+      "--assets-dir",
+      "assets",
+      "--output-layout",
+      "flat",
+      "--no-hash",
+      "--no-minify",
+      "--no-tailwind",
+      "--asset-url-prefix",
+      "https://cdn.example/site",
+      "--sourcemap",
+      "true"
+    ])
+
+    manifest = outdir |> Path.join("manifest.json") |> File.read!() |> Jason.decode!()
+    js = File.read!(Path.join(outdir, manifest["app.js"]["file"]))
+    css = File.read!(Path.join(outdir, manifest["app.css"]["file"]))
+    assert [image] = Path.wildcard(Path.join(outdir, "assets/logo-*.svg"))
+    url = "https://cdn.example/site/assets/" <> Path.basename(image)
+    assert js =~ url
+    assert css =~ url
+    assert js =~ "sourceMappingURL=app.js.map"
+    assert File.regular?(Path.join(outdir, "assets/app.js.map"))
+  end
+
   test "--no-tree-shaking is accepted", %{tmp_dir: tmp_dir} do
     entry = Path.join(tmp_dir, "src/app.js")
     outdir = Path.join(tmp_dir, "dist")
@@ -81,7 +162,7 @@ defmodule Mix.Tasks.Volt.BuildTest do
     ])
 
     js_path = Path.join([outdir, "js", "app.js"])
-    assert File.read!(js_path) =~ ~r(/cdn/assets/logo-[a-f0-9]{8}\.svg)
+    assert File.read!(js_path) =~ ~r(/cdn/assets/js/logo-[a-f0-9]{8}\.svg)
   end
 
   test "--sourcemap false disables production sourcemaps", %{tmp_dir: tmp_dir} do
@@ -142,11 +223,10 @@ defmodule Mix.Tasks.Volt.BuildTest do
 
     Mix.Tasks.Volt.Build.run(["--tailwind"])
 
-    css_manifest = outdir |> Path.join("css/manifest.json") |> File.read!() |> Jason.decode!()
+    manifest = outdir |> Path.join("manifest.json") |> File.read!() |> Jason.decode!()
 
-    assert File.regular?(Path.join([outdir, "css", "app.css"]))
-    assert File.regular?(Path.join([outdir, "js", "app.js"]))
-    assert css_manifest["app.css"]["file"] == "app.css"
+    assert manifest["app.css"]["file"] == "css/app.css"
+    assert manifest["app.js"]["file"] == "js/app.js"
 
     refute outdir
            |> Path.join("css")
diff --git a/test/mix/tasks/volt.install_test.exs b/test/mix/tasks/volt/install_test.exs
similarity index 56%
rename from test/mix/tasks/volt.install_test.exs
rename to test/mix/tasks/volt/install_test.exs
index 3960df2..74b913c 100644
--- a/test/mix/tasks/volt.install_test.exs
+++ b/test/mix/tasks/volt/install_test.exs
@@ -1,4 +1,4 @@
-defmodule Volt.InstallTest do
+defmodule Mix.Tasks.Volt.InstallTest do
   use ExUnit.Case
 
   alias Igniter.Test
@@ -110,6 +110,16 @@ defmodule Volt.InstallTest do
 
       refute config_content =~ "config :esbuild"
       refute config_content =~ "config :tailwind"
+      refute config_content =~ "semi:"
+
+      {formatter_opts, _binding} =
+        igniter.rewrite.sources[".formatter.exs"]
+        |> Rewrite.Source.get(:content)
+        |> Code.eval_string()
+
+      assert Volt.Formatter in formatter_opts[:plugins]
+      assert formatter_opts[:volt][:semi] == false
+      assert formatter_opts[:volt][:trailing_comma] == :none
 
       dev_content =
         igniter.rewrite.sources["config/dev.exs"]
@@ -132,9 +142,87 @@ defmodule Volt.InstallTest do
         igniter.rewrite.sources["mix.exs"]
         |> Rewrite.Source.get(:content)
 
+      tsconfig =
+        igniter.rewrite.sources["tsconfig.json"]
+        |> Rewrite.Source.get(:content)
+        |> Jason.decode!()
+
+      assert tsconfig["compilerOptions"]["strict"]
+      assert "deps/volt/priv/types/client/**/*.d.ts" in tsconfig["include"]
+
       assert mix_content =~ ~s("assets.setup": [])
       assert mix_content =~ ~s("assets.build": ["compile", "volt.build --tailwind"])
       assert mix_content =~ ~s("assets.deploy": ["volt.build --tailwind", "phx.digest"])
     end
+
+    test "preserves options, exclusions and explicit files while adding client types once" do
+      original = %{
+        "compilerOptions" => %{"strict" => false},
+        "exclude" => ["deps"],
+        "files" => ["assets/app.ts"]
+      }
+
+      igniter = install_with_config("tsconfig.json", Jason.encode!(original))
+      config = config(igniter, "tsconfig.json")
+      assert config["compilerOptions"] == original["compilerOptions"]
+      assert config["exclude"] == ["deps"]
+      refute Map.has_key?(config, "include")
+
+      assert config["files"] == [
+               "assets/app.ts",
+               "deps/volt/priv/types/client/env.d.ts",
+               "deps/volt/priv/types/client/hmr.d.ts",
+               "deps/volt/priv/types/client/preload.d.ts",
+               "deps/volt/priv/types/client/styles.d.ts"
+             ]
+
+      assert config(Mix.Tasks.Volt.Install.igniter(igniter), "tsconfig.json") == config
+    end
+
+    test "retains default source discovery when adding explicit declaration files" do
+      config =
+        install_with_config("tsconfig.json", ~s({"compilerOptions":{"strict":true}}))
+        |> config("tsconfig.json")
+
+      assert config["include"] == ["**/*"]
+    end
+
+    test "keeps an authored include list" do
+      config =
+        install_with_config("tsconfig.json", ~s({"include":["src/**/*.ts"]}))
+        |> config("tsconfig.json")
+
+      assert config["include"] == ["src/**/*.ts"]
+    end
+
+    test "updates an assets configuration with paths relative to that configuration" do
+      igniter = install_with_config("assets/tsconfig.json", ~s({"include":["**/*.ts"]}))
+      refute Map.has_key?(igniter.rewrite.sources, "tsconfig.json")
+
+      assert "../deps/volt/priv/types/client/hmr.d.ts" in config(igniter, "assets/tsconfig.json")[
+               "files"
+             ]
+    end
+
+    test "leaves JSONC and inherited or referenced configurations untouched with guidance" do
+      for content <- [
+            "{ // preserve this comment\n}",
+            ~s({"extends":"./base.json"}),
+            ~s({"references":[{"path":"./assets"}]})
+          ] do
+        igniter = install_with_config("tsconfig.json", content)
+        assert Rewrite.Source.get(igniter.rewrite.sources["tsconfig.json"], :content) == content
+        assert Enum.any?(igniter.warnings, &String.contains?(&1, "manual configuration"))
+      end
+    end
+  end
+
+  defp install_with_config(path, content) do
+    Test.test_project(app_name: :demo, files: %{path => content})
+    |> Mix.Tasks.Volt.Install.igniter()
+  end
+
+  defp config(igniter, path) do
+    igniter.rewrite.sources[path] |> Rewrite.Source.get(:content) |> Jason.decode!()
   end
 end
diff --git a/test/mix/tasks/volt/js/check_test.exs b/test/mix/tasks/volt/js/check_test.exs
new file mode 100644
index 0000000..9c702a1
--- /dev/null
+++ b/test/mix/tasks/volt/js/check_test.exs
@@ -0,0 +1,451 @@
+defmodule Mix.Tasks.Volt.Js.CheckTest do
+  use ExUnit.Case, async: false
+
+  import ExUnit.CaptureIO
+
+  @tmp_dir "tmp/js_check_test_#{:erlang.unique_integer([:positive])}"
+
+  setup do
+    File.mkdir_p!(@tmp_dir)
+    on_exit(fn -> File.rm_rf!(@tmp_dir) end)
+    original_root = Application.get_env(:volt, :root)
+    original_lint = Application.get_env(:volt, :lint)
+    original_sources = Application.get_env(:volt, :sources)
+    Application.put_env(:volt, :root, @tmp_dir)
+
+    on_exit(fn ->
+      if original_root,
+        do: Application.put_env(:volt, :root, original_root),
+        else: Application.delete_env(:volt, :root)
+
+      if original_lint,
+        do: Application.put_env(:volt, :lint, original_lint),
+        else: Application.delete_env(:volt, :lint)
+
+      if original_sources,
+        do: Application.put_env(:volt, :sources, original_sources),
+        else: Application.delete_env(:volt, :sources)
+    end)
+
+    :ok
+  end
+
+  test "reports parser errors in syntax lint mode" do
+    File.write!(Path.join(@tmp_dir, "broken.ts"), "const = ;\n")
+
+    output =
+      capture_io(:stderr, fn ->
+        catch_exit(Mix.Tasks.Volt.Js.Check.run([]))
+      end)
+
+    assert output =~ "error"
+    assert output =~ "broken.ts"
+  end
+
+  test "syntax lint recognizes configured globals" do
+    file = Path.join(@tmp_dir, "globals.js")
+    File.write!(file, "document; describe; knownGlobal(); missingGlobal();\n")
+
+    Application.put_env(:volt, :lint,
+      env: ["browser", "mocha"],
+      globals: %{"knownGlobal" => :readonly},
+      rules: %{"no-undef" => :deny}
+    )
+
+    diagnostics = Volt.JS.Check.lint([file])
+
+    assert Enum.any?(diagnostics, &(&1.message =~ "missingGlobal"))
+    refute Enum.any?(diagnostics, &(&1.message =~ "document"))
+    refute Enum.any?(diagnostics, &(&1.message =~ "describe"))
+    refute Enum.any?(diagnostics, &(&1.message =~ "knownGlobal"))
+  end
+
+  test "type-aware check reports tsgolint diagnostics" do
+    File.write!(Path.join(@tmp_dir, "typed.ts"), "export const value = Promise.resolve(1)\n")
+    tsgolint = fake_tsgolint!(@tmp_dir)
+
+    Application.put_env(:volt, :lint,
+      tsgolint: tsgolint,
+      rules: %{"typescript/no-floating-promises" => :deny}
+    )
+
+    output =
+      capture_io(:stderr, fn ->
+        catch_exit(Mix.Tasks.Volt.Js.Check.run(["--type-aware"]))
+      end)
+
+    assert output =~ "floating promise"
+    assert output =~ "typescript/no-floating-promises"
+  end
+
+  test "category-only configuration submits semantic rules to tsgolint" do
+    file = Path.join(@tmp_dir, "typed.ts")
+    File.write!(file, "Promise.resolve(1);\n")
+
+    Application.put_env(:volt, :lint,
+      tsgolint: fake_tsgolint!(@tmp_dir),
+      plugins: ["typescript"],
+      rules: %{"correctness" => :deny}
+    )
+
+    diagnostics = Volt.JS.Check.lint([file], type_aware: true)
+
+    assert Enum.any?(
+             diagnostics,
+             &(&1.rule == "typescript/no-floating-promises" and &1.severity == :error)
+           )
+  end
+
+  test "category expansion honors per-file semantic rule exclusions" do
+    first = Path.join(@tmp_dir, "first.ts")
+    second = Path.join(@tmp_dir, "second.ts")
+    Enum.each([first, second], &File.write!(&1, "Promise.resolve(1);\n"))
+    payload_path = Path.join(@tmp_dir, "categories.jsonl")
+
+    tsgolint =
+      fake_executable!(@tmp_dir, "tsgolint-categories", """
+      input = IO.binread(:stdio, :eof)
+      File.write!(#{inspect(payload_path)}, [input, "\\n"], [:append])
+      """)
+
+    Application.put_env(:volt, :lint,
+      root: @tmp_dir,
+      tsgolint: tsgolint,
+      plugins: ["typescript"],
+      rules: %{"correctness" => :deny},
+      overrides: [%{files: ["second.ts"], rules: %{"typescript/no-floating-promises" => :allow}}]
+    )
+
+    assert [] = Volt.JS.Check.lint([first, second], type_aware: true)
+    batches = payload_path |> File.stream!() |> Enum.map(&Jason.decode!/1)
+    configs = Enum.flat_map(batches, & &1["configs"])
+
+    for {file, selected} <- [{first, true}, {second, false}] do
+      config = Enum.find(configs, &(Path.expand(file) in &1["file_paths"]))
+      assert Enum.any?(config["rules"], &(&1["name"] == "no-floating-promises")) == selected
+    end
+  end
+
+  test "type-check diagnostics are promoted to errors" do
+    diagnostic = %{
+      rule: "typescript/TS2322",
+      severity: :warning,
+      file: "typed.ts",
+      message: "Type number is not assignable to type string."
+    }
+
+    assert %{severity: :error} =
+             Volt.JS.Check.promote_type_check_diagnostic(diagnostic, type_check: true)
+  end
+
+  test "type-aware check keeps Oxlint-style rules and retries without unsupported tsgolint rules" do
+    File.write!(Path.join(@tmp_dir, "typed.ts"), "export const value = 1\n")
+    tsgolint = fake_tsgolint_unknown_retry!(@tmp_dir)
+
+    Application.put_env(:volt, :lint,
+      tsgolint: tsgolint,
+      rules: %{
+        "correctness" => :deny,
+        "suspicious" => :deny,
+        "no-console" => :warn,
+        "typescript/consistent-type-imports" => :deny,
+        "typescript/no-floating-promises" => :warn
+      }
+    )
+
+    capture_io(fn ->
+      Mix.Tasks.Volt.Js.Check.run(["--type-aware"])
+    end)
+
+    payload = @tmp_dir |> Path.join("payload.json") |> File.read!() |> Jason.decode!()
+    assert [%{"rules" => rules}] = payload["configs"]
+    assert Enum.any?(rules, &(&1["name"] == "no-floating-promises"))
+
+    refute Enum.any?(
+             rules,
+             &(&1["name"] in ["correctness", "suspicious", "consistent-type-imports"])
+           )
+  end
+
+  test "type-aware check submits framework single-file component scripts as virtual files" do
+    File.write!(Path.join(@tmp_dir, "app.ts"), "import './Component.vue'\n")
+
+    File.write!(
+      Path.join(@tmp_dir, "Component.vue"),
+      "<script setup lang=\"ts\">const vueValue: string = 'ok'</script>\n"
+    )
+
+    File.write!(
+      Path.join(@tmp_dir, "Widget.svelte"),
+      "<script lang=\"ts\">const svelteValue: string = 'ok'</script>\n"
+    )
+
+    tsgolint = fake_tsgolint_capture!(@tmp_dir)
+
+    Application.put_env(:volt, :sources, ["**/*.{js,ts,jsx,tsx,vue,svelte}"])
+
+    Application.put_env(:volt, :lint,
+      tsgolint: tsgolint,
+      rules: %{"typescript/no-floating-promises" => :deny}
+    )
+
+    capture_io(fn ->
+      Mix.Tasks.Volt.Js.Check.run(["--type-aware"])
+    end)
+
+    payload = @tmp_dir |> Path.join("payload.json") |> File.read!() |> Jason.decode!()
+    assert [%{"file_paths" => file_paths}] = payload["configs"]
+    basenames = Enum.map(file_paths, &Path.basename/1)
+
+    assert "app.ts" in basenames
+    assert "Component.vue.script0.ts" in basenames
+    assert "Widget.svelte.script0.ts" in basenames
+
+    overrides = payload["source_overrides"]
+    assert overrides[Path.expand(Path.join(@tmp_dir, "Component.vue.script0.ts"))] =~ "vueValue"
+
+    assert overrides[Path.expand(Path.join(@tmp_dir, "Widget.svelte.script0.ts"))] =~
+             "svelteValue"
+  end
+
+  test "type-aware check declares single-file components for their importers" do
+    File.write!(Path.join(@tmp_dir, "app.ts"), "import './Button.vue'\n")
+
+    File.write!(Path.join(@tmp_dir, "Button.vue"), """
+    <script setup lang="ts">
+    defineProps<{ variant?: 'primary' | 'ghost' }>()
+    </script>
+    <template><button /></template>
+    """)
+
+    File.write!(Path.join(@tmp_dir, "Legacy.vue"), "<template><p /></template>\n")
+    File.write!(Path.join(@tmp_dir, "Legacy.vue.d.ts"), "export default 1\n")
+
+    tsgolint = fake_tsgolint_capture!(@tmp_dir)
+    Application.put_env(:volt, :sources, ["**/*.{ts,vue}"])
+    Application.put_env(:volt, :lint, tsgolint: tsgolint, rules: %{})
+
+    capture_io(fn -> Mix.Tasks.Volt.Js.Check.run(["--type-aware", "--type-check"]) end)
+
+    payload = @tmp_dir |> Path.join("payload.json") |> File.read!() |> Jason.decode!()
+    [%{"file_paths" => file_paths}] = payload["configs"]
+    overrides = payload["source_overrides"]
+
+    # The declaration is resolved from the import, not checked as a file.
+    declaration = overrides[Path.expand(Path.join(@tmp_dir, "Button.vue.d.ts"))]
+    assert declaration =~ "export type Props = { variant?: 'primary' | 'ghost' }"
+    assert declaration =~ "export default"
+    refute "Button.vue.d.ts" in Enum.map(file_paths, &Path.basename/1)
+
+    # A declaration the project wrote itself is left to it.
+    refute Map.has_key?(overrides, Path.expand(Path.join(@tmp_dir, "Legacy.vue.d.ts")))
+  end
+
+  @tsgolint Path.expand("node_modules/.bin/tsgolint")
+
+  # Runs the real tsgolint, which CI and `npm ci` install.
+  @tag skip: not File.exists?(@tsgolint)
+  test "imports of single-file components are typed by their props without a shim" do
+    write = fn path, content ->
+      path = Path.join(@tmp_dir, path)
+      File.mkdir_p!(Path.dirname(path))
+      File.write!(path, content)
+    end
+
+    write.("tsconfig.json", """
+    {
+      "compilerOptions": { "strict": true, "noEmit": true, "moduleResolution": "Bundler" },
+      "include": ["assets/js/**/*.ts"]
+    }
+    """)
+
+    write.("assets/js/ui/Button.vue", """
+    <script setup lang="ts">
+    defineProps<{ variant?: 'primary' | 'ghost' }>()
+    </script>
+    <template><button /></template>
+    """)
+
+    write.("assets/js/app.ts", """
+    import Button from "./ui/Button.vue"
+    type Variant = InstanceType<typeof Button>["$props"]["variant"]
+    export const ghost: Variant = "ghost"
+    export const huge: Variant = "huge"
+    """)
+
+    Application.put_env(:volt, :sources, ["assets/js/**/*.{ts,vue}"])
+    Application.put_env(:volt, :lint, tsgolint: @tsgolint, rules: %{})
+
+    output =
+      capture_io(:stderr, fn ->
+        catch_exit(Mix.Tasks.Volt.Js.Check.run(["--type-aware", "--type-check"]))
+      end)
+
+    assert output =~ "app.ts:4"
+    assert output =~ "TS2322"
+    refute output =~ "app.ts:3"
+    refute output =~ "Cannot find module"
+  end
+
+  # Runs the real tsgolint, which CI and `npm ci` install.
+  @tag skip: not File.exists?(@tsgolint)
+  test "component scripts are type-checked with the project's tsconfig" do
+    write = fn path, content ->
+      path = Path.join(@tmp_dir, path)
+      File.mkdir_p!(Path.dirname(path))
+      File.write!(path, content)
+    end
+
+    write.("tsconfig.json", """
+    {
+      "compilerOptions": {
+        "strict": true,
+        "noEmit": true,
+        "moduleResolution": "Bundler",
+        "paths": { "@/*": ["./assets/js/*"] }
+      },
+      "include": ["assets/js/**/*.ts", "lib/**/*.ts"]
+    }
+    """)
+
+    write.("assets/js/ui/variants.ts", "export const button = (n: number) => n\n")
+    write.("assets/js/ui/Button.vue", "<template><button /></template>\n")
+
+    write.("assets/js/vue.d.ts", """
+    declare module "*.vue" {
+      const component: unknown
+      export default component
+    }
+    """)
+
+    write.("lib/app_web/Tally.vue", """
+    <script setup lang="ts">
+    import Button from "@/ui/Button.vue"
+    import { button } from "@/ui/variants"
+    const probe: (n: number) => void = (n: string) => n
+    console.log(Button, button, probe)
+    </script>
+    <template><p /></template>
+    """)
+
+    Application.put_env(:volt, :sources, ["lib/**/*.vue"])
+    Application.put_env(:volt, :lint, tsgolint: @tsgolint, rules: %{})
+
+    output =
+      capture_io(:stderr, fn ->
+        catch_exit(Mix.Tasks.Volt.Js.Check.run(["--type-aware", "--type-check"]))
+      end)
+
+    # The script is type-checked, and with the project's options: the path
+    # alias and the `*.vue` declaration resolve.
+    assert output =~ "TS2322"
+    refute output =~ "TS2307"
+    refute output =~ "Cannot find module"
+  end
+
+  test "type-aware overrides batch by effective rules and use original SFC paths" do
+    files = Enum.map(["app.ts", "Component.vue", "Widget.svelte"], &Path.join(@tmp_dir, &1))
+    [app, vue, svelte] = files
+    File.write!(app, "export const value = 1;\n")
+    File.write!(vue, "<script setup lang=\"ts\">const vueValue = 1</script>\n")
+    File.write!(svelte, "<script lang=\"ts\">const svelteValue = 1</script>\n")
+    payload_path = Path.join(@tmp_dir, "batches.jsonl")
+
+    tsgolint =
+      fake_executable!(@tmp_dir, "tsgolint-batches", """
+      input = IO.binread(:stdio, :eof)
+      File.write!(#{inspect(payload_path)}, [input, "\\n"], [:append])
+      payload = JSON.decode!(input)
+      for config <- payload["configs"], file <- config["file_paths"] do
+        json = JSON.encode!(%{kind: 0, rule: "no-floating-promises", message: %{id: "floatingPromise", description: "batch diagnostic"}, file_path: file, range: %{pos: 0, end: 1}})
+        IO.binwrite(<<byte_size(json)::32-little, 1, json::binary>>)
+      end
+      """)
+
+    Application.put_env(:volt, :lint,
+      root: @tmp_dir,
+      tsgolint: tsgolint,
+      rules: %{"correctness" => :deny, "typescript/no-floating-promises" => :deny},
+      overrides: [
+        %{files: ["**/*.{vue,svelte}"], rules: %{"typescript/no-floating-promises" => :warn}},
+        %{files: ["**/*.script0.ts"], rules: %{"typescript/no-floating-promises" => :allow}}
+      ]
+    )
+
+    diagnostics = Volt.JS.Check.lint(files, type_aware: true)
+
+    assert Enum.sort(Enum.map(diagnostics, & &1.file)) ==
+             Enum.sort([Path.expand(app), vue, svelte])
+
+    batches =
+      payload_path |> File.read!() |> String.split("\n", trim: true) |> Enum.map(&Jason.decode!/1)
+
+    assert length(batches) == 2
+
+    configs = Enum.flat_map(batches, & &1["configs"])
+    assert Enum.sort(Enum.map(configs, &length(&1["file_paths"]))) == [1, 2]
+
+    names = configs |> Enum.flat_map(& &1["rules"]) |> Enum.map(& &1["name"])
+    assert "no-floating-promises" in names
+    refute "correctness" in names
+
+    assert Enum.find(diagnostics, &(&1.file == Path.expand(app))).severity == :error
+    assert Enum.find(diagnostics, &(&1.file == vue)).severity == :warning
+    assert Enum.find(diagnostics, &(&1.file == svelte)).severity == :warning
+
+    for batch <- batches do
+      assert batch["source_overrides"][Path.expand(vue <> ".script0.ts")] =~ "vueValue"
+      assert batch["source_overrides"][Path.expand(svelte <> ".script0.ts")] =~ "svelteValue"
+    end
+  end
+
+  defp fake_tsgolint!(dir) do
+    fake_executable!(dir, "tsgolint", """
+    json = ~s({"kind":0,"rule":"no-floating-promises","message":{"id":"floatingPromise","description":"floating promise"},"file_path":"typed.ts","range":{"pos":0,"end":5}})
+    IO.binwrite(<<byte_size(json)::32-little, 1, json::binary>>)
+    """)
+  end
+
+  defp fake_tsgolint_capture!(dir) do
+    payload_path = Path.join(dir, "payload.json")
+
+    fake_executable!(dir, "tsgolint-capture", """
+    File.write!(#{inspect(payload_path)}, IO.binread(:stdio, :eof))
+    """)
+  end
+
+  defp fake_tsgolint_unknown_retry!(dir) do
+    payload_path = Path.join(dir, "payload.json")
+    input_path = Path.join(dir, "payload-attempt.json")
+
+    fake_executable!(dir, "tsgolint-unknown-retry", """
+    payload = IO.binread(:stdio, :eof)
+    File.write!(#{inspect(input_path)}, payload)
+
+    if String.contains?(payload, "consistent-type-imports") do
+      IO.puts(:stderr, "panic: unknown rule: consistent-type-imports [recovered, repanicked]")
+      System.halt(2)
+    end
+
+    File.write!(#{inspect(payload_path)}, payload)
+    """)
+  end
+
+  defp fake_executable!(dir, name, code) do
+    script = Path.expand("#{name}.exs", dir)
+    File.write!(script, ":io.setopts(:standard_io, encoding: :latin1)\n" <> code)
+
+    case :os.type() do
+      {:win32, _name} ->
+        path = Path.expand("#{name}.cmd", dir)
+        File.write!(path, "@echo off\r\nelixir.bat \"#{script}\"\r\n")
+        path
+
+      _unix ->
+        path = Path.expand(name, dir)
+        File.write!(path, "#!/bin/sh\nexec elixir \"#{script}\"\n")
+        File.chmod!(path, 0o755)
+        path
+    end
+  end
+end
diff --git a/test/mix/tasks/volt/lint_test.exs b/test/mix/tasks/volt/lint_test.exs
new file mode 100644
index 0000000..4682aa3
--- /dev/null
+++ b/test/mix/tasks/volt/lint_test.exs
@@ -0,0 +1,247 @@
+defmodule Mix.Tasks.Volt.LintTest do
+  use ExUnit.Case, async: false
+
+  import ExUnit.CaptureIO
+
+  @tmp_dir "tmp/lint_test_#{:erlang.unique_integer([:positive])}"
+
+  setup do
+    File.mkdir_p!(@tmp_dir)
+    on_exit(fn -> File.rm_rf!(@tmp_dir) end)
+    original_root = Application.get_env(:volt, :root)
+    original_lint = Application.get_env(:volt, :lint)
+    Application.put_env(:volt, :root, @tmp_dir)
+
+    on_exit(fn ->
+      if original_root,
+        do: Application.put_env(:volt, :root, original_root),
+        else: Application.delete_env(:volt, :root)
+
+      if original_lint,
+        do: Application.put_env(:volt, :lint, original_lint),
+        else: Application.delete_env(:volt, :lint)
+    end)
+
+    :ok
+  end
+
+  test "reports no issues for clean code" do
+    File.write!(Path.join(@tmp_dir, "clean.ts"), "export const x = 1;\n")
+    Application.put_env(:volt, :lint, plugins: ["typescript"])
+
+    output = capture_io(fn -> Mix.Tasks.Volt.Lint.run([]) end)
+    assert output =~ "No issues found"
+  end
+
+  test "detects eqeqeq violation" do
+    File.write!(Path.join(@tmp_dir, "bad.js"), "export const y = x == 1;\n")
+    Application.put_env(:volt, :lint, rules: %{"eqeqeq" => :deny})
+
+    output =
+      capture_io(fn ->
+        catch_exit(Mix.Tasks.Volt.Lint.run([]))
+      end)
+
+    assert output =~ "eqeqeq"
+    assert output =~ "error"
+  end
+
+  test "detects typescript rule" do
+    File.write!(Path.join(@tmp_dir, "typed.ts"), "export function foo(x: any) { return x; }\n")
+
+    Application.put_env(:volt, :lint,
+      plugins: ["typescript"],
+      rules: %{"typescript/no-explicit-any" => :warn}
+    )
+
+    output = capture_io(fn -> Mix.Tasks.Volt.Lint.run([]) end)
+    assert output =~ "no-explicit-any"
+  end
+
+  test "CLI --plugin flag overrides config" do
+    File.write!(Path.join(@tmp_dir, "typed.ts"), "export function foo(x: any) { return x; }\n")
+
+    Application.put_env(:volt, :lint,
+      plugins: [],
+      rules: %{"typescript/no-explicit-any" => :warn}
+    )
+
+    output = capture_io(fn -> Mix.Tasks.Volt.Lint.run(["--plugin", "typescript"]) end)
+    assert output =~ "no-explicit-any"
+  end
+
+  test "generated filenames can be exempted without disabling filename-case elsewhere" do
+    File.mkdir_p!(Path.join(@tmp_dir, "colocated/DemoWeb"))
+    generated = Path.join(@tmp_dir, "colocated/DemoWeb/BadName.js")
+    authored = Path.join(@tmp_dir, "BadName.js")
+    for file <- [generated, authored], do: File.write!(file, "export const value = 1;\n")
+
+    Application.put_env(:volt, :lint,
+      plugins: ["unicorn"],
+      rules: %{"unicorn/filename-case" => :deny},
+      overrides: [%{files: ["colocated/**/*.js"], rules: %{"unicorn/filename-case" => :allow}}]
+    )
+
+    assert [%{file: ^authored, rule: rule}] = Volt.JS.Check.lint([generated, authored])
+    assert rule =~ "filename-case"
+
+    output =
+      capture_io(fn -> assert catch_exit(Mix.Tasks.Volt.Lint.run([])) == {:shutdown, 1} end)
+
+    refute output =~ "colocated/DemoWeb"
+    assert output =~ "BadName.js"
+    assert output =~ "filename-case"
+  end
+
+  test "CLI plugins still enable rules introduced by an override" do
+    File.write!(Path.join(@tmp_dir, "typed.ts"), "export function foo(x: any) { return x; }\n")
+
+    Application.put_env(:volt, :lint,
+      plugins: [],
+      overrides: [%{files: ["typed.ts"], rules: %{"typescript/no-explicit-any" => :warn}}]
+    )
+
+    output = capture_io(fn -> Mix.Tasks.Volt.Lint.run(["--plugin", "typescript"]) end)
+    assert output =~ "no-explicit-any"
+  end
+
+  test "applies scoped rules, environments and globals in both lint commands" do
+    File.mkdir_p!(Path.join(@tmp_dir, "scripts"))
+    script = Path.join(@tmp_dir, "scripts/build.js")
+    browser = Path.join(@tmp_dir, "browser.js")
+    File.write!(script, "process.exitCode = externalValue;\nexport const value = null;\n")
+    File.write!(browser, "document.title = externalValue;\nexport const value = null;\n")
+
+    Application.put_env(:volt, :lint,
+      root: @tmp_dir,
+      plugins: ["unicorn"],
+      env: ["browser"],
+      rules: %{"no-undef" => :deny, "unicorn/no-null" => :deny},
+      overrides: [
+        %{
+          files: ["scripts/**/*.js"],
+          env: %{"browser" => false, "node" => true},
+          globals: %{"externalValue" => :readonly},
+          rules: %{"unicorn/no-null" => :allow}
+        }
+      ]
+    )
+
+    diagnostics = Volt.JS.Check.lint([script, browser])
+    refute Enum.any?(diagnostics, &(&1.file == script))
+    assert Enum.any?(diagnostics, &(&1.file == browser and &1.rule =~ "no-null"))
+    assert Enum.any?(diagnostics, &(&1.file == browser and &1.message =~ "externalValue"))
+
+    output =
+      capture_io(fn -> assert catch_exit(Mix.Tasks.Volt.Lint.run([])) == {:shutdown, 1} end)
+
+    refute output =~ "scripts/build.js"
+    assert output =~ "browser.js"
+    assert output =~ "no-null"
+    assert output =~ "externalValue"
+
+    for file <- [script, browser] do
+      {:ok, formatted} = OXC.Format.run(File.read!(file), file, Volt.JS.Format.load_config())
+      File.write!(file, formatted)
+    end
+
+    check_output =
+      capture_io(:stderr, fn ->
+        capture_io(fn -> assert catch_exit(Mix.Tasks.Volt.Js.Check.run([])) == {:shutdown, 1} end)
+      end)
+
+    refute check_output =~ "scripts/build.js"
+    assert check_output =~ "browser.js"
+    assert check_output =~ "no-null"
+    assert check_output =~ "externalValue"
+  end
+
+  test "overrides can disable inherited environments and globals" do
+    file = Path.join(@tmp_dir, "server.js")
+    File.write!(file, "document.title = sharedGlobal;\nprocess.exitCode = 0;\n")
+
+    Application.put_env(:volt, :lint,
+      env: ["browser"],
+      globals: %{"sharedGlobal" => :readonly},
+      rules: %{"no-undef" => :deny},
+      overrides: [
+        %{
+          files: ["server.js"],
+          env: %{"browser" => false, "node" => true},
+          globals: %{"sharedGlobal" => :off}
+        }
+      ]
+    )
+
+    diagnostics = Volt.JS.Check.lint([file])
+    assert length(diagnostics) == 2
+    assert Enum.any?(diagnostics, &(&1.message =~ "document"))
+    assert Enum.any?(diagnostics, &(&1.message =~ "sharedGlobal"))
+    refute Enum.any?(diagnostics, &(&1.message =~ "process"))
+
+    output =
+      capture_io(fn -> assert catch_exit(Mix.Tasks.Volt.Lint.run([])) == {:shutdown, 1} end)
+
+    assert output =~ "document"
+    assert output =~ "sharedGlobal"
+    refute output =~ "process"
+  end
+
+  test "skips node_modules" do
+    File.mkdir_p!(Path.join(@tmp_dir, "node_modules/pkg"))
+    File.write!(Path.join([@tmp_dir, "node_modules", "pkg", "bad.js"]), "debugger;\n")
+    Application.put_env(:volt, :lint, rules: %{"no-debugger" => :deny})
+
+    output = capture_io(fn -> Mix.Tasks.Volt.Lint.run([]) end)
+    assert output =~ "No lintable files"
+  end
+
+  test "reports correct file location" do
+    File.write!(Path.join(@tmp_dir, "loc.js"), "const a = 1;\nexport const b = x == y;\n")
+    Application.put_env(:volt, :lint, rules: %{"eqeqeq" => :deny})
+
+    output =
+      capture_io(fn ->
+        catch_exit(Mix.Tasks.Volt.Lint.run([]))
+      end)
+
+    assert output =~ "loc.js:2:"
+  end
+
+  test "custom rules via config" do
+    defmodule TestNoDebugger do
+      @behaviour OXC.Lint.Rule
+
+      @impl true
+      def meta,
+        do: %{
+          name: "test/no-debugger-custom",
+          description: "custom",
+          category: :correctness,
+          fixable: false
+        }
+
+      @impl true
+      def run(ast, _ctx) do
+        OXC.collect(ast, fn
+          %{type: :debugger_statement, start: start, end: stop} ->
+            {:keep, %{start: start, end: stop, message: "custom debugger ban"}}
+
+          _ ->
+            :skip
+        end)
+      end
+    end
+
+    File.write!(Path.join(@tmp_dir, "dbg.js"), "export function f() { debugger; }\n")
+    Application.put_env(:volt, :lint, custom_rules: [{TestNoDebugger, :deny}])
+
+    output =
+      capture_io(fn ->
+        catch_exit(Mix.Tasks.Volt.Lint.run([]))
+      end)
+
+    assert output =~ "custom debugger ban"
+    assert output =~ "test/no-debugger-custom"
+  end
+end
diff --git a/test/support/volt/builder_case.exs b/test/support/volt/builder_case.ex
similarity index 90%
rename from test/support/volt/builder_case.exs
rename to test/support/volt/builder_case.ex
index 1c16aa9..00356d0 100644
--- a/test/support/volt/builder_case.exs
+++ b/test/support/volt/builder_case.ex
@@ -74,6 +74,8 @@ defmodule Volt.TestSupport.BuilderCase do
     def resolve("virtual:site/entry-a", _), do: {:ok, "virtual:site/entry-a"}
     def resolve("virtual:site/entry-b", _), do: {:ok, "virtual:site/entry-b"}
     def resolve("virtual:site/style-entry", _), do: {:ok, "virtual:site/style-entry"}
+    def resolve("virtual:collision/entry:a", _), do: {:ok, "virtual:collision/entry:a"}
+    def resolve("virtual:collision/entry|a", _), do: {:ok, "virtual:collision/entry|a"}
     def resolve("virtual:plain", _), do: {:ok, "virtual:plain"}
 
     def resolve("./style.css", "virtual:site/style-entry"),
@@ -91,6 +93,8 @@ defmodule Volt.TestSupport.BuilderCase do
     def load("virtual:site/style-entry"),
       do: {:ok, "import './style.css'; console.log('with css');"}
 
+    def load("virtual:collision/entry:a"), do: {:ok, "console.log('colon entry');"}
+    def load("virtual:collision/entry|a"), do: {:ok, "console.log('pipe entry');"}
     def load("virtual:plain"), do: {:ok, "export default 123;"}
 
     def load(_), do: nil
@@ -102,7 +106,7 @@ defmodule Volt.TestSupport.BuilderCase do
 
       alias Volt.TestSupport.BuilderCase.{EmbeddedBoxPlugin, JSLoaderPlugin, VirtualModPlugin}
 
-      @fixture_dir Path.join(System.tmp_dir!(), "volt-builder-test")
+      @fixture_dir Path.expand("volt-builder-test", System.tmp_dir!())
       @outdir Path.join(@fixture_dir, "dist")
 
       setup do
diff --git a/test/support/volt/dev_server_case.exs b/test/support/volt/dev_server_case.ex
similarity index 93%
rename from test/support/volt/dev_server_case.exs
rename to test/support/volt/dev_server_case.ex
index 005e0af..3647926 100644
--- a/test/support/volt/dev_server_case.exs
+++ b/test/support/volt/dev_server_case.ex
@@ -83,7 +83,7 @@ defmodule Volt.TestSupport.DevServerCase do
 
       alias Volt.TestSupport.DevServerCase.{EmbeddedBoxPlugin, VirtualPlugin}
 
-      @fixture_dir Path.join(System.tmp_dir!(), "volt-dev-server-test")
+      @fixture_dir Path.expand("volt-dev-server-test", System.tmp_dir!())
 
       setup do
         File.mkdir_p!(Path.join(@fixture_dir, "src"))
@@ -98,8 +98,13 @@ defmodule Volt.TestSupport.DevServerCase do
         Volt.Cache.clear()
         Volt.HMR.StyleGraph.clear()
         Volt.HMR.ModuleGraph.clear()
+        Volt.HMR.Errors.clear_session(:default)
+
+        on_exit(fn ->
+          Volt.HMR.Errors.clear_session(:default)
+          File.rm_rf!(@fixture_dir)
+        end)
 
-        on_exit(fn -> File.rm_rf!(@fixture_dir) end)
         :ok
       end
 
diff --git a/test/test_helper.exs b/test/test_helper.exs
index 94b4500..701fa85 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -1,7 +1,3 @@
-Path.wildcard(Path.expand("support/**/*.exs", __DIR__))
-|> Enum.sort()
-|> Enum.each(&Code.require_file/1)
-
 ExUnit.start(exclude: [:integration])
 
 Volt.Test.ExUnit.install(root: "test/volt/test/fixtures", include: ["core_api.test.ts"])
diff --git a/test/volt/application_test.exs b/test/volt/application_test.exs
new file mode 100644
index 0000000..e99e7cf
--- /dev/null
+++ b/test/volt/application_test.exs
@@ -0,0 +1,22 @@
+defmodule Volt.ApplicationTest do
+  use ExUnit.Case, async: true
+
+  test "Tailwind processes start before watchers, so they stop after them" do
+    # `Supervisor.which_children/1` lists children in reverse start order.
+    started =
+      Volt.Supervisor
+      |> Supervisor.which_children()
+      |> Enum.map(fn {id, _pid, _type, _modules} -> id end)
+      |> Enum.reverse()
+
+    position = fn id -> Enum.find_index(started, &(&1 == id)) end
+
+    for tailwind <- [
+          Volt.Tailwind.Registry,
+          Volt.Tailwind.WorkerSupervisor,
+          Volt.Tailwind.Runtime
+        ] do
+      assert position.(tailwind) < position.(Volt.Dev.WatcherSupervisor)
+    end
+  end
+end
diff --git a/test/volt/assets_test.exs b/test/volt/assets_test.exs
index 78e3276..b4f87ae 100644
--- a/test/volt/assets_test.exs
+++ b/test/volt/assets_test.exs
@@ -1,7 +1,7 @@
 defmodule Volt.AssetsTest do
   use ExUnit.Case, async: true
 
-  @fixture_dir Path.join(System.tmp_dir!(), "volt-assets-test")
+  @fixture_dir Path.expand("volt-assets-test", System.tmp_dir!())
 
   setup do
     File.mkdir_p!(@fixture_dir)
@@ -9,6 +9,24 @@ defmodule Volt.AssetsTest do
     :ok
   end
 
+  @tag :tmp_dir
+  test "prepares a URL module without writing its referenced asset", %{tmp_dir: root} do
+    source = Path.join(root, "logo.svg")
+    outdir = Path.join(root, "output")
+    File.write!(source, "<svg/>")
+    opts = [url: true, root: root, outdir: outdir, prefix: "https://cdn.example/assets"]
+
+    assert {:ok, prepared} = Volt.Assets.prepare_js_module(source, opts)
+    assert [%Volt.Builder.Artifact{file: file, content: "<svg/>"}] = prepared.artifacts
+    assert [%Volt.Builder.Asset{src: "logo.svg", file: ^file}] = prepared.assets
+    assert prepared.code =~ "https://cdn.example/assets/#{file}"
+    refute File.exists?(outdir)
+
+    assert {:ok, emitted} = Volt.Assets.emit_js_module(source, opts)
+    assert emitted == Map.take(prepared, [:code, :assets])
+    assert File.read!(Path.join(outdir, file)) == "<svg/>"
+  end
+
   describe "asset?/1" do
     test "recognizes image types" do
       assert Volt.Assets.asset?("photo.jpg")
diff --git a/test/volt/build/layout_test.exs b/test/volt/build/layout_test.exs
new file mode 100644
index 0000000..165c494
--- /dev/null
+++ b/test/volt/build/layout_test.exs
@@ -0,0 +1,17 @@
+defmodule Volt.Build.LayoutTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.Build.Layout
+
+  test "asset directory prefixes both layout presets" do
+    assert Layout.new(:flat, "assets") == %Layout{scripts: "assets", styles: "assets"}
+    assert Layout.new(:split, "assets") == %Layout{scripts: "assets/js", styles: "assets/css"}
+    assert Layout.new(:flat) == %Layout{scripts: "", styles: ""}
+  end
+
+  test "asset directory cannot escape the publication root" do
+    for path <- ["/assets", "../assets", "a/../assets", "C:\\assets"] do
+      assert_raise ArgumentError, fn -> Layout.new(:flat, path) end
+    end
+  end
+end
diff --git a/test/volt/build_test.exs b/test/volt/build_test.exs
new file mode 100644
index 0000000..bb29470
--- /dev/null
+++ b/test/volt/build_test.exs
@@ -0,0 +1,366 @@
+defmodule Volt.BuildTest do
+  use ExUnit.Case, async: false
+
+  @moduletag :tmp_dir
+
+  setup %{tmp_dir: tmp} do
+    root = Path.join(tmp, "assets")
+    outdir = Path.join(tmp, "dist/assets")
+    File.mkdir_p!(root)
+    File.write!(Path.join(root, "app.ts"), "document.body.dataset.ready = 'true'")
+    File.write!(Path.join(root, "styles.css"), ~S|@import "tailwindcss" source(none);|)
+    File.write!(Path.join(root, "page.html"), ~S|<main class="grid gap-4"></main>|)
+
+    {:ok, root: root, outdir: outdir}
+  end
+
+  test "shared output manifest includes only emitted chunk identities", %{
+    root: root,
+    outdir: outdir
+  } do
+    File.write!(
+      Path.join(root, "one.ts"),
+      "import {value} from 'external-lib'; console.log(value); export const load = () => import('external-lazy')"
+    )
+
+    File.write!(
+      Path.join(root, "two.ts"),
+      "import {value} from 'external-lib'; console.log(value)"
+    )
+
+    assert {:ok, result} =
+             Volt.build(
+               entry: [Path.join(root, "one.ts"), Path.join(root, "two.ts")],
+               root: root,
+               outdir: outdir,
+               tailwind: [],
+               format: :esm,
+               minify: false,
+               external: ["external-lib", "external-lazy"]
+             )
+
+    for {_key, entry} <- result.manifest do
+      for reference <- entry.imports ++ entry.dynamicImports do
+        assert Map.has_key?(result.manifest, reference)
+      end
+
+      refute "external-lib" in entry.imports
+      refute "external-lazy" in entry.dynamicImports
+    end
+  end
+
+  test "nested assets keep public files and manifest at the publication root", %{
+    root: root,
+    outdir: outdir
+  } do
+    public = Path.join(root, "public")
+    File.mkdir_p!(public)
+    File.write!(Path.join(public, "robots.txt"), "public")
+
+    for layout <- [:flat, :split] do
+      destination = Path.join(outdir, Atom.to_string(layout))
+
+      assert {:ok, result} =
+               Volt.build(
+                 entry: Path.join(root, "app.ts"),
+                 root: root,
+                 outdir: destination,
+                 assets_dir: "assets",
+                 output_layout: layout,
+                 public_dir: public,
+                 tailwind: [],
+                 hash: false
+               )
+
+      suffix = if layout == :flat, do: "assets/app.js", else: "assets/js/app.js"
+      assert result.manifest["app.js"].file == suffix
+      assert File.regular?(Path.join(destination, suffix))
+      assert File.regular?(Path.join(destination, "manifest.json"))
+      assert File.read!(Path.join(destination, "robots.txt")) == "public"
+    end
+  end
+
+  test "public destination is independent of asset layout", %{root: root, outdir: outdir} do
+    public = Path.join(root, "public")
+    File.mkdir_p!(public)
+    File.write!(Path.join(public, "robots.txt"), "public")
+
+    for layout <- [:flat, :split] do
+      destination = Path.join(outdir, Atom.to_string(layout))
+
+      assert {:ok, _} =
+               Volt.build(
+                 entry: Path.join(root, "app.ts"),
+                 root: root,
+                 outdir: destination,
+                 output_layout: layout,
+                 public_dir: public,
+                 tailwind: []
+               )
+
+      assert File.read!(Path.join(destination, "robots.txt")) == "public"
+    end
+  end
+
+  test "returns every standalone stylesheet", %{root: root, outdir: outdir} do
+    entries =
+      for name <- ["first", "second"] do
+        path = Path.join(root, "#{name}.css")
+        File.write!(path, ".#{name} { color: red }")
+        path
+      end
+
+    assert {:ok, result} =
+             Volt.build(entry: entries, root: root, outdir: outdir, tailwind: [], hash: false)
+
+    assert Enum.map(result.styles, &Path.basename(&1.path)) == ["first.css", "second.css"]
+    assert result.assets.styles == result.styles
+    assert Enum.all?(result.styles, &File.regular?(&1.path))
+  end
+
+  test "flat output deduplicates assets shared by Tailwind and JavaScript", %{
+    root: root,
+    outdir: outdir
+  } do
+    File.write!(Path.join(root, "logo.svg"), "<svg/>")
+    File.write!(Path.join(root, "app.ts"), "import logo from './logo.svg?url'; console.log(logo)")
+
+    File.write!(
+      Path.join(root, "styles.css"),
+      "@import 'tailwindcss' source(none); .logo { background: url('./logo.svg') }"
+    )
+
+    assert {:ok, result} =
+             Volt.build(
+               entry: Path.join(root, "app.ts"),
+               root: root,
+               outdir: outdir,
+               output_layout: :flat,
+               hash: false,
+               minify: false,
+               tailwind: [css: Path.join(root, "styles.css")]
+             )
+
+    assert %Volt.Builder.ManifestEntry{file: file} = result.manifest["logo.svg"]
+    assert File.read!(Path.join(outdir, file)) == "<svg/>"
+    assert [_] = Path.wildcard(Path.join(outdir, "logo-*.svg"))
+  end
+
+  test "public files cannot overwrite compiled output", %{root: root, outdir: outdir} do
+    public = Path.join(root, "public")
+    File.mkdir_p!(Path.join(public, "js"))
+    File.write!(Path.join(public, "js/app.js"), "public collision")
+
+    opts = [
+      entry: Path.join(root, "app.ts"),
+      root: root,
+      outdir: outdir,
+      hash: false,
+      minify: false,
+      sourcemap: false,
+      tailwind: []
+    ]
+
+    assert {:ok, _} = Volt.build(opts)
+    previous = File.read!(Path.join(outdir, "js/app.js"))
+
+    assert {:error, {:output_collision, "js/app.js"}} =
+             Volt.build(Keyword.put(opts, :public_dir, public))
+
+    assert File.read!(Path.join(outdir, "js/app.js")) == previous
+  end
+
+  test "later entry failure leaves the previous build untouched", %{root: root, outdir: outdir} do
+    opts = [
+      root: root,
+      outdir: outdir,
+      hash: false,
+      minify: false,
+      sourcemap: false,
+      tailwind: []
+    ]
+
+    entry = Path.join(root, "app.ts")
+    assert {:ok, _} = Volt.build([entry: entry] ++ opts)
+
+    snapshot = fn ->
+      Path.wildcard(Path.join(outdir, "**/*"))
+      |> Enum.filter(&File.regular?/1)
+      |> Map.new(&{&1, File.read!(&1)})
+    end
+
+    before = snapshot.()
+    File.write!(entry, "console.log('replacement')")
+    bad = Path.join(root, "broken.ts")
+    File.write!(bad, "export const = ;")
+    assert {:error, _} = Volt.build([entry: [entry, bad]] ++ opts)
+    assert snapshot.() == before
+  end
+
+  test "flat Tailwind collision preserves previous output", %{root: root, outdir: outdir} do
+    plain = Path.join(root, "plain.css")
+    File.write!(plain, "body { color: red }")
+
+    opts = [
+      entry: plain,
+      root: root,
+      outdir: outdir,
+      output_layout: :flat,
+      hash: false,
+      tailwind: []
+    ]
+
+    assert {:ok, _} = Volt.build(opts)
+    before = File.read!(Path.join(outdir, "plain.css"))
+    manifest = File.read!(Path.join(outdir, "manifest.json"))
+
+    assert {:error, {:output_collision, "plain.css"}} =
+             Volt.build(
+               Keyword.put(opts, :tailwind, css: Path.join(root, "styles.css"), name: "plain")
+             )
+
+    assert File.read!(Path.join(outdir, "plain.css")) == before
+    assert File.read!(Path.join(outdir, "manifest.json")) == manifest
+  end
+
+  test "builds scripts and Tailwind into one manifest", %{root: root, outdir: outdir} do
+    assert {:ok, result} =
+             Volt.build(
+               entry: Path.join(root, "app.ts"),
+               root: root,
+               outdir: outdir,
+               hash: false,
+               minify: false,
+               sourcemap: false,
+               tailwind: [
+                 css: Path.join(root, "styles.css"),
+                 name: "site",
+                 sources: [%{base: root, pattern: "**/*.html"}]
+               ]
+             )
+
+    assert File.regular?(Path.join(outdir, "js/app.js"))
+    assert File.regular?(Path.join(outdir, "css/site.css"))
+    assert File.read!(Path.join(outdir, "css/site.css")) =~ ".grid"
+
+    assert [%Volt.Builder.OutputFile{path: style_path}] = result.styles
+    assert style_path == Path.join(outdir, "css/site.css")
+    assert result.assets.manifest["app.js"].file == "js/app.js"
+    assert result.manifest["site.css"].file == "css/site.css"
+
+    assert Enum.all?(result.manifest, fn {_key, entry} ->
+             match?(%Volt.Builder.ManifestEntry{}, entry)
+           end)
+
+    manifest = outdir |> Path.join("manifest.json") |> File.read!() |> Jason.decode!()
+
+    assert manifest["app.js"]["file"] == "js/app.js"
+    assert manifest["site.css"]["file"] == "css/site.css"
+    refute File.exists?(Path.join(outdir, "js/manifest.json"))
+    refute File.exists?(Path.join(outdir, "css/manifest.json"))
+  end
+
+  test "shared chunk references resolve through the manifest in both layouts", %{
+    root: root,
+    outdir: outdir
+  } do
+    File.write!(
+      Path.join(root, "shared.ts"),
+      "export const shared = () => console.log('shared');"
+    )
+
+    entries =
+      for name <- ["one", "two"] do
+        path = Path.join(root, "#{name}.ts")
+        File.write!(path, "import {shared} from './shared'; shared();")
+        path
+      end
+
+    for layout <- [:flat, :split], hash <- [false, true] do
+      output = Path.join(outdir, "#{layout}-#{hash}")
+
+      assert {:ok, result} =
+               Volt.build(
+                 entry: entries,
+                 root: root,
+                 outdir: output,
+                 output_layout: layout,
+                 hash: hash,
+                 format: :esm,
+                 code_splitting: true,
+                 minify: false,
+                 sourcemap: false,
+                 tailwind: []
+               )
+
+      assert [reference] = result.manifest["one.js"].imports
+      assert result.manifest["two.js"].imports == [reference]
+      assert %Volt.Builder.ManifestEntry{file: file} = result.manifest[reference]
+      assert File.regular?(Path.join(output, file))
+
+      assert Volt.Preload.tags(Path.join(output, "manifest.json"), entry: "one.js") ==
+               ~s(<link rel="modulepreload" href="/assets/#{file}">)
+    end
+  end
+
+  test "flat output resolves every emitted manifest path", %{root: root, outdir: outdir} do
+    assert {:ok, result} =
+             Volt.build(
+               entry: Path.join(root, "app.ts"),
+               root: root,
+               outdir: outdir,
+               output_layout: :flat,
+               hash: false,
+               minify: false,
+               sourcemap: false,
+               tailwind: [
+                 css: Path.join(root, "styles.css"),
+                 sources: [%{base: root, pattern: "**/*.html"}]
+               ]
+             )
+
+    assert result.manifest["app.js"].file == "app.js"
+    assert result.manifest["styles.css"].file == "styles.css"
+
+    for {_key, %Volt.Builder.ManifestEntry{file: file}} <- result.manifest do
+      assert File.regular?(Path.join(outdir, file))
+    end
+
+    refute File.dir?(Path.join(outdir, "js"))
+    refute File.dir?(Path.join(outdir, "css"))
+  end
+
+  test "rejects colliding manifest identities", %{root: root, outdir: outdir} do
+    plain_css = Path.join(root, "plain.css")
+    File.write!(plain_css, "body { color: red }")
+
+    assert {:error, {:manifest_collision, ["plain.css"]}} =
+             Volt.build(
+               entry: plain_css,
+               root: root,
+               outdir: outdir,
+               hash: true,
+               tailwind: [css: Path.join(root, "styles.css"), name: "plain"]
+             )
+
+    refute File.exists?(Path.join(outdir, "manifest.json"))
+  end
+
+  test "builds assets without Tailwind", %{root: root, outdir: outdir} do
+    assert {:ok, result} =
+             Volt.build(
+               entry: Path.join(root, "app.ts"),
+               root: root,
+               outdir: outdir,
+               hash: false,
+               minify: false,
+               sourcemap: false,
+               tailwind: []
+             )
+
+    assert result.styles == []
+    assert result.assets.css == nil
+    assert File.regular?(Path.join(outdir, "js/app.js"))
+    refute File.exists?(Path.join(outdir, "css/site.css"))
+  end
+end
diff --git a/test/volt/builder/artifact_test.exs b/test/volt/builder/artifact_test.exs
new file mode 100644
index 0000000..d02e483
--- /dev/null
+++ b/test/volt/builder/artifact_test.exs
@@ -0,0 +1,39 @@
+defmodule Volt.Builder.ArtifactTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.Builder.Artifact
+
+  test "asset identity is derived from content and preserves the extension" do
+    content = <<0, 255, 42>>
+    hash = Volt.Builder.Naming.hash(content)
+
+    assert Artifact.asset("/source/fonts/site.woff2", content) ==
+             %Artifact{file: "site-#{hash}.woff2", content: content}
+
+    assert Artifact.asset("/another/site.woff2", content) ==
+             Artifact.asset("/source/fonts/site.woff2", content)
+
+    refute Artifact.asset("site.woff2", content).file ==
+             Artifact.asset("site.woff2", content <> <<1>>).file
+  end
+
+  test "prepares JavaScript and its sourcemap without filesystem output" do
+    assert Artifact.javascript("app.js", "run();", "{}") == [
+             %Artifact{file: "app.js", content: "run();\n//# sourceMappingURL=app.js.map\n"},
+             %Artifact{file: "app.js.map", content: "{}"}
+           ]
+  end
+
+  test "hidden sourcemaps are emitted without a reference" do
+    assert Artifact.javascript("app.js", "run();", "{}", hidden: true) == [
+             %Artifact{file: "app.js", content: "run();"},
+             %Artifact{file: "app.js.map", content: "{}"}
+           ]
+  end
+
+  test "JavaScript without a sourcemap produces only one artifact" do
+    assert Artifact.javascript("app.js", "run();", nil) == [
+             %Artifact{file: "app.js", content: "run();"}
+           ]
+  end
+end
diff --git a/test/volt/builder/bundle_test.exs b/test/volt/builder/bundle_test.exs
index 7743a31..aa1a7a1 100644
--- a/test/volt/builder/bundle_test.exs
+++ b/test/volt/builder/bundle_test.exs
@@ -5,7 +5,10 @@ defmodule Volt.Builder.BundleTest do
 
   setup do
     tmp_dir =
-      Path.join(System.tmp_dir!(), "volt-builder-bundle-#{System.unique_integer([:positive])}")
+      Path.expand(
+        "volt-builder-bundle-#{System.unique_integer([:positive])}",
+        System.tmp_dir!()
+      )
 
     File.mkdir_p!(tmp_dir)
 
diff --git a/test/volt/builder/code_splitting_test.exs b/test/volt/builder/code_splitting_test.exs
index 7a73045..dde1043 100644
--- a/test/volt/builder/code_splitting_test.exs
+++ b/test/volt/builder/code_splitting_test.exs
@@ -2,6 +2,35 @@ defmodule Volt.Builder.CodeSplittingTest do
   use Volt.TestSupport.BuilderCase
 
   describe "build/1 code splitting" do
+    test "IIFE chunks read external globals once, inside the function scope" do
+      File.write!(Path.join(@fixture_dir, "src/global_lazy.js"), """
+      import { Presence } from 'phoenix'
+      export const run = () => console.log(Presence)
+      """)
+
+      File.write!(Path.join(@fixture_dir, "src/global_entry.js"), """
+      import { Socket } from 'phoenix'
+      console.log(new Socket('/socket'))
+      import('./global_lazy.js').then((m) => m.run())
+      """)
+
+      {:ok, _result} =
+        Volt.Builder.build(
+          entry: Path.join(@fixture_dir, "src/global_entry.js"),
+          outdir: @outdir,
+          hash: false,
+          minify: false,
+          sourcemap: false,
+          external: ["phoenix"]
+        )
+
+      for file <- Path.wildcard(Path.join(@outdir, "global_entry*.js")) do
+        js = File.read!(file)
+        assert [_once] = Regex.scan(~r/= Phoenix;/, js)
+        refute String.starts_with?(js, "const ")
+      end
+    end
+
     test "multi-entry ESM builds share common chunks" do
       File.write!(
         Path.join(@fixture_dir, "src/shared.ts"),
diff --git a/test/volt/builder/declarations_test.exs b/test/volt/builder/declarations_test.exs
new file mode 100644
index 0000000..40dfe9b
--- /dev/null
+++ b/test/volt/builder/declarations_test.exs
@@ -0,0 +1,247 @@
+defmodule Volt.Builder.DeclarationsTest do
+  use Volt.TestSupport.BuilderCase
+
+  alias Volt.Builder.Declarations
+
+  @node_modules Path.join(@fixture_dir, "node_modules")
+
+  setup do
+    File.mkdir_p!(Path.join(@node_modules, "vue"))
+
+    File.write!(
+      Path.join(@node_modules, "vue/package.json"),
+      Jason.encode!(%{"name" => "vue", "main" => "index.js", "types" => "index.d.ts"})
+    )
+
+    File.write!(
+      Path.join(@node_modules, "vue/index.js"),
+      "export const ref = (v) => ({ value: v })"
+    )
+
+    File.write!(
+      Path.join(@node_modules, "vue/index.d.ts"),
+      "export declare const ref: <T>(v: T) => { value: T };"
+    )
+
+    :ok
+  end
+
+  defp write!(path, source) do
+    path = Path.join(@fixture_dir, path)
+    File.mkdir_p!(Path.dirname(path))
+    File.write!(path, source)
+    path
+  end
+
+  defp context(plugins \\ []),
+    do: %Volt.Builder.Context{node_modules: @node_modules, plugins: plugins}
+
+  describe "bundle/2" do
+    test "bundles the declarations the entry exports reach into one module" do
+      write!("src/types.ts", """
+      /** Where a recording goes. */
+      export interface Target { url: string; retries?: number }
+      export type Mode = 'live' | 'replay'
+      export interface Unused { never: true }
+      """)
+
+      write!("src/recorder.ts", """
+      import type { Target, Mode } from './types'
+      import { ref } from 'vue'
+      export class Recorder {
+        mode: Mode = 'live'
+        start(target: Target): void { console.log(target, ref(1)) }
+      }
+      export default class Session { id: string = '' }
+      export const hidden: number = 1
+      """)
+
+      write!("src/extra.ts", """
+      export const EXTRA: string = 'extra'
+      export const ALSO: number = 2
+      """)
+
+      write!("src/index.ts", """
+      import { ref } from 'vue'
+      import Session from './recorder'
+      import type { Target as RecordTarget } from './types'
+      export { Recorder as Rec } from './recorder'
+      export * from './extra'
+      export type { Mode } from './types'
+      export const current: RecordTarget | null = null
+      export const session: typeof Session = Session
+      export const counter: ReturnType<typeof ref<number>> = ref(0)
+      declare module 'vue' { interface Augmented { fromIndex: true } }
+      """)
+
+      assert {:ok, dts} = Declarations.bundle(Path.join(@fixture_dir, "src/index.ts"), context())
+
+      # Imports of packages are hoisted once; project imports are gone.
+      assert String.starts_with?(dts, ~s(import { ref } from "vue";\n))
+      assert length(Regex.scan(~r/from "vue"/, dts)) == 1
+      refute dts =~ "./types"
+      refute dts =~ "./recorder"
+
+      # Declarations keep their docs and come before what refers to them.
+      assert dts =~ "/** Where a recording goes. */\ninterface Target {"
+      assert :binary.match(dts, "interface Target") < :binary.match(dts, "declare class Recorder")
+      assert dts =~ "type Mode = \"live\" | \"replay\";"
+      assert dts =~ "declare class Session {"
+      assert dts =~ "declare const EXTRA: string;"
+      assert dts =~ "declare const current: Target | null;"
+      assert dts =~ "declare module \"vue\" {"
+
+      # Only what the entry exports, under the entry's names.
+      assert dts =~ "export { ALSO, EXTRA, Mode, Recorder as Rec, counter, current, session };\n"
+      refute dts =~ "Unused"
+      refute dts =~ "hidden"
+      refute dts =~ "export declare"
+    end
+
+    test "tells apart the same name declared in two modules" do
+      write!("src/a.ts", """
+      /** A's options. */
+      export interface Options { a: true }
+      export const configureA: (o: Options) => void = () => {}
+      """)
+
+      write!("src/b.ts", """
+      export interface Options { b: true }
+      export const configureB: (o: Options) => Options = (o) => o
+      """)
+
+      write!("src/index.ts", """
+      export { configureA } from './a'
+      export { configureB } from './b'
+      export interface Options { index: true }
+      export const configure: (o: Options) => void = () => {}
+      """)
+
+      assert {:ok, dts} = Declarations.bundle(Path.join(@fixture_dir, "src/index.ts"), context())
+
+      assert dts =~ "interface Options {\n\tindex: true;\n}"
+      assert dts =~ "/** A's options. */\ninterface Options$1 {\n\ta: true;\n}"
+      assert dts =~ "interface Options$2 {\n\tb: true;\n}"
+      assert dts =~ "declare const configureA: (o: Options$1) => void;"
+      assert dts =~ "declare const configureB: (o: Options$2) => Options$2;"
+      assert dts =~ "declare const configure: (o: Options) => void;"
+      assert dts =~ "export { Options, configure, configureA, configureB };"
+    end
+
+    test "reports the module whose declarations cannot be emitted" do
+      write!("src/inferred.ts", "export function size() { return compute() }\n")
+      write!("src/index.ts", "export { size } from './inferred'\n")
+
+      assert {:error, {:declarations, path, [%{message: "TS9007" <> _, position: {1, 17}}]}} =
+               Declarations.bundle(Path.join(@fixture_dir, "src/index.ts"), context())
+
+      assert path == Path.join(@fixture_dir, "src/inferred.ts")
+    end
+
+    test "names the constructs it does not bundle" do
+      write!("src/ns.ts", "export const n: number = 1\n")
+      write!("src/index.ts", "import * as ns from './ns'\nexport const all: typeof ns = ns\n")
+
+      assert {:error, {:declarations, _path, "`import * as`" <> _}} =
+               Declarations.bundle(Path.join(@fixture_dir, "src/index.ts"), context())
+
+      write!("src/index.ts", "export * as ns from './ns'\n")
+
+      assert {:error, {:declarations, _path, "`export * as ns`" <> _}} =
+               Declarations.bundle(Path.join(@fixture_dir, "src/index.ts"), context())
+    end
+
+    test "declares a component through its plugin" do
+      write!("src/Button.vue", """
+      <script setup lang="ts">
+      defineProps<{ variant?: 'primary' | 'ghost' }>()
+      </script>
+      <template><button /></template>
+      """)
+
+      write!("src/index.ts", """
+      import Button from './Button.vue'
+      export const button: typeof Button = Button
+      """)
+
+      assert {:ok, dts} =
+               Declarations.bundle(
+                 Path.join(@fixture_dir, "src/index.ts"),
+                 context([Volt.Plugin.Vue])
+               )
+
+      assert dts =~ "type Props = { variant?: 'primary' | 'ghost' };"
+      assert dts =~ "declare const __vize_component__:"
+      assert dts =~ "declare const button: typeof __vize_component__;"
+      assert dts =~ "export { button };"
+    end
+  end
+
+  describe "build/1 with declarations" do
+    test "writes one .d.ts per entry beside its bundle, without a hash" do
+      write!("src/lib.ts", """
+      import { ref } from 'vue'
+      export const count: ReturnType<typeof ref<number>> = ref(0)
+      export function reset(): void { count.value = 0 }
+      """)
+
+      assert {:ok, result} =
+               Volt.Builder.build(
+                 entry: Path.join(@fixture_dir, "src/lib.ts"),
+                 outdir: @outdir,
+                 node_modules: @node_modules,
+                 format: :esm,
+                 name: "lib",
+                 declarations: true,
+                 minify: false,
+                 sourcemap: false
+               )
+
+      assert [%Volt.Builder.OutputFile{path: path}] = result.declarations
+      assert path == Path.join(@outdir, "lib.d.ts")
+      assert File.read!(path) =~ "export { count, reset };"
+      assert Path.basename(result.js.path) =~ ~r/^lib-[a-f0-9]+\.js$/
+    end
+
+    test "writes declarations for each of several ESM entries" do
+      write!("src/one.ts", "export const one: number = 1\n")
+
+      write!(
+        "src/two.ts",
+        "import { one } from './one'\nexport const two: typeof one = one + 1\n"
+      )
+
+      assert {:ok, result} =
+               Volt.Builder.build(
+                 entry: [
+                   Path.join(@fixture_dir, "src/one.ts"),
+                   Path.join(@fixture_dir, "src/two.ts")
+                 ],
+                 outdir: @outdir,
+                 node_modules: @node_modules,
+                 format: :esm,
+                 declarations: true,
+                 minify: false,
+                 sourcemap: false
+               )
+
+      assert Enum.map(result.declarations, &Path.basename(&1.path)) == ["one.d.ts", "two.d.ts"]
+      assert File.read!(Path.join(@outdir, "two.d.ts")) =~ "declare const one: number;"
+    end
+
+    test "fails the build with the module that has no explicit types" do
+      write!("src/lib.ts", "export const value = compute()\n")
+
+      assert {:error, {:declarations, path, [%{message: "TS9010" <> _}]}} =
+               Volt.Builder.build(
+                 entry: Path.join(@fixture_dir, "src/lib.ts"),
+                 outdir: @outdir,
+                 node_modules: @node_modules,
+                 format: :esm,
+                 declarations: true
+               )
+
+      assert path == Path.join(@fixture_dir, "src/lib.ts")
+    end
+  end
+end
diff --git a/test/volt/builder/manifest_entry_test.exs b/test/volt/builder/manifest_entry_test.exs
new file mode 100644
index 0000000..f7cfcd2
--- /dev/null
+++ b/test/volt/builder/manifest_entry_test.exs
@@ -0,0 +1,36 @@
+defmodule Volt.Builder.ManifestEntryTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.Builder.ManifestEntry
+
+  test "stylesheet traversal is dependency-first, deduplicated, and cycle-safe" do
+    manifest = %{
+      "app" => %ManifestEntry{imports: ["a", "b"], css: ["app.css"], dynamicImports: ["lazy"]},
+      "a" => %ManifestEntry{imports: ["b"], css: ["a.css"]},
+      "b" => %ManifestEntry{imports: ["a"], css: ["shared.css", "a.css"]},
+      "lazy" => %ManifestEntry{css: ["lazy.css"]}
+    }
+
+    assert ManifestEntry.stylesheets(manifest, "app") == ["shared.css", "a.css", "app.css"]
+  end
+
+  test "output prefixes do not alter manifest references or source identity" do
+    entry = %ManifestEntry{
+      src: "src/app.ts",
+      file: "app-hash.js",
+      imports: ["shared"],
+      dynamicImports: ["lazy"],
+      css: ["app-hash.css"],
+      assets: ["logo-hash.svg"]
+    }
+
+    assert ManifestEntry.prefix_paths(entry, "js") == %ManifestEntry{
+             src: "src/app.ts",
+             file: "js/app-hash.js",
+             imports: ["shared"],
+             dynamicImports: ["lazy"],
+             css: ["js/app-hash.css"],
+             assets: ["js/logo-hash.svg"]
+           }
+  end
+end
diff --git a/test/volt/builder/naming_test.exs b/test/volt/builder/naming_test.exs
new file mode 100644
index 0000000..43c7dd1
--- /dev/null
+++ b/test/volt/builder/naming_test.exs
@@ -0,0 +1,53 @@
+defmodule Volt.Builder.NamingTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.Builder.Naming
+
+  test "preserves eight-character lowercase SHA-256 names" do
+    assert Naming.hash("") == "e3b0c442"
+    assert Naming.hash("hello") == "2cf24dba"
+    assert Naming.hash(["he", "llo"]) == "2cf24dba"
+  end
+
+  test "replaces characters that are invalid in Windows filenames" do
+    assert Naming.file_path("virtual:volt/test?<entry>|.js") ==
+             "virtual_volt/test__entry__.js"
+  end
+
+  test "normalizes separators, trailing dots, and reserved Windows names" do
+    assert Naming.file_path("scope\\CON.js/trailing. ") == "scope/_CON.js/trailing"
+  end
+
+  test "derives filesystem-safe entry names" do
+    assert Naming.entry_name("virtual:volt/test.ts") == "test"
+    assert Naming.entry_name("ignored.ts", "CON:entry") == "CON_entry"
+  end
+
+  test "derives module labels and JavaScript wrapper extensions" do
+    root = Path.join(System.tmp_dir!(), "volt-naming-root")
+
+    assert Naming.module_label(Path.join(root, "src/data.json"), root) == "src/data.json.js"
+
+    assert Naming.module_label(Path.join(root, "src/style.css") <> "?raw", root) ==
+             "src/style.css.raw.js"
+
+    assert Naming.module_label(Path.join(root, "node_modules/pkg/index.js"), root) ==
+             "pkg/index.js"
+  end
+
+  test "adds stable unique suffixes before file extensions" do
+    used = MapSet.new(["src/index.js"])
+    unique = Naming.unique("src/index.js", "virtual:first", used)
+
+    assert unique =~ ~r|^src/index-[0-9a-f]{10}\.js$|
+    assert Naming.unique("src/index.js", "virtual:first", used) == unique
+    assert Naming.unique("src/other.js", "virtual:other", used) == "src/other.js"
+  end
+
+  test "increments a stable suffix when the digest candidate is also used" do
+    first = Naming.unique("entry", "virtual:entry", MapSet.new(["entry"]))
+    used = MapSet.new(["entry", first])
+
+    assert Naming.unique("entry", "virtual:entry", used) == first <> "-2"
+  end
+end
diff --git a/test/volt/builder/output_test.exs b/test/volt/builder/output_test.exs
new file mode 100644
index 0000000..99d310c
--- /dev/null
+++ b/test/volt/builder/output_test.exs
@@ -0,0 +1,57 @@
+defmodule Volt.Builder.OutputTest do
+  use ExUnit.Case, async: true
+
+  @moduletag :tmp_dir
+
+  test "successful preparation returns output without creating its directory", %{tmp_dir: root} do
+    outdir = Path.join(root, "unpublished")
+
+    context = %Volt.Builder.BuildContext{
+      outdir: outdir,
+      hash: false,
+      ctx: %Volt.Builder.OutputContext{},
+      bundle_opts: [format: :esm, minify: false, sourcemap: false]
+    }
+
+    assert {:ok, result, plan} =
+             Volt.Builder.Output.prepare_single(
+               Path.join(root, "app.js"),
+               "app",
+               %Volt.Builder.Compiled{
+                 scripts: [{"app.js", "console.log('prepared');"}],
+                 styles: ["body { color: red }"]
+               },
+               context
+             )
+
+    assert result.js.path == Path.join(outdir, "app.js")
+    assert Enum.map(plan.artifacts, & &1.file) == ["app.css", "app.js"]
+    refute File.exists?(outdir)
+  end
+
+  test "late CSS failure leaves the existing script untouched", %{tmp_dir: root} do
+    output = Path.join(root, "app.js")
+    File.write!(output, "previous generation")
+
+    context = %Volt.Builder.BuildContext{
+      outdir: root,
+      hash: false,
+      ctx: %Volt.Builder.OutputContext{},
+      bundle_opts: [format: :esm, minify: false, sourcemap: false]
+    }
+
+    assert {:error, {:css_compile_failed, _}} =
+             Volt.Builder.Output.build_single(
+               Path.join(root, "app.js"),
+               "app",
+               %Volt.Builder.Compiled{
+                 scripts: [{"app.js", "console.log('next generation');"}],
+                 styles: ["a { color: } }"]
+               },
+               context
+             )
+
+    assert File.read!(output) == "previous generation"
+    assert File.ls!(root) == ["app.js"]
+  end
+end
diff --git a/test/volt/builder/plan_test.exs b/test/volt/builder/plan_test.exs
new file mode 100644
index 0000000..b8deefc
--- /dev/null
+++ b/test/volt/builder/plan_test.exs
@@ -0,0 +1,92 @@
+defmodule Volt.Builder.PlanTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.Builder.{Artifact, Plan, Writer}
+
+  @moduletag :tmp_dir
+
+  test "validates manifest keys independently of output filenames" do
+    {:ok, plan} =
+      Plan.new([
+        %Artifact{file: "js/main-hash.js", content: ""},
+        %Artifact{file: "js/shared-hash.js", content: ""}
+      ])
+
+    manifest = %{
+      "main" => %Volt.Builder.ManifestEntry{file: "js/main-hash.js", imports: ["shared"]},
+      "shared" => %Volt.Builder.ManifestEntry{file: "js/shared-hash.js", imports: ["main"]}
+    }
+
+    assert :ok = Plan.validate_manifest(plan, manifest)
+
+    broken =
+      Map.put(manifest, "main", %Volt.Builder.ManifestEntry{
+        file: "js/main-hash.js",
+        imports: ["js/shared-hash.js"],
+        dynamicImports: ["lazy"],
+        css: ["missing.css"],
+        assets: ["missing.svg"]
+      })
+
+    assert {:error, {:invalid_manifest, errors}} = Plan.validate_manifest(plan, broken)
+    assert {:missing_manifest_entry, "main", "js/shared-hash.js"} in errors
+    assert {:missing_manifest_entry, "main", "lazy"} in errors
+    assert {:missing_artifact, "main", "missing.css"} in errors
+    assert {:missing_artifact, "main", "missing.svg"} in errors
+    assert length(errors) == 4
+  end
+
+  test "deduplicates identical outputs and orders the plan" do
+    a = %Artifact{file: "a.js", content: "a"}
+    b = %Artifact{file: "nested/b.js", content: "b"}
+    assert {:ok, %Plan{artifacts: [^a, ^b]}} = Plan.new([b, a, b])
+  end
+
+  test "rejects conflicting output before replacing a previous file", %{tmp_dir: root} do
+    previous = Path.join(root, "app.js")
+    File.write!(previous, "previous")
+
+    result =
+      with {:ok, plan} <-
+             Plan.new([
+               %Artifact{file: "app.js", content: "first"},
+               %Artifact{file: "app.js", content: "second"}
+             ]) do
+        Writer.write_plan(root, plan)
+      end
+
+    assert result == {:error, {:output_collision, "app.js"}}
+    assert File.read!(previous) == "previous"
+  end
+
+  test "rejects unsafe and ambiguous relative paths" do
+    for file <- [
+          "",
+          ".",
+          "..",
+          "../app.js",
+          "/app.js",
+          "nested/../app.js",
+          "nested//app.js",
+          "nested/./app.js",
+          "C:\\app.js",
+          "nested\\app.js",
+          "bad\0.js"
+        ] do
+      assert {:error, {:invalid_output_path, ^file}} =
+               Plan.new([%Artifact{file: file, content: ""}])
+    end
+  end
+
+  test "writes all validated artifacts including nested outputs", %{tmp_dir: root} do
+    assert {:ok, plan} =
+             Plan.new([
+               %Artifact{file: "js/app.js", content: "run();"},
+               %Artifact{file: "css/app.css", content: "body{}"}
+             ])
+
+    assert :ok = Writer.write_plan(root, plan)
+    assert File.read!(Path.join(root, "js/app.js")) == "run();"
+    assert File.read!(Path.join(root, "css/app.css")) == "body{}"
+  end
+end
diff --git a/test/volt/builder/plugins_and_virtual_modules_test.exs b/test/volt/builder/plugins_and_virtual_modules_test.exs
index 5e2cbd1..ac5040e 100644
--- a/test/volt/builder/plugins_and_virtual_modules_test.exs
+++ b/test/volt/builder/plugins_and_virtual_modules_test.exs
@@ -19,6 +19,7 @@ defmodule Volt.Builder.PluginsAndVirtualModulesTest do
 
       {:ok, result} =
         Volt.Builder.build(
+          external: ["vue"],
           entry: Path.join(@fixture_dir, "src/glob_app.ts"),
           outdir: @outdir,
           minify: false,
@@ -183,6 +184,7 @@ defmodule Volt.Builder.PluginsAndVirtualModulesTest do
 
       {:ok, result} =
         Volt.Builder.build(
+          external: ["vue"],
           entry: Path.join(@fixture_dir, "src/app.ts"),
           outdir: @outdir,
           minify: false,
@@ -224,6 +226,7 @@ defmodule Volt.Builder.PluginsAndVirtualModulesTest do
 
       {:ok, result} =
         Volt.Builder.build(
+          external: ["vue"],
           entry: Path.join(@fixture_dir, "src/alias_app.ts"),
           outdir: @outdir,
           minify: false,
@@ -306,8 +309,8 @@ defmodule Volt.Builder.PluginsAndVirtualModulesTest do
           plugins: [VirtualModPlugin]
         )
 
-      assert result.manifest["virtual:plain.js"].file == "virtual:plain.js"
-      assert File.read!(Path.join(@outdir, "virtual:plain.js")) =~ "123"
+      assert result.manifest["virtual_plain.js"].file == "virtual_plain.js"
+      assert File.read!(Path.join(@outdir, "virtual_plain.js")) =~ "123"
     end
 
     test "multiple virtual build entries get stable manifest keys" do
@@ -327,6 +330,25 @@ defmodule Volt.Builder.PluginsAndVirtualModulesTest do
       assert result.manifest["entry-b.js"].file == "entry-b.js"
     end
 
+    test "virtual entry names remain unique after filesystem sanitization" do
+      {:ok, result} =
+        Volt.Builder.build(
+          entry: ["virtual:collision/entry:a", "virtual:collision/entry|a"],
+          outdir: @outdir,
+          hash: false,
+          minify: false,
+          sourcemap: false,
+          plugins: [VirtualModPlugin]
+        )
+
+      files = result.manifest |> Map.values() |> Enum.map(& &1.file) |> Enum.sort()
+
+      assert length(files) == 2
+      assert Enum.uniq(files) == files
+      assert Enum.any?(files, &(&1 == "entry_a.js"))
+      assert Enum.any?(files, &String.match?(&1, ~r/^entry_a-[0-9a-f]{10}\.js$/))
+    end
+
     test "virtual build entries can import stylesheet dependencies" do
       File.write!(Path.join(@fixture_dir, "src/style.css"), ".foo { color: red }")
 
diff --git a/test/volt/builder/publication_test.exs b/test/volt/builder/publication_test.exs
new file mode 100644
index 0000000..136e2b4
--- /dev/null
+++ b/test/volt/builder/publication_test.exs
@@ -0,0 +1,67 @@
+defmodule Volt.Builder.PublicationTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.Builder.{Artifact, Plan, Publication}
+  @moduletag :tmp_dir
+
+  test "rejects destination symlinks before replacing any files", %{tmp_dir: root} do
+    outdir = Path.join(root, "output")
+    outside = Path.join(root, "outside")
+    File.mkdir_p!(outdir)
+    File.mkdir_p!(outside)
+    File.write!(Path.join(outdir, "app.js"), "previous")
+    File.ln_s!(outside, Path.join(outdir, "linked"))
+
+    {:ok, plan} =
+      Plan.new([
+        %Artifact{file: "app.js", content: "replacement"},
+        %Artifact{file: "linked/escape.js", content: "escape"}
+      ])
+
+    assert {:error, {:symlink_destination, _}} = Publication.write(outdir, plan)
+    assert File.read!(Path.join(outdir, "app.js")) == "previous"
+    assert File.ls!(outside) == []
+  end
+
+  test "staging failure leaves existing output unchanged", %{tmp_dir: root} do
+    outdir = Path.join(root, "output")
+    File.mkdir_p!(outdir)
+    File.write!(Path.join(outdir, "app.js"), "previous")
+    # A file/directory conflict is a deterministic failure without permission assumptions.
+    plan = %Plan{
+      artifacts: [
+        %Artifact{file: "app.js", content: "replacement"},
+        %Artifact{file: "nested", content: "file"},
+        %Artifact{file: "nested/child.js", content: "child"}
+      ]
+    }
+
+    assert {:error, {:staging_failed, "nested/child.js", _}} = Publication.write(outdir, plan)
+    assert File.read!(Path.join(outdir, "app.js")) == "previous"
+    assert File.ls!(root) == ["output"]
+  end
+
+  test "commit failure does not replace manifest", %{tmp_dir: root} do
+    outdir = Path.join(root, "output")
+    File.mkdir_p!(Path.join(outdir, "blocked.js"))
+    File.write!(Path.join(outdir, "manifest.json"), "previous")
+
+    {:ok, plan} =
+      Plan.new([
+        %Artifact{file: "blocked.js", content: "next"},
+        %Artifact{file: "manifest.json", content: "next manifest"}
+      ])
+
+    assert {:error, {:publication_failed, "blocked.js", _}} = Publication.write(outdir, plan)
+    assert File.read!(Path.join(outdir, "manifest.json")) == "previous"
+    assert File.ls!(root) == ["output"]
+  end
+
+  test "successful publication preserves unrelated static files", %{tmp_dir: root} do
+    File.write!(Path.join(root, "robots.txt"), "keep")
+    {:ok, plan} = Plan.new([%Artifact{file: "app.js", content: "new"}])
+    assert :ok = Publication.write(root, plan)
+    assert File.read!(Path.join(root, "robots.txt")) == "keep"
+    assert File.read!(Path.join(root, "app.js")) == "new"
+  end
+end
diff --git a/test/volt/builder/resolution_test.exs b/test/volt/builder/resolution_test.exs
index a505fbe..95ccaf0 100644
--- a/test/volt/builder/resolution_test.exs
+++ b/test/volt/builder/resolution_test.exs
@@ -84,6 +84,137 @@ defmodule Volt.Builder.ResolutionTest do
       assert js =~ "b-"
     end
 
+    test "resolves bare imports from the importer's scoped package directory" do
+      app_packages = Path.join(@fixture_dir, "node_modules")
+      framework_root = Path.join(@fixture_dir, "framework")
+      framework_packages = Path.join(framework_root, "node_modules")
+
+      for {package_dir, value} <- [
+            {Path.join(app_packages, "shared-pkg"), "app-package"},
+            {Path.join(framework_packages, "shared-pkg"), "framework-package"}
+          ] do
+        File.mkdir_p!(package_dir)
+        File.write!(Path.join(package_dir, "package.json"), ~s({"main":"index.js"}))
+        File.write!(Path.join(package_dir, "index.js"), "export default #{inspect(value)};")
+      end
+
+      framework_dep = Path.join(framework_packages, "framework-dep")
+      File.mkdir_p!(framework_dep)
+      File.write!(Path.join(framework_dep, "package.json"), ~s({"main":"index.js"}))
+      File.write!(Path.join(framework_dep, "index.js"), "export default 'scoped-transitive';")
+
+      File.write!(Path.join(framework_packages, "shared-pkg/index.js"), """
+      import dep from 'framework-dep'
+      export default 'framework-package-' + dep
+      """)
+
+      File.mkdir_p!(framework_root)
+
+      File.write!(Path.join(framework_root, "runtime.js"), """
+      import value from 'shared-pkg'
+      export const frameworkValue = value
+      """)
+
+      File.write!(Path.join(@fixture_dir, "src/scoped_packages_app.js"), """
+      import appValue from 'shared-pkg'
+      import { frameworkValue } from '../framework/runtime.js'
+      console.log(appValue, frameworkValue)
+      """)
+
+      {:ok, result} =
+        Volt.Builder.build(
+          entry: Path.join(@fixture_dir, "src/scoped_packages_app.js"),
+          outdir: @outdir,
+          minify: false,
+          sourcemap: false,
+          node_modules: app_packages,
+          package_scopes: [{framework_root, framework_packages}]
+        )
+
+      js = File.read!(result.js.path)
+      assert js =~ "app-package"
+      assert js =~ "framework-package"
+      assert js =~ "scoped-transitive"
+    end
+
+    test "resolves a package's dependency from its nested node_modules" do
+      files = %{
+        "node_modules/a/package.json" => ~s({"name":"a","version":"1.0.0","main":"index.js"}),
+        "node_modules/a/index.js" => ~s(import { b } from "b"; export const a = "a+" + b;),
+        "node_modules/a/node_modules/b/package.json" =>
+          ~s({"name":"b","version":"1.0.0","main":"index.js"}),
+        "node_modules/a/node_modules/b/index.js" => ~s(export const b = "nested-b";),
+        "src/nested_app.js" => ~s(import { a } from "a"; globalThis.out = a;)
+      }
+
+      for {path, contents} <- files do
+        path = Path.join(@fixture_dir, path)
+        File.mkdir_p!(Path.dirname(path))
+        File.write!(path, contents)
+      end
+
+      {:ok, result} =
+        Volt.Builder.build(
+          entry: Path.join(@fixture_dir, "src/nested_app.js"),
+          outdir: @outdir,
+          node_modules: Path.join(@fixture_dir, "node_modules"),
+          minify: false,
+          sourcemap: false
+        )
+
+      js = File.read!(result.js.path)
+      assert js =~ "nested-b"
+      refute js =~ "})(b)"
+    end
+
+    test "leaves OXC runtime helpers to the bundler, which inlines them" do
+      File.mkdir_p!(Path.join(@fixture_dir, "src"))
+
+      File.write!(Path.join(@fixture_dir, "src/helper_app.js"), """
+      import _defineProperty from "@oxc-project/runtime/helpers/defineProperty"
+      class A { constructor() { _defineProperty(this, "x", 1) } }
+      globalThis.a = new A()
+      """)
+
+      {:ok, result} =
+        Volt.Builder.build(
+          entry: Path.join(@fixture_dir, "src/helper_app.js"),
+          outdir: @outdir,
+          minify: false,
+          sourcemap: false
+        )
+
+      js = File.read!(result.js.path)
+      assert js =~ "function _defineProperty"
+      refute js =~ "@oxc-project/runtime/helpers"
+    end
+
+    test "fails the build for a bare import of a package that is not installed" do
+      File.mkdir_p!(Path.join(@fixture_dir, "src"))
+
+      File.write!(
+        Path.join(@fixture_dir, "src/missing_app.js"),
+        ~s|import { x } from "not-installed"; console.log(x)|
+      )
+
+      assert {:error, {:not_found, "not-installed"}} =
+               Volt.Builder.build(
+                 entry: Path.join(@fixture_dir, "src/missing_app.js"),
+                 outdir: @outdir,
+                 minify: false,
+                 sourcemap: false
+               )
+
+      assert {:ok, _result} =
+               Volt.Builder.build(
+                 entry: Path.join(@fixture_dir, "src/missing_app.js"),
+                 outdir: @outdir,
+                 external: ["not-installed"],
+                 minify: false,
+                 sourcemap: false
+               )
+    end
+
     test "resolves package imports from nearest package imports map" do
       File.mkdir_p!(Path.join(@fixture_dir, "node_modules/pkg/src/internal"))
 
@@ -132,6 +263,7 @@ defmodule Volt.Builder.ResolutionTest do
 
       {:ok, result} =
         Volt.Builder.build(
+          external: ["react"],
           entry: Path.join(@fixture_dir, "src/jsx_app.js"),
           outdir: @outdir,
           minify: false,
@@ -310,6 +442,133 @@ defmodule Volt.Builder.ResolutionTest do
       assert js =~ "ref("
     end
 
+    test "leaves Node built-in subpaths out, as it does the built-ins themselves" do
+      File.write!(Path.join(@fixture_dir, "src/builtin_subpath_app.js"), """
+      import { setTimeout as wait } from 'timers/promises'
+      import { readFile } from 'node:fs/promises'
+      export const run = () => wait(1).then(() => readFile('x'))
+      """)
+
+      assert {:ok, result} =
+               Volt.Builder.build(
+                 entry: Path.join(@fixture_dir, "src/builtin_subpath_app.js"),
+                 outdir: @outdir,
+                 format: :esm,
+                 minify: false,
+                 sourcemap: false
+               )
+
+      js = File.read!(result.js.path)
+      assert js =~ ~s(from "timers/promises")
+      assert js =~ ~s(from "node:fs/promises")
+    end
+
+    test "maps what a package's browser field sets to false to an empty module" do
+      package = Path.join(@fixture_dir, "node_modules/fake-timers")
+      File.mkdir_p!(package)
+
+      File.write!(
+        Path.join(package, "package.json"),
+        Jason.encode!(%{
+          "name" => "fake-timers",
+          "main" => "index.js",
+          "browser" => %{"timers/promises" => false, "./clock.js" => "./clock-browser.js"}
+        })
+      )
+
+      File.write!(Path.join(package, "index.js"), """
+      let promises = null
+      try { promises = require('timers/promises') } catch (e) {}
+      const clock = require('./clock.js')
+      module.exports = { promises, clock }
+      """)
+
+      File.write!(Path.join(package, "clock.js"), "module.exports = 'node clock'")
+      File.write!(Path.join(package, "clock-browser.js"), "module.exports = 'browser clock'")
+
+      File.write!(Path.join(@fixture_dir, "src/browser_field_app.js"), """
+      import timers from 'fake-timers'
+      console.log(timers.promises, timers.clock)
+      """)
+
+      assert {:ok, result} =
+               Volt.Builder.build(
+                 entry: Path.join(@fixture_dir, "src/browser_field_app.js"),
+                 outdir: @outdir,
+                 minify: false,
+                 sourcemap: false
+               )
+
+      js = File.read!(result.js.path)
+      refute js =~ "timers/promises"
+      assert js =~ "browser clock"
+      refute js =~ "node clock"
+    end
+
+    test "keeps external imports in ES module output" do
+      File.write!(Path.join(@fixture_dir, "src/external_app.js"), """
+      import { Socket } from 'phoenix'
+      import 'phoenix/side-effect'
+      console.log(new Socket('/socket'))
+      """)
+
+      {:ok, result} =
+        Volt.Builder.build(
+          entry: Path.join(@fixture_dir, "src/external_app.js"),
+          outdir: @outdir,
+          format: :esm,
+          minify: false,
+          sourcemap: false,
+          external: %{"phoenix" => "Phoenix"}
+        )
+
+      js = File.read!(result.js.path)
+      assert js =~ ~r/import \{ Socket \} from "phoenix"/
+      assert js =~ ~s(import "phoenix/side-effect")
+      refute js =~ "= Phoenix"
+    end
+
+    test "requires external imports in CommonJS output" do
+      File.write!(Path.join(@fixture_dir, "src/external_cjs_app.js"), """
+      import { Socket } from 'phoenix'
+      console.log(new Socket('/socket'))
+      """)
+
+      {:ok, result} =
+        Volt.Builder.build(
+          entry: Path.join(@fixture_dir, "src/external_cjs_app.js"),
+          outdir: @outdir,
+          format: :cjs,
+          minify: false,
+          sourcemap: false,
+          external: ["phoenix"]
+        )
+
+      js = File.read!(result.js.path)
+      assert js =~ ~s[require("phoenix")]
+      refute js =~ "= Phoenix"
+    end
+
+    test "reads external imports from globals in IIFE output" do
+      File.write!(Path.join(@fixture_dir, "src/external_iife_app.js"), """
+      import { Socket } from 'phoenix'
+      console.log(new Socket('/socket'))
+      """)
+
+      {:ok, result} =
+        Volt.Builder.build(
+          entry: Path.join(@fixture_dir, "src/external_iife_app.js"),
+          outdir: @outdir,
+          minify: false,
+          sourcemap: false,
+          external: %{"phoenix" => "PhoenixGlobal"}
+        )
+
+      js = File.read!(result.js.path)
+      assert js =~ "const { Socket } = PhoenixGlobal;"
+      refute js =~ ~s(from "phoenix")
+    end
+
     test "resolves .js imports to .ts files when .js does not exist" do
       File.write!(Path.join(@fixture_dir, "src/utils.ts"), """
       export const helper = 'ts-resolved'
diff --git a/test/volt/builder/output/css_test.exs b/test/volt/builder/stylesheets_test.exs
similarity index 81%
rename from test/volt/builder/output/css_test.exs
rename to test/volt/builder/stylesheets_test.exs
index c0028c8..a9f8b9a 100644
--- a/test/volt/builder/output/css_test.exs
+++ b/test/volt/builder/stylesheets_test.exs
@@ -1,7 +1,7 @@
-defmodule Volt.Builder.Output.CSSTest do
+defmodule Volt.Builder.StylesheetsTest do
   use ExUnit.Case, async: false
 
-  @fixture_dir Path.join(System.tmp_dir!(), "volt-builder-css-test")
+  @fixture_dir Path.expand("volt-builder-css-test", System.tmp_dir!())
   @outdir Path.join(@fixture_dir, "dist")
 
   setup do
@@ -16,6 +16,56 @@ defmodule Volt.Builder.Output.CSSTest do
   end
 
   describe "CSS production builds" do
+    @tag :tmp_dir
+    test "emits assets from nested local and package imports", %{tmp_dir: root} do
+      File.mkdir_p!(Path.join(root, "nested"))
+      package = Path.join(root, "node_modules/theme")
+      File.mkdir_p!(package)
+
+      File.write!(
+        Path.join(package, "package.json"),
+        ~s({"name":"theme","exports":{".":"./index.css"}})
+      )
+
+      File.write!(
+        Path.join(package, "index.css"),
+        "@font-face { font-family: Test; src: url('./font.woff2') }"
+      )
+
+      File.write!(Path.join(package, "font.woff2"), <<0, 1, 2>>)
+
+      File.write!(
+        Path.join(root, "nested/theme.css"),
+        ".logo { background: url('./logo.svg?v=1#mark') }"
+      )
+
+      File.write!(Path.join(root, "nested/logo.svg"), "<svg/>")
+      entry = Path.join(root, "app.css")
+      File.write!(entry, "@import './nested/theme.css'; @import 'theme';")
+      output = Path.join(root, "dist")
+
+      assert {:ok, result} =
+               Volt.Builder.build(
+                 entry: entry,
+                 root: root,
+                 outdir: output,
+                 node_modules: Path.join(root, "node_modules"),
+                 hash: false,
+                 minify: false,
+                 asset_url_prefix: "https://cdn.example/assets"
+               )
+
+      css = File.read!(result.css.path)
+
+      for source <- ["nested/logo.svg", "node_modules/theme/font.woff2"] do
+        file = Map.fetch!(result.manifest, source).file
+        assert File.regular?(Path.join(output, file))
+        assert css =~ "https://cdn.example/assets/#{file}"
+      end
+
+      assert css =~ "?v=1#mark"
+    end
+
     test "CSS-only JS entry builds with sourcemap enabled" do
       File.write!(Path.join(@fixture_dir, "src/styles.css"), "body { color: red; }")
       File.write!(Path.join(@fixture_dir, "src/css_only.js"), "import './styles.css'")
@@ -45,6 +95,7 @@ defmodule Volt.Builder.Output.CSSTest do
 
       {:ok, result} =
         Volt.Builder.build(
+          external: ["vue"],
           entry: Path.join(@fixture_dir, "src/main.ts"),
           outdir: @outdir,
           minify: false,
@@ -184,6 +235,7 @@ defmodule Volt.Builder.Output.CSSTest do
 
       {:ok, result} =
         Volt.Builder.build(
+          external: ["vue"],
           entry: Path.join(@fixture_dir, "src/vue_css_asset.ts"),
           outdir: @outdir,
           minify: false,
diff --git a/test/volt/builder/workers_and_assets_test.exs b/test/volt/builder/workers_and_assets_test.exs
index 57239b0..b602b6e 100644
--- a/test/volt/builder/workers_and_assets_test.exs
+++ b/test/volt/builder/workers_and_assets_test.exs
@@ -2,6 +2,54 @@ defmodule Volt.Builder.WorkersAndAssetsTest do
   use Volt.TestSupport.BuilderCase
 
   describe "build/1 workers, assets, and externals" do
+    test "preserves worker manifest and asset metadata" do
+      entry = Path.join(@fixture_dir, "parent.ts")
+      worker = Path.join(@fixture_dir, "worker.ts")
+      File.write!(entry, "new Worker(new URL('./worker.ts', import.meta.url), {type: 'module'})")
+      File.write!(worker, "import logo from './logo.svg?url'; self.postMessage(logo)")
+      File.write!(Path.join(@fixture_dir, "logo.svg"), "<svg/>")
+
+      assert {:ok, result} =
+               Volt.Builder.build(
+                 entry: entry,
+                 outdir: @outdir,
+                 root: @fixture_dir,
+                 hash: false,
+                 minify: false,
+                 sourcemap: false
+               )
+
+      assert result.manifest["worker.js"].file == "worker.js"
+      assert %Volt.Builder.ManifestEntry{file: image} = result.manifest["logo.svg"]
+      assert image in result.manifest["worker.js"].assets
+      assert Enum.any?(result.chunks, &(Path.basename(&1.path) == "worker.js"))
+      assert Path.basename(result.js.path) == "parent.js"
+    end
+
+    test "does not copy imported assets before a later CSS failure" do
+      source = Path.join(@fixture_dir, "asset_failure.ts")
+
+      File.write!(
+        source,
+        "import image from './logo.svg?url'; import './broken.css'; console.log(image);"
+      )
+
+      File.write!(Path.join(@fixture_dir, "logo.svg"), "<svg/>")
+      File.write!(Path.join(@fixture_dir, "broken.css"), "a { color: } }")
+      before_files = Path.wildcard(Path.join(@outdir, "**/*"))
+
+      assert {:error, _} =
+               Volt.Builder.build(
+                 entry: source,
+                 outdir: @outdir,
+                 hash: false,
+                 minify: false,
+                 sourcemap: false
+               )
+
+      assert Path.wildcard(Path.join(@outdir, "**/*")) == before_files
+    end
+
     test "rewrites workers by importer path instead of basename" do
       File.mkdir_p!(Path.join(@fixture_dir, "src/a"))
       File.mkdir_p!(Path.join(@fixture_dir, "src/b"))
diff --git a/test/volt/cache_test.exs b/test/volt/cache_test.exs
index 41f13a8..b0fc709 100644
--- a/test/volt/cache_test.exs
+++ b/test/volt/cache_test.exs
@@ -6,6 +6,24 @@ defmodule Volt.CacheTest do
     :ok
   end
 
+  test "sessions isolate cached content and eviction" do
+    path = "/shared/app.css"
+    a = %Volt.DevServer.CacheEntry{code: "a"}
+    b = %Volt.DevServer.CacheEntry{code: "b"}
+    Volt.Cache.put(path, 1, a, :site_a)
+    Volt.Cache.put(path, 1, b, :site_b)
+    Volt.Cache.put(path <> "?import", 1, a, :site_a)
+    assert Volt.Cache.get(path, 1, :site_a) == a
+    assert Volt.Cache.get(path, 1, :site_b) == b
+    assert Volt.Cache.get(path, 1) == nil
+    Volt.Cache.evict_file(path, :site_a)
+    assert Volt.Cache.get_file(path, :site_a) == nil
+    assert Volt.Cache.get_file(path <> "?import", :site_a) == nil
+    assert Volt.Cache.get_file(path, :site_b) == b
+    Volt.Cache.clear_session(:site_b)
+    assert Volt.Cache.get_file(path, :site_b) == nil
+  end
+
   test "get returns nil on miss" do
     assert Volt.Cache.get("/app.ts", 12345) == nil
   end
diff --git a/test/volt/chunk_graph_test.exs b/test/volt/chunk_graph_test.exs
index 8dcbc43..49342a0 100644
--- a/test/volt/chunk_graph_test.exs
+++ b/test/volt/chunk_graph_test.exs
@@ -135,28 +135,27 @@ defmodule Volt.ChunkGraphTest do
     end
 
     test "records static and dynamic chunk links" do
+      main = Path.expand("app/main.ts")
+      static_vendor = Path.expand("app/static-vendor.ts")
+      lazy = Path.expand("app/lazy.ts")
+
       modules = [
-        {"/app/main.ts", "main.ts", ""},
-        {"/app/static-vendor.ts", "static-vendor.ts", ""},
-        {"/app/lazy.ts", "lazy.ts", ""}
+        {main, "main.ts", ""},
+        {static_vendor, "static-vendor.ts", ""},
+        {lazy, "lazy.ts", ""}
       ]
 
       dep_map = %{
-        "/app/main.ts" => %{
-          static: ["/app/static-vendor.ts"],
-          dynamic: ["/app/lazy.ts"]
-        },
-        "/app/static-vendor.ts" => %{static: [], dynamic: []},
-        "/app/lazy.ts" => %{static: [], dynamic: []}
+        main => %{static: [static_vendor], dynamic: [lazy]},
+        static_vendor => %{static: [], dynamic: []},
+        lazy => %{static: [], dynamic: []}
       }
 
       graph =
-        ChunkGraph.build("/app/main.ts", modules, dep_map,
-          manual_chunks: %{"vendor" => ["/app/static-vendor.ts"]}
-        )
+        ChunkGraph.build(main, modules, dep_map, manual_chunks: %{"vendor" => [static_vendor]})
 
       assert graph.chunks["entry"].imports == ["vendor"]
-      assert graph.chunks["entry"].dynamic_imports == [graph.module_to_chunk["/app/lazy.ts"]]
+      assert graph.chunks["entry"].dynamic_imports == [graph.module_to_chunk[lazy]]
     end
 
     test "module_to_chunk maps dynamic entry to async chunk" do
@@ -232,37 +231,33 @@ defmodule Volt.ChunkGraphTest do
     end
 
     test "path patterns match by directory prefix" do
+      main = Path.expand("app/main.ts")
+      button = Path.expand("app/src/components/Button.ts")
+      modal = Path.expand("app/src/components/Modal.ts")
+      utils = Path.expand("app/src/utils.ts")
+
       modules = [
-        {"/app/main.ts", "main.ts", ""},
-        {"/app/src/components/Button.ts", "Button.ts", ""},
-        {"/app/src/components/Modal.ts", "Modal.ts", ""},
-        {"/app/src/utils.ts", "utils.ts", ""}
+        {main, "main.ts", ""},
+        {button, "Button.ts", ""},
+        {modal, "Modal.ts", ""},
+        {utils, "utils.ts", ""}
       ]
 
       dep_map = %{
-        "/app/main.ts" => %{
-          static: [
-            "/app/src/components/Button.ts",
-            "/app/src/components/Modal.ts",
-            "/app/src/utils.ts"
-          ],
-          dynamic: []
-        },
-        "/app/src/components/Button.ts" => %{static: [], dynamic: []},
-        "/app/src/components/Modal.ts" => %{static: [], dynamic: []},
-        "/app/src/utils.ts" => %{static: [], dynamic: []}
+        main => %{static: [button, modal, utils], dynamic: []},
+        button => %{static: [], dynamic: []},
+        modal => %{static: [], dynamic: []},
+        utils => %{static: [], dynamic: []}
       }
 
       graph =
-        ChunkGraph.build("/app/main.ts", modules, dep_map,
-          manual_chunks: %{"ui" => ["/app/src/components"]}
-        )
+        ChunkGraph.build(main, modules, dep_map, manual_chunks: %{"ui" => [Path.dirname(button)]})
 
       assert graph.chunks["ui"].type == :manual
-      assert "/app/src/components/Button.ts" in graph.chunks["ui"].modules
-      assert "/app/src/components/Modal.ts" in graph.chunks["ui"].modules
+      assert button in graph.chunks["ui"].modules
+      assert modal in graph.chunks["ui"].modules
 
-      refute "/app/src/utils.ts" in graph.chunks["ui"].modules
+      refute utils in graph.chunks["ui"].modules
     end
 
     test "manual chunks coexist with dynamic imports" do
diff --git a/test/volt/client/fixtures/document.browser.test.ts b/test/volt/client/fixtures/document.browser.test.ts
new file mode 100644
index 0000000..58bfd25
--- /dev/null
+++ b/test/volt/client/fixtures/document.browser.test.ts
@@ -0,0 +1,80 @@
+import { test, expect, beforeEach } from 'volt:test'
+import { morphDocument } from 'volt:client/document'
+
+function page(body: string, head = '') {
+  return new DOMParser().parseFromString(
+    `<!DOCTYPE html><html><head><title>Next</title>${head}</head><body>${body}</body></html>`,
+    'text/html'
+  )
+}
+
+beforeEach(() => {
+  document.head.querySelectorAll('link[data-test], style[data-test]').forEach((node) => node.remove())
+  document.body.innerHTML = '<main><h1 id="title">Hello</h1><p id="text">first</p></main>'
+})
+
+test('patches changed text and keeps the elements that did not change', () => {
+  const title = document.getElementById('title')
+  const text = document.getElementById('text')
+
+  expect(morphDocument(page('<main><h1 id="title">Hello</h1><p id="text">second</p></main>'), '')).toBe(
+    true
+  )
+
+  expect(document.getElementById('text')?.textContent).toBe('second')
+  expect(document.getElementById('title')).toBe(title)
+  expect(document.getElementById('text')).toBe(text)
+  expect(document.title).toBe('Next')
+})
+
+test('patches attributes such as classes', () => {
+  expect(morphDocument(page('<main class="wide"><h1 id="title">Hello</h1></main>'), '')).toBe(true)
+
+  expect(document.querySelector('main')?.className).toBe('wide')
+  expect(document.getElementById('text')).toBeNull()
+})
+
+test('refuses when the scripts the page runs differ', () => {
+  const next = page('<main><p id="text">second</p></main><script>window.changed = true</script>')
+
+  expect(morphDocument(next, '')).toBe(false)
+  expect(document.getElementById('text')?.textContent).toBe('first')
+})
+
+test('patches data blocks, which the browser does not run', () => {
+  const next = page('<main><script type="application/json" id="data">{"a":1}</script></main>')
+
+  expect(morphDocument(next, '')).toBe(true)
+  expect(document.getElementById('data')?.textContent).toBe('{"a":1}')
+})
+
+test('refuses when the stylesheets differ', () => {
+  const next = page('<main></main>', '<style data-test>.a { color: red }</style>')
+
+  expect(morphDocument(next, '')).toBe(false)
+})
+
+test('leaves elements owned by client code alone', () => {
+  document.body.innerHTML =
+    '<p id="text">first</p><div data-island="counter" data-props="{}" data-mounted><b>3 clicks</b></div>'
+
+  const island = document.querySelector('[data-island]')
+
+  const next = page('<p id="text">second</p><div data-island="counter" data-props="{}"></div>')
+
+  expect(morphDocument(next, '[data-island]')).toBe(true)
+  expect(document.getElementById('text')?.textContent).toBe('second')
+  expect(document.querySelector('[data-island]')).toBe(island)
+  expect(island?.innerHTML).toBe('<b>3 clicks</b>')
+  expect(island?.hasAttribute('data-mounted')).toBe(true)
+})
+
+test('refuses when what the server renders for an owned element differs', () => {
+  document.body.innerHTML = '<div data-island="counter" data-props="{&quot;start&quot;:1}"></div>'
+
+  const changed = page('<div data-island="counter" data-props="{&quot;start&quot;:2}"></div>')
+  const added = page('<div data-island="counter" data-props="{&quot;start&quot;:1}"></div><div data-island="other"></div>')
+
+  expect(morphDocument(changed, '[data-island]')).toBe(false)
+  expect(morphDocument(added, '[data-island]')).toBe(false)
+})
diff --git a/test/volt/client/fixtures/overlay.browser.test.ts b/test/volt/client/fixtures/overlay.browser.test.ts
index 4890a93..3426eac 100644
--- a/test/volt/client/fixtures/overlay.browser.test.ts
+++ b/test/volt/client/fixtures/overlay.browser.test.ts
@@ -1,37 +1,53 @@
 import { test, expect, beforeEach } from 'volt:test'
-import { renderErrorOverlay } from 'volt:client/overlay'
+import { clearErrorOverlay, renderErrorOverlay } from 'volt:client/overlay'
 
 beforeEach(() => {
   document.body.innerHTML = ''
 })
 
-test('renders build errors into the browser overlay', () => {
-  renderErrorOverlay('syntax exploded', { title: 'Compile failed' })
+function overlayText() {
+  return document.querySelector('volt-error-overlay')?.shadowRoot?.textContent ?? ''
+}
 
-  const overlay = document.getElementById('volt-error-overlay')
+test('renders build errors into the browser overlay', () => {
+  renderErrorOverlay([
+    { title: 'Compile failed', message: 'syntax exploded', file: 'app.ts', line: 3 }
+  ])
 
-  expect(overlay).toBeDefined()
-  expect(overlay?.textContent).toContain('[Volt] Compile failed:')
-  expect(overlay?.textContent).toContain('syntax exploded')
+  expect(overlayText()).toContain('Compile failed')
+  expect(overlayText()).toContain('syntax exploded')
+  expect(overlayText()).toContain('app.ts:3')
 })
 
-test('updates an existing browser overlay instead of appending duplicates', () => {
-  renderErrorOverlay('first failure')
-  renderErrorOverlay({ message: 'second failure' })
+test('replaces an existing browser overlay instead of appending duplicates', () => {
+  renderErrorOverlay([{ title: 'Build error', message: 'first failure' }])
+  renderErrorOverlay([{ title: 'Build error', message: 'second failure' }])
+
+  expect(document.querySelectorAll('volt-error-overlay')).toHaveLength(1)
+  expect(overlayText()).toContain('second failure')
+  expect(overlayText()).not.toContain('first failure')
+})
 
-  const overlays = document.querySelectorAll('#volt-error-overlay')
+test('counts errors with different titles under one heading', () => {
+  renderErrorOverlay([
+    { title: 'Build error', message: 'first failure' },
+    { title: 'Render error', message: 'second failure' }
+  ])
 
-  expect(overlays).toHaveLength(1)
-  expect(overlays[0]?.textContent).toContain('second failure')
+  expect(overlayText()).toContain('Errors · 2')
 })
 
-test('dismissible browser overlays remove themselves when clicked', () => {
-  renderErrorOverlay('dismiss me', { dismissible: true })
+test('removes the browser overlay when errors clear or the backdrop is clicked', () => {
+  renderErrorOverlay([{ title: 'Build error', message: 'dismiss me' }])
 
-  const overlay = document.getElementById('volt-error-overlay')
-  expect(overlay).toBeDefined()
+  const backdrop = document
+    .querySelector('volt-error-overlay')
+    ?.shadowRoot?.querySelector('.backdrop')
 
-  overlay?.click()
+  backdrop?.dispatchEvent(new MouseEvent('click', { bubbles: true, composed: true }))
+  expect(document.querySelector('volt-error-overlay')).toBeNull()
 
-  expect(document.getElementById('volt-error-overlay')).toBeNull()
+  renderErrorOverlay([{ title: 'Build error', message: 'clear me' }])
+  clearErrorOverlay()
+  expect(document.querySelector('volt-error-overlay')).toBeNull()
 })
diff --git a/test/volt/client/fixtures/styles.browser.test.ts b/test/volt/client/fixtures/styles.browser.test.ts
index 1f39cc2..5c2d233 100644
--- a/test/volt/client/fixtures/styles.browser.test.ts
+++ b/test/volt/client/fixtures/styles.browser.test.ts
@@ -26,15 +26,35 @@ test('removes style tags by Volt style id', () => {
   expect(document.head.querySelector('style[data-volt-id="/assets/remove.css?import"]')).toBeNull()
 })
 
-test('refreshes matching stylesheet links for CSS updates', async () => {
+test('replaces matching stylesheet links once the refreshed stylesheet settles', async () => {
   const link = document.createElement('link')
   link.rel = 'stylesheet'
-  link.href = 'https://example.test/assets/site.css'
+  link.href = new URL('./assets/site.css', location.href).href
   link.dataset.testStyle = 'true'
   document.head.appendChild(link)
 
   await updateStyles('/assets/site.css')
 
-  expect(link.href).toContain('/assets/site.css')
-  expect(link.href).toContain('t=')
+  const links = document.head.querySelectorAll<HTMLLinkElement>('link[data-test-style]')
+
+  expect(links).toHaveLength(1)
+  expect(links[0]).not.toBe(link)
+  expect(links[0]?.href).toContain('/assets/site.css')
+  expect(links[0]?.href).toContain('t=')
+})
+
+test('keeps the current stylesheet applied until the refreshed one settles', () => {
+  const link = document.createElement('link')
+  link.rel = 'stylesheet'
+  link.href = new URL('./assets/pending.css', location.href).href
+  link.dataset.testStyle = 'true'
+  document.head.appendChild(link)
+
+  void updateStyles('/assets/pending.css')
+
+  const links = document.head.querySelectorAll<HTMLLinkElement>('link[data-test-style]')
+
+  expect(links).toHaveLength(2)
+  expect(links[0]).toBe(link)
+  expect(links[1]?.href).toContain('t=')
 })
diff --git a/test/volt/config/tailwind_test.exs b/test/volt/config/tailwind_test.exs
new file mode 100644
index 0000000..258c1fc
--- /dev/null
+++ b/test/volt/config/tailwind_test.exs
@@ -0,0 +1,43 @@
+defmodule Volt.Config.TailwindTest do
+  use ExUnit.Case, async: true
+
+  test "normalizes disabled and default-enabled configuration" do
+    for value <- [false, nil, true] do
+      assert %Volt.Config.Tailwind{sources: [], css: nil} = Volt.Config.Tailwind.new(value)
+    end
+
+    refute Volt.Config.Tailwind.enabled?(false)
+    refute Volt.Config.Tailwind.enabled?(nil)
+    assert Volt.Config.Tailwind.enabled?(true)
+  end
+
+  test "normalizes a configured root" do
+    root =
+      Volt.Config.Tailwind.new(
+        css: "assets/styles.css",
+        name: "site",
+        dev_url: "/custom/site.css",
+        sources: [%{base: "lib", pattern: "**/*.heex"}]
+      )
+
+    assert root.css == Path.expand("assets/styles.css")
+    assert root.name == "site"
+    assert root.dev_url == "/custom/site.css"
+    assert root.sources == [%{base: "lib", pattern: "**/*.heex"}]
+  end
+
+  test "derives identity from the CSS input" do
+    root = Volt.Config.Tailwind.new(css: "assets/styles.css")
+
+    assert root.name == "styles"
+    assert root.dev_url == "/assets/css/styles.css"
+  end
+
+  test "supports Tailwind defaults without a CSS input" do
+    root = Volt.Config.Tailwind.new([])
+
+    assert root.css == nil
+    assert root.name == "app"
+    assert root.dev_url == "/assets/css/app.css"
+  end
+end
diff --git a/test/volt/config_test.exs b/test/volt/config_test.exs
index 21f7f04..afc1edb 100644
--- a/test/volt/config_test.exs
+++ b/test/volt/config_test.exs
@@ -124,6 +124,12 @@ defmodule Volt.ConfigTest do
       refute Volt.Config.server().watch
     end
 
+    test "watcher ignore patterns are configurable" do
+      Application.put_env(:volt, :server, watch_ignored: ["**/.generated/**"])
+
+      assert Volt.Config.server().watch_ignored == ["**/.generated/**"]
+    end
+
     test "profile server config takes precedence over global :server" do
       Application.put_env(:volt, :my_app,
         entry: "my_app/js/app.ts",
diff --git a/test/volt/css/asset_url_rewriter_test.exs b/test/volt/css/asset_url_rewriter_test.exs
index 7812768..cf17bb6 100644
--- a/test/volt/css/asset_url_rewriter_test.exs
+++ b/test/volt/css/asset_url_rewriter_test.exs
@@ -1,7 +1,7 @@
 defmodule Volt.CSS.AssetURLRewriterTest do
   use ExUnit.Case, async: true
 
-  @fixture_dir Path.join(System.tmp_dir!(), "volt-css-asset-url-rewriter-test")
+  @fixture_dir Path.expand("volt-css-asset-url-rewriter-test", System.tmp_dir!())
   @outdir Path.join(@fixture_dir, "dist")
 
   setup do
@@ -14,6 +14,23 @@ defmodule Volt.CSS.AssetURLRewriterTest do
     :ok
   end
 
+  @tag :tmp_dir
+  test "prepares rewritten URLs and binary artifacts without copying files", %{tmp_dir: root} do
+    File.write!(Path.join(root, "icon.svg"), "<svg/>")
+    css = ~s|.a { background: url('./icon.svg?v=1#mark') } .b { background: url('./icon.svg') }|
+
+    assert {:ok, result} =
+             Volt.CSS.AssetURLRewriter.prepare(css, Path.join(root, "app.css"),
+               prefix: "https://cdn.example/assets",
+               root: root
+             )
+
+    assert [%Volt.Builder.Artifact{file: file, content: "<svg/>"}] = result.artifacts
+    assert [%Volt.Builder.Asset{src: "icon.svg", file: ^file}] = result.assets
+    assert result.code =~ "https://cdn.example/assets/#{file}?v=1#mark"
+    assert File.ls!(root) == ["icon.svg"]
+  end
+
   test "rewrites relative url nodes through hashed assets" do
     File.write!(Path.join(@fixture_dir, "src/icons/logo.svg"), "<svg></svg>")
     source_path = Path.join(@fixture_dir, "src/app.css")
diff --git a/test/volt/css/dependencies_test.exs b/test/volt/css/dependencies_test.exs
index 9143f4e..80c0f4d 100644
--- a/test/volt/css/dependencies_test.exs
+++ b/test/volt/css/dependencies_test.exs
@@ -1,7 +1,7 @@
 defmodule Volt.CSS.DependenciesTest do
   use ExUnit.Case, async: true
 
-  @root Path.join(System.tmp_dir!(), "volt-css-dependencies-test")
+  @root Path.expand("volt-css-dependencies-test", System.tmp_dir!())
 
   setup do
     File.rm_rf!(@root)
diff --git a/test/volt/css/imports_test.exs b/test/volt/css/imports_test.exs
new file mode 100644
index 0000000..54ccd33
--- /dev/null
+++ b/test/volt/css/imports_test.exs
@@ -0,0 +1,50 @@
+defmodule Volt.CSS.ImportsTest do
+  use ExUnit.Case, async: true
+
+  @moduletag :tmp_dir
+
+  test "nested imports retain asset origins without copying files", %{tmp_dir: root} do
+    File.mkdir_p!(Path.join(root, "nested/deep"))
+
+    File.write!(
+      Path.join(root, "nested/theme.css"),
+      "@import './deep/fonts.css'; .logo { background: url('./logo.svg?v=1#mark') }"
+    )
+
+    File.write!(
+      Path.join(root, "nested/deep/fonts.css"),
+      "@font-face { font-family: Test; src: url('./font.woff2') }"
+    )
+
+    assert {:ok, css} =
+             Volt.CSS.Imports.inline(
+               "@import './nested/theme.css';",
+               Path.join(root, "app.css"),
+               []
+             )
+
+    assert css =~ "nested/logo.svg?v=1#mark"
+    assert css =~ "nested/deep/font.woff2"
+    refute css =~ "@import"
+  end
+
+  test "package imports rebase relative to the package stylesheet", %{tmp_dir: root} do
+    package = Path.join(root, "node_modules/theme")
+    File.mkdir_p!(package)
+
+    File.write!(
+      Path.join(package, "package.json"),
+      ~s({"name":"theme","exports":{".":"./index.css"}})
+    )
+
+    File.write!(Path.join(package, "index.css"), ".theme { background: url('./logo.svg') }")
+
+    assert {:ok, css} =
+             Volt.CSS.Imports.inline("@import 'theme';", Path.join(root, "app.css"),
+               node_modules: Path.join(root, "node_modules")
+             )
+
+    assert css =~ "node_modules/theme/logo.svg"
+    refute css =~ "@import"
+  end
+end
diff --git a/test/volt/dev/assets_test.exs b/test/volt/dev/assets_test.exs
new file mode 100644
index 0000000..14e8cb4
--- /dev/null
+++ b/test/volt/dev/assets_test.exs
@@ -0,0 +1,49 @@
+defmodule Volt.Dev.AssetsTest do
+  use ExUnit.Case, async: false
+
+  @tag :tmp_dir
+  test "serves only resolved stylesheet assets in the owning session", %{tmp_dir: root} do
+    assets = Path.join(root, "assets")
+    package = Path.join(root, "node_modules/font")
+    File.mkdir_p!(assets)
+    File.mkdir_p!(package)
+    font = Path.join(package, "font.woff2")
+    File.write!(font, "font-content")
+
+    File.write!(
+      Path.join(assets, "style.css"),
+      "@font-face { src: url('../node_modules/font/font.woff2?v=1#font'); }"
+    )
+
+    first = Volt.DevServer.init(root: assets, session: make_ref(), watch: true)
+    second = Volt.DevServer.init(root: assets, session: make_ref(), watch: true)
+
+    on_exit(fn ->
+      Volt.Dev.stop(first.session)
+      Volt.Dev.stop(second.session)
+    end)
+
+    css = Plug.Test.conn(:get, "/assets/style.css") |> Volt.DevServer.call(first)
+    assert css.status == 200
+    assert css.resp_body =~ "/@volt/assets/"
+    assert css.resp_body =~ "?v=1#font"
+    tables = Volt.Dev.tables(first.session)
+    url = Volt.Dev.Assets.register(font, tables)
+    served = Plug.Test.conn(:get, url) |> Volt.DevServer.call(first)
+    assert served.status == 200
+    assert served.resp_body == "font-content"
+    head = Plug.Test.conn(:head, url) |> Volt.DevServer.call(first)
+    assert head.status == 200
+    assert head.resp_body == ""
+    assert (Plug.Test.conn(:get, url) |> Volt.DevServer.call(second)).status == 404
+
+    assert (Plug.Test.conn(:get, "/@volt/assets/arbitrary-path")
+            |> Volt.DevServer.call(first)).status == 404
+
+    owner = tables.owner
+    monitor = Process.monitor(owner)
+    Process.exit(owner, :kill)
+    assert_receive {:DOWN, ^monitor, :process, ^owner, :killed}
+    assert :ets.info(tables.assets) == :undefined
+  end
+end
diff --git a/test/volt/dev/error_test.exs b/test/volt/dev/error_test.exs
new file mode 100644
index 0000000..ccb0de2
--- /dev/null
+++ b/test/volt/dev/error_test.exs
@@ -0,0 +1,116 @@
+defmodule Volt.Dev.ErrorTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.Dev.Error
+
+  @moduletag :tmp_dir
+
+  test "locates diagnostics and frames the source line", %{tmp_dir: tmp_dir} do
+    path = Path.join(tmp_dir, "app.ts")
+    File.write!(path, "const a = 1\nconst b = 2\nconst = ;\nconst c = 3\nconst d = 4\n")
+    {:error, diagnostics} = OXC.parse(File.read!(path), "app.ts")
+
+    assert [%{file: file, line: 3, column: 7, message: message, frame: frame}] =
+             Error.entries(diagnostics, file: path)
+
+    assert file == Path.relative_to_cwd(path)
+    assert message =~ "Unexpected token"
+
+    assert frame == """
+             1 | const a = 1
+             2 | const b = 2
+           > 3 | const = ;
+               |       ^
+             4 | const c = 3\
+           """
+  end
+
+  test "highlights the frame with Lumis when a parser covers the language", %{tmp_dir: tmp_dir} do
+    path = Path.join(tmp_dir, "app.ts")
+    File.write!(path, "/* a\n   comment */\nconst a = 1 < 2\nconst = ;\n")
+    {:error, diagnostics} = OXC.parse(File.read!(path), "app.ts")
+
+    assert [%{frame_html: html}] = Error.entries(diagnostics, file: path)
+    assert html =~ ~s(<span style="color:#ff6b9a">&gt; 4 | </span>)
+    assert html =~ ~s(<span style="color:#6b5b8f">  3 | </span>)
+    assert html =~ ~s(<span style="color: #8b949e;">   comment */</span>)
+    assert html =~ "&lt;"
+    refute html =~ "1 < 2"
+    assert length(String.split(html, "\n")) == 5
+  end
+
+  test "keeps only the plain frame without a parser for the language", %{tmp_dir: tmp_dir} do
+    path = Path.join(tmp_dir, "app.css")
+    File.write!(path, ".a { color: red\n")
+
+    assert [%{frame: "> 1 | .a { color: red" <> _, frame_html: nil}] =
+             Error.entries(%{message: "x", position: {1, 2}}, file: path)
+  end
+
+  test "keeps a diagnostic's own file when it differs from the source path" do
+    diagnostic = %{message: "boom", file: "other.ts", position: {2, 1}, details: "try this"}
+
+    assert [%{file: "other.ts", line: 2, column: 1, hint: "try this", frame: nil}] =
+             Error.entries([diagnostic], file: "app.ts")
+  end
+
+  test "reads Mix compiler diagnostics", %{tmp_dir: tmp_dir} do
+    path = Path.join(tmp_dir, "site.ex")
+    File.write!(path, "defmodule Site do\n  def domain, do: oops()\nend\n")
+
+    diagnostic = %Mix.Task.Compiler.Diagnostic{
+      file: path,
+      source: path,
+      severity: :error,
+      message: "undefined function oops/0",
+      position: {2, 19},
+      compiler_name: "Elixir",
+      details: nil,
+      stacktrace: [{Site, :domain, 0, [file: ~c"site.ex", line: 2]}]
+    }
+
+    assert [
+             %{
+               message: "undefined function oops/0",
+               line: 2,
+               column: 19,
+               frame: frame,
+               stack: stack
+             }
+           ] =
+             Error.entries([diagnostic])
+
+    assert frame =~ "> 2 |   def domain, do: oops()"
+    assert stack =~ "site.ex:2"
+  end
+
+  test "formats a diagnostic's stacktrace" do
+    stacktrace = [{MyApp.Page, :render, 1, [file: ~c"lib/my_app/page.ex", line: 12]}]
+
+    assert [%{stack: "    lib/my_app/page.ex:12: MyApp.Page.render/1\n"}] =
+             Error.entries(%{message: "boom", stacktrace: stacktrace})
+
+    assert [%{stack: nil}] = Error.entries(%{message: "boom", stacktrace: []})
+  end
+
+  test "describes messages, exceptions, and other terms" do
+    assert [
+             %{message: "plain", file: "app.ts", line: nil, frame: nil},
+             %{message: "raised"},
+             %{message: "{:unsupported, \".xyz\"}"}
+           ] =
+             Error.entries(["plain", RuntimeError.exception("raised"), {:unsupported, ".xyz"}],
+               file: "app.ts"
+             )
+  end
+
+  test "titles entries as build errors unless given a title" do
+    assert [%{title: "Build error"}] = Error.entries("boom")
+    assert [%{title: "Render error"}] = Error.entries("boom", title: "Render error")
+  end
+
+  test "entries encode as JSON" do
+    {:error, diagnostics} = OXC.parse("const = ;", "app.ts")
+    assert {:ok, _json} = diagnostics |> Error.entries(file: "app.ts") |> Jason.encode()
+  end
+end
diff --git a/test/volt/dev/session/call_test.exs b/test/volt/dev/session/call_test.exs
new file mode 100644
index 0000000..242a175
--- /dev/null
+++ b/test/volt/dev/session/call_test.exs
@@ -0,0 +1,15 @@
+defmodule Volt.Dev.Session.CallTest do
+  use ExUnit.Case, async: true
+
+  test "a terminated supervisor returns a retryable result" do
+    {:ok, supervisor} = Volt.Dev.Session.Supervisor.start_link([])
+    Supervisor.stop(supervisor)
+    assert {:error, :session_restarting} = Volt.Dev.Session.Supervisor.tables(supervisor)
+    assert {:error, :session_restarting} = Volt.Dev.Session.Supervisor.stylesheet(supervisor)
+  end
+
+  test "unrelated exits and exceptions remain visible" do
+    assert catch_exit(Volt.Dev.Session.Call.run(fn -> exit(:unexpected) end)) == :unexpected
+    assert_raise ArgumentError, fn -> Volt.Dev.Session.Call.run(fn -> raise ArgumentError end) end
+  end
+end
diff --git a/test/volt/dev/session/state_test.exs b/test/volt/dev/session/state_test.exs
new file mode 100644
index 0000000..956d768
--- /dev/null
+++ b/test/volt/dev/session/state_test.exs
@@ -0,0 +1,44 @@
+defmodule Volt.Dev.Session.StateTest do
+  use ExUnit.Case, async: true
+
+  test "graphs use owned tables and reject stale generation handles" do
+    owner = start_supervised!(Volt.Dev.Session.State)
+    tables = Volt.Dev.Session.State.tables(owner)
+    alias Volt.HMR.{ImportGraph, GlobGraph, StyleGraph, ModuleGraph, Boundary}
+    ImportGraph.update("/parent.js", ["./child.js"], tables)
+    GlobGraph.update("/parent.js", ["/pages/*.js"], tables)
+    StyleGraph.update("/app.css", ["/theme.css"], tables)
+    ModuleGraph.update_module("/child.js", "/child.js", "/child.js", [], session: tables)
+
+    ModuleGraph.update_module("/parent.js", "/parent.js", "/parent.js", ["/child.js"],
+      session: tables
+    )
+
+    read = fn path -> if path == "/parent.js", do: "import.meta.hot.accept()", else: "" end
+    assert Boundary.find_boundary("/child.js", read, tables) == {:ok, "/parent.js"}
+    assert GlobGraph.dependents("/pages/page.js", tables) == ["/parent.js"]
+    assert StyleGraph.dependents("/theme.css", tables) == ["/app.css"]
+    assert :ets.info(tables.modules, :owner) == owner
+    stop_supervised!(Volt.Dev.Session.State)
+    assert_raise ArgumentError, fn -> ImportGraph.update("/parent.js", [], tables) end
+    assert_raise ArgumentError, fn -> GlobGraph.update("/parent.js", [], tables) end
+    assert_raise ArgumentError, fn -> StyleGraph.update("/app.css", [], tables) end
+    assert_raise ArgumentError, fn -> ModuleGraph.get_by_id("/child.js", tables) end
+  end
+
+  test "forced owner termination destroys tables without a terminate callback" do
+    {:ok, owner} = Volt.Dev.Session.State.start_link([])
+    Process.unlink(owner)
+    tables = Volt.Dev.Session.State.tables(owner)
+    :ets.insert(tables.cache, {:entry, "old"})
+    monitor = Process.monitor(owner)
+    Process.exit(owner, :kill)
+    assert_receive {:DOWN, ^monitor, :process, ^owner, :killed}
+
+    for table <- [tables.cache, tables.imports, tables.globs, tables.styles, tables.modules] do
+      assert :ets.info(table) == :undefined
+    end
+
+    assert_raise ArgumentError, fn -> :ets.insert(tables.cache, {:entry, "stale write"}) end
+  end
+end
diff --git a/test/volt/dev/session/supervisor_test.exs b/test/volt/dev/session/supervisor_test.exs
new file mode 100644
index 0000000..194fb90
--- /dev/null
+++ b/test/volt/dev/session/supervisor_test.exs
@@ -0,0 +1,135 @@
+defmodule Volt.Dev.Session.SupervisorTest do
+  use ExUnit.Case, async: true
+
+  defmodule Witness do
+    use GenServer
+    def start_link(parent), do: GenServer.start_link(__MODULE__, parent)
+
+    def init(parent) do
+      send(parent, {:dependent_started, self()})
+      {:ok, parent}
+    end
+  end
+
+  @tag :tmp_dir
+  test "Tailwind compilation stays inside the subtree", %{tmp_dir: root} do
+    identity = make_ref()
+    css = Path.join(root, "app.css")
+    File.write!(css, "@tailwind utilities;")
+    count = Registry.count(Volt.Tailwind.Registry)
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: identity,
+         watcher: [
+           root: root,
+           name: nil,
+           tailwind: true,
+           tailwind_css: css,
+           tailwind_sources: [],
+           tailwind_outdir: Path.join(root, "output")
+         ]}
+      )
+
+    children = Supervisor.which_children(supervisor)
+    {_, worker, _, _} = Enum.find(children, fn {id, _, _, _} -> id == Volt.Tailwind.Worker end)
+    {_, runtime, _, _} = Enum.find(children, fn {id, _, _, _} -> id == Volt.Tailwind.Runtime end)
+    assert :sys.get_state(worker).last_css
+    refute File.exists?(Path.join(root, "output"))
+    tables = Volt.Dev.Session.Supervisor.tables(supervisor)
+    assert tables.stylesheet_worker == worker
+    assert :sys.get_state(runtime).pid
+    assert Registry.count(Volt.Tailwind.Registry) == count
+    stop_supervised!(Volt.Dev.Session.Supervisor)
+    refute Process.alive?(worker)
+    refute Process.alive?(runtime)
+  end
+
+  test "session subtree owns its lazy Tailwind runtime", %{test: test} do
+    identity = {test, make_ref()}
+    root = System.tmp_dir!()
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: identity, watcher: [root: root, name: nil, tailwind: false]}
+      )
+
+    {_, runtime, _, _} =
+      Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+        id == Volt.Tailwind.Runtime
+      end)
+
+    assert :sys.get_state(runtime) == nil
+    assert {:ok, _} = Volt.Tailwind.Runtime.call("@tailwind utilities;", ["flex"], root, runtime)
+    compiler = :sys.get_state(runtime).pid
+    monitor = Process.monitor(compiler)
+    stop_supervised!(Volt.Dev.Session.Supervisor)
+    assert_receive {:DOWN, ^monitor, :process, ^compiler, _}
+    refute Process.alive?(runtime)
+  end
+
+  test "real watcher restarts with replacement table handles", %{test: test} do
+    root = Path.join(System.tmp_dir!(), "volt-owned-#{System.unique_integer([:positive])}")
+    File.mkdir_p!(root)
+    on_exit(fn -> File.rm_rf!(root) end)
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: {test, make_ref()}, watcher: [root: root, name: nil, tailwind: false]}
+      )
+
+    children = Supervisor.which_children(supervisor)
+    {_, owner, _, _} = Enum.find(children, fn {id, _, _, _} -> id == Volt.Dev.Session.State end)
+
+    {_, watcher, _, _} =
+      Enum.find(children, fn {id, _, _, _} -> id == Volt.Dev.Session.Watcher end)
+
+    tables = Volt.Dev.Session.State.tables(owner)
+    assert :sys.get_state(watcher).tables == tables
+    Volt.Cache.put("/app.js", 1, %Volt.DevServer.CacheEntry{code: "owned"}, tables)
+    assert Volt.Cache.get_file("/app.js", tables).code == "owned"
+    monitor = Process.monitor(watcher)
+    Process.exit(owner, :kill)
+    assert_receive {:DOWN, ^monitor, :process, ^watcher, :shutdown}
+    children = Supervisor.which_children(supervisor)
+
+    {_, replacement, _, _} =
+      Enum.find(children, fn {id, _, _, _} -> id == Volt.Dev.Session.Watcher end)
+
+    refute :sys.get_state(replacement).tables.generation == tables.generation
+
+    assert_raise ArgumentError, fn ->
+      Volt.Cache.put("/app.js", 1, %Volt.DevServer.CacheEntry{}, tables)
+    end
+  end
+
+  test "state owner failure restarts dependent children with a new generation" do
+    supervisor = start_supervised!({Volt.Dev.Session.Supervisor, children: [{Witness, self()}]})
+    assert_receive {:dependent_started, first}
+
+    {_, owner, _, _} =
+      Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+        id == Volt.Dev.Session.State
+      end)
+
+    old = Volt.Dev.Session.State.tables(owner)
+    monitor = Process.monitor(first)
+    Process.exit(owner, :kill)
+    assert_receive {:DOWN, ^monitor, :process, ^first, :shutdown}
+    assert_receive {:dependent_started, second}
+    refute first == second
+
+    {_, replacement, _, _} =
+      Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+        id == Volt.Dev.Session.State
+      end)
+
+    new = Volt.Dev.Session.State.tables(replacement)
+    refute old.generation == new.generation
+    assert :ets.info(old.cache) == :undefined
+    assert :ets.info(new.cache, :owner) == replacement
+  end
+end
diff --git a/test/volt/dev_server/basic_test.exs b/test/volt/dev_server/basic_test.exs
index 47294d4..019b8d8 100644
--- a/test/volt/dev_server/basic_test.exs
+++ b/test/volt/dev_server/basic_test.exs
@@ -26,7 +26,7 @@ defmodule Volt.DevServer.BasicTest do
 
       root = Path.join(@fixture_dir, "src")
       opts = Volt.DevServer.init(root: root, prefix: "/assets", watch: true)
-      key = {:watcher, :default, Path.expand(root)}
+      key = {:session, opts.session}
 
       assert [] = Registry.lookup(Volt.Dev.WatcherRegistry, key)
 
@@ -35,10 +35,66 @@ defmodule Volt.DevServer.BasicTest do
       assert [{pid, _}] = Registry.lookup(Volt.Dev.WatcherRegistry, key)
       assert Process.alive?(pid)
 
+      assert %Volt.Dev.Session.Tables{} = Volt.Dev.tables(opts.session)
+      on_exit(fn -> Volt.Dev.stop(opts.session) end)
+    end
+
+    test "normalizes configured Tailwind root into watcher options" do
+      previous = Application.get_env(:volt, :tailwind)
+      css = Path.join(@fixture_dir, "src/site.css")
+
+      Application.put_env(:volt, :tailwind,
+        css: css,
+        name: "site",
+        dev_url: "/assets/css/site.css",
+        sources: [%{base: @fixture_dir, pattern: "**/*.html"}]
+      )
+
       on_exit(fn ->
-        if Process.alive?(pid),
-          do: DynamicSupervisor.terminate_child(Volt.Dev.WatcherSupervisor, pid)
+        if previous,
+          do: Application.put_env(:volt, :tailwind, previous),
+          else: Application.delete_env(:volt, :tailwind)
       end)
+
+      opts =
+        Volt.DevServer.init(
+          root: Path.join(@fixture_dir, "src"),
+          prefix: "/assets",
+          watch: true
+        )
+
+      assert opts.watcher_opts[:tailwind]
+      assert opts.watcher_opts[:tailwind_css] == Path.expand(css)
+      assert opts.watcher_opts[:tailwind_name] == "site"
+
+      assert opts.watcher_opts[:tailwind_sources] == [
+               %{base: @fixture_dir, pattern: "**/*.html"}
+             ]
+
+      assert opts.watcher_opts[:tailwind_url] == "/assets/css/site.css"
+      assert opts.watcher_opts[:tailwind_key] == {:profile, :default, Path.expand(css)}
+    end
+
+    @tag :tmp_dir
+    test "explains a conflicting watcher instead of answering a bare 503", %{tmp_dir: root} do
+      assets = Path.join(root, "assets")
+      File.mkdir_p!(assets)
+      File.write!(Path.join(assets, "app.ts"), "export const x = 1")
+
+      config = Volt.DevServer.init(root: assets, watch: true)
+      on_exit(fn -> Volt.Dev.stop(config.session) end)
+
+      conflicting = Keyword.put(config.watcher_opts, :watch_dirs, [root])
+      assert {:ok, _watcher} = Volt.Dev.start(conflicting)
+
+      log =
+        ExUnit.CaptureLog.capture_log(fn ->
+          conn = Plug.Test.conn(:get, "/assets/app.ts") |> Volt.DevServer.call(config)
+          assert conn.status == 503
+          assert conn.resp_body =~ "Mix.Tasks.Volt.Dev"
+        end)
+
+      assert log =~ "a Volt watcher is already running"
     end
 
     test "passes through non-asset requests for downstream HTML plugs" do
@@ -135,8 +191,15 @@ defmodule Volt.DevServer.BasicTest do
 
       assert vendor_conn.status == 200
 
-      assert [[_, chunk_path]] =
-               Regex.scan(~r{from "\./(chunks/[^"']+\.js)"}, vendor_conn.resp_body)
+      # Shared chunks carry the importer's browser hash, so a module reached from
+      # both application code and another pre-bundle stays a single instance.
+      [_, browser_hash] = String.split(vendor_url, "?v=")
+
+      assert [[_, chunk_path, ^browser_hash]] =
+               Regex.scan(
+                 ~r{from "\./(chunks/[^"'?]+\.js)\?v=([a-f0-9]+)"},
+                 vendor_conn.resp_body
+               )
 
       chunk_conn =
         call_dev_server("/@vendor/#{chunk_path}",
@@ -174,6 +237,69 @@ defmodule Volt.DevServer.BasicTest do
       assert stale_conn.status == 504
       assert stale_conn.resp_body =~ "outdated optimized dependency"
     end
+
+    test "gives a package that changed in place a new URL once it is bundled again" do
+      package = Path.join(@fixture_dir, "node_modules/linked-lib")
+      File.mkdir_p!(package)
+
+      File.write!(
+        Path.join(package, "package.json"),
+        Jason.encode!(%{"name" => "linked-lib", "main" => "index.js"})
+      )
+
+      File.write!(Path.join(package, "index.js"), "export const version = 1")
+
+      File.write!(
+        Path.join(@fixture_dir, "src/app.ts"),
+        "import { version } from 'linked-lib'\nconsole.log(version)"
+      )
+
+      Volt.Dev.Prebundled.forget()
+      first = call_dev_server("/assets/app.ts")
+      assert [first_url] = Regex.run(~r(/@vendor/linked-lib\.js\?v=[a-f0-9]+), first.resp_body)
+      assert call_dev_server(first_url).resp_body =~ "version = 1"
+
+      File.write!(Path.join(package, "index.js"), "export const version = 2")
+      # What the watcher does when a linked package changes.
+      Volt.Dev.Prebundled.forget()
+
+      # The application module is unchanged, yet imports the new URL.
+      second = call_dev_server("/assets/app.ts")
+      assert [second_url] = Regex.run(~r(/@vendor/linked-lib\.js\?v=[a-f0-9]+), second.resp_body)
+      refute second_url == first_url
+      assert call_dev_server(second_url).resp_body =~ "version = 2"
+      assert call_dev_server(first_url).status == 504
+    end
+
+    test "serves unchanged application modules with new vendor URLs after the lockfile changes" do
+      package = Path.join(@fixture_dir, "node_modules/locked-lib")
+      File.mkdir_p!(package)
+
+      File.write!(
+        Path.join(package, "package.json"),
+        Jason.encode!(%{"name" => "locked-lib", "main" => "index.js"})
+      )
+
+      File.write!(Path.join(package, "index.js"), "export const value = 1")
+
+      File.write!(
+        Path.join(@fixture_dir, "src/app.ts"),
+        "import { value } from 'locked-lib'\nconsole.log(value)"
+      )
+
+      lockfile = Path.join(@fixture_dir, "npm.lock")
+      File.write!(lockfile, ~s({"lockfileVersion":1,"packages":{}}))
+      first = call_dev_server("/assets/app.ts")
+      assert [first_url] = Regex.run(~r(/@vendor/locked-lib\.js\?v=[a-f0-9]+), first.resp_body)
+
+      File.write!(lockfile, ~s({"lockfileVersion":1,"packages":{"locked-lib":{}}}))
+      File.touch!(lockfile, System.os_time(:second) + 2)
+
+      second = call_dev_server("/assets/app.ts")
+      assert [second_url] = Regex.run(~r(/@vendor/locked-lib\.js\?v=[a-f0-9]+), second.resp_body)
+      refute second_url == first_url
+      assert call_dev_server(second_url).status == 200
+    end
   end
 
   describe "TypeScript files" do
diff --git a/test/volt/dev_server/import_rewriting_test.exs b/test/volt/dev_server/import_rewriting_test.exs
index 6a95b0a..42df997 100644
--- a/test/volt/dev_server/import_rewriting_test.exs
+++ b/test/volt/dev_server/import_rewriting_test.exs
@@ -1,6 +1,116 @@
 defmodule Volt.DevServer.ImportRewritingTest do
   use Volt.TestSupport.DevServerCase
 
+  defmodule VirtualAbsolute do
+    @behaviour Volt.Plugin
+    def name, do: "virtual-absolute"
+
+    def load("fixture:entry", root: root),
+      do:
+        {:ok,
+         "import value from #{Jason.encode!(Path.join(root, "value.ts"))}; console.log(value);"}
+
+    def load(_, _), do: nil
+  end
+
+  @tag :tmp_dir
+  test "virtual entry absolute filesystem imports become served URLs", %{tmp_dir: root} do
+    File.write!(Path.join(root, "value.ts"), "export default 42")
+
+    config =
+      Volt.DevServer.init(root: root, watch: false, plugins: [{VirtualAbsolute, root: root}])
+
+    conn = Plug.Test.conn(:get, "/@volt/virtual/fixture:entry") |> Volt.DevServer.call(config)
+    assert conn.status == 200
+    assert conn.resp_body =~ "from \"/assets/value.ts\""
+    refute conn.resp_body =~ Path.join(root, "value.ts")
+  end
+
+  describe "CommonJS interop" do
+    test "serves a local UMD module as an ES module with a default export" do
+      File.mkdir_p!(Path.join(@fixture_dir, "src/vendor"))
+
+      File.write!(Path.join(@fixture_dir, "src/vendor/topbar.js"), """
+      (function (window, document) {
+        var topbar = { show: function () {} };
+        if (typeof module === "object" && typeof module.exports === "object") {
+          module.exports = topbar;
+        } else {
+          this.topbar = topbar;
+        }
+      }.call(this, window, document));
+      """)
+
+      conn = call_dev_server("/assets/vendor/topbar.js")
+      assert conn.status == 200
+      assert conn.resp_body =~ "export default"
+    end
+
+    test "bundles modules required by a local CommonJS module" do
+      File.write!(Path.join(@fixture_dir, "src/cjs-dep.js"), "module.exports = { answer: 42 }")
+
+      File.write!(
+        Path.join(@fixture_dir, "src/cjs-entry.js"),
+        "exports.answer = require('./cjs-dep').answer"
+      )
+
+      conn = call_dev_server("/assets/cjs-entry.js")
+      assert conn.status == 200
+      assert conn.resp_body =~ "export default"
+      assert conn.resp_body =~ "answer: 42"
+      refute conn.resp_body =~ ~r/require\(['"]\.\/cjs-dep/
+    end
+
+    test "serves .cjs and .cts files as ES modules" do
+      File.write!(Path.join(@fixture_dir, "src/dep.cjs"), "module.exports = { answer: 42 }")
+      File.write!(Path.join(@fixture_dir, "src/typed.cts"), "const n: number = 7; export = { n }")
+
+      for path <- ["/assets/dep.cjs", "/assets/typed.cts"] do
+        conn = call_dev_server(path)
+        assert conn.status == 200
+        assert conn.resp_body =~ "export default"
+      end
+    end
+
+    test "leaves ES modules untouched" do
+      File.write!(Path.join(@fixture_dir, "src/esm.js"), "export const module = { exports: 1 }")
+
+      conn = call_dev_server("/assets/esm.js")
+      assert conn.status == 200
+      refute conn.resp_body =~ "__commonJS"
+    end
+  end
+
+  describe "syntax lowered for a target" do
+    @tag :tmp_dir
+    test "serves the runtime helper a lowered class field imports", %{tmp_dir: project} do
+      # A project of its own, so the helper is not already in the vendor cache.
+      root = Path.join(project, "src")
+      File.mkdir_p!(root)
+      File.mkdir_p!(Path.join(project, "node_modules"))
+
+      File.write!(Path.join(root, "search.ts"), """
+      export class Search {
+        private readonly style = 'field'
+      }
+      """)
+
+      # Class fields are lowered below ES2022, into an import of a helper from
+      # `@oxc-project/runtime`, which is not installed in `node_modules`.
+      opts = [root: root, target: :es2020]
+      conn = call_dev_server("/assets/search.ts", opts)
+      assert conn.status == 200
+
+      assert [helper_url] =
+               Regex.run(~r{/@vendor/[^"]*defineProperty\.js\?v=[a-f0-9]+}, conn.resp_body)
+
+      helper = call_dev_server(helper_url, opts)
+      assert helper.status == 200
+      assert helper.resp_body =~ "function _defineProperty"
+      assert helper.resp_body =~ ~r/export \{[^}]*default/
+    end
+  end
+
   describe "import rewriting" do
     test "rewrites relative imports to absolute paths" do
       File.write!(Path.join(@fixture_dir, "src/utils.ts"), "export const y = 1")
diff --git a/test/volt/dev_server/requests_test.exs b/test/volt/dev_server/requests_test.exs
index 430e04d..64ee347 100644
--- a/test/volt/dev_server/requests_test.exs
+++ b/test/volt/dev_server/requests_test.exs
@@ -1,12 +1,363 @@
 defmodule Volt.DevServer.RequestsTest do
   use Volt.TestSupport.DevServerCase
 
+  @tag :tmp_dir
+  test "Plug attaches to a CLI-owned session and serves current CSS ahead of a stale sink", %{
+    tmp_dir: root
+  } do
+    css = Path.join(root, "app.css")
+    File.write!(css, ".current { color: red }")
+    sink = Path.join(root, "static")
+
+    opts = [
+      root: root,
+      tailwind: true,
+      tailwind_css: css,
+      tailwind_name: "site",
+      tailwind_sources: [],
+      tailwind_sink: sink
+    ]
+
+    session = Volt.Dev.session_identity(opts)
+    on_exit(fn -> Volt.Dev.stop(session) end)
+    assert {:ok, watcher} = Volt.Dev.start(opts)
+
+    config = %{
+      Volt.DevServer.init(root: root, watch: false, session: session)
+      | stylesheet_url: "/assets/site.css",
+        stylesheet_source: css
+    }
+
+    assert config.watcher_opts == nil
+    assert File.regular?(Path.join(sink, "site.css"))
+    File.write!(Path.join(sink, "site.css"), "stale disk output")
+    conn = Plug.Test.conn(:get, "/assets/site.css") |> Volt.DevServer.call(config)
+    assert conn.status == 200
+    assert conn.resp_body =~ ".current"
+    refute conn.resp_body =~ "stale disk"
+    assert {:ok, ^watcher} = Volt.Dev.start(opts)
+  end
+
+  @tag :tmp_dir
+  test "session CSS links to served nested assets without rewriting stored CSS", %{tmp_dir: root} do
+    session = make_ref()
+    File.mkdir_p!(Path.join(root, "css/nested"))
+    source = Path.join(root, "css/app.css")
+    File.write!(source, "@import './nested/theme.css';")
+
+    File.write!(
+      Path.join(root, "css/nested/theme.css"),
+      ".logo { background: url('./logo.svg?v=1#mark') }"
+    )
+
+    File.write!(Path.join(root, "css/nested/logo.svg"), "<svg/>")
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: session,
+         watcher: [
+           root: root,
+           session: session,
+           name: nil,
+           tailwind: true,
+           tailwind_css: source,
+           tailwind_sources: []
+         ]}
+      )
+
+    tables = Volt.Dev.Session.Supervisor.tables(supervisor)
+    {:ok, stored} = Volt.Tailwind.Worker.stylesheet(tables.stylesheet_worker)
+
+    config = %{
+      Volt.DevServer.init(root: root, session: session, session_supervisor: supervisor)
+      | stylesheet_url: "/assets/site.css",
+        stylesheet_source: source
+    }
+
+    response = Plug.Test.conn(:get, "/assets/site.css") |> Volt.DevServer.call(config)
+    assert response.status == 200
+    assert response.resp_body =~ "/assets/css/nested/logo.svg?v=1#mark"
+    asset = Plug.Test.conn(:get, "/assets/css/nested/logo.svg?v=1") |> Volt.DevServer.call(config)
+    assert asset.status == 200
+    assert asset.resp_body == "<svg/>"
+    assert {:ok, ^stored} = Volt.Tailwind.Worker.stylesheet(tables.stylesheet_worker)
+  end
+
+  @tag :tmp_dir
+  test "serves retained CSS without a disk artifact and preserves it on compiler error", %{
+    tmp_dir: root
+  } do
+    session = make_ref()
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: session, watcher: [root: root, session: session, name: nil, tailwind: false]}
+      )
+
+    {_, worker, _, _} =
+      Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+        id == Volt.Tailwind.Worker
+      end)
+
+    assert {:ok, css} =
+             Volt.Tailwind.build(worker: worker, css: ".retained { color: red }", sources: [])
+
+    config = %{
+      Volt.DevServer.init(root: root, session: session, session_supervisor: supervisor)
+      | stylesheet_url: "/assets/site.css"
+    }
+
+    response = Plug.Test.conn(:get, "/assets/site.css") |> Volt.DevServer.call(config)
+    assert response.status == 200
+    assert response.resp_body == css
+    assert Plug.Conn.get_resp_header(response, "content-type") == ["text/css; charset=utf-8"]
+    refute File.exists?(Path.join(root, "site.css"))
+
+    assert {:error, _} =
+             Volt.Tailwind.build(
+               worker: worker,
+               css: "@import './missing.css';",
+               css_base: root,
+               sources: []
+             )
+
+    response = Plug.Test.conn(:get, "/assets/site.css") |> Volt.DevServer.call(config)
+    assert response.resp_body == css
+  end
+
+  defmodule PausedCompiler do
+    @behaviour Volt.Plugin
+    def name, do: "paused-compiler"
+
+    def compile(_path, _source, _opts, parent: parent) do
+      send(parent, {:compiling, self()})
+
+      receive do
+        :continue -> {:ok, %Volt.Pipeline.Result{code: "console.log('compiled')", type: :js}}
+      end
+    end
+  end
+
+  @tag :tmp_dir
+  test "restart during compilation cannot populate the replacement generation", %{tmp_dir: root} do
+    File.write!(Path.join(root, "app.ts"), "console.log('source')")
+    session = make_ref()
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: session, watcher: [root: root, session: session, name: nil, tailwind: false]}
+      )
+
+    config =
+      Volt.DevServer.init(
+        root: root,
+        session: session,
+        session_supervisor: supervisor,
+        plugins: [{PausedCompiler, [parent: self()]}]
+      )
+
+    old = Volt.Dev.Session.Supervisor.tables(supervisor)
+
+    request =
+      Task.async(fn -> Plug.Test.conn(:get, "/assets/app.ts") |> Volt.DevServer.call(config) end)
+
+    assert_receive {:compiling, compiling}
+    monitor = Process.monitor(old.owner)
+    Process.exit(old.owner, :kill)
+    assert_receive {:DOWN, ^monitor, :process, _, :killed}
+    current = Volt.Dev.Session.Supervisor.tables(supervisor)
+    refute current.generation == old.generation
+    send(compiling, :continue)
+    assert Task.await(request).status == 503
+    assert Volt.Cache.get_file(Path.join(root, "app.ts"), current) == nil
+
+    fresh =
+      Task.async(fn -> Plug.Test.conn(:get, "/assets/app.ts") |> Volt.DevServer.call(config) end)
+
+    assert_receive {:compiling, compiling}
+    send(compiling, :continue)
+    assert Task.await(fresh).status == 200
+    assert Volt.Cache.get_file(Path.join(root, "app.ts"), current)
+  end
+
+  @tag :tmp_dir
+  test "stale generation handles return a retryable response", %{tmp_dir: root} do
+    File.write!(Path.join(root, "app.ts"), "console.log('stale')")
+    owner = start_supervised!(Volt.Dev.Session.State)
+    tables = Volt.Dev.Session.State.tables(owner)
+    config = Volt.DevServer.init(root: root, tables: tables, watch: false)
+    stop_supervised!(Volt.Dev.Session.State)
+    conn = Plug.Test.conn(:get, "/assets/app.ts") |> Volt.DevServer.call(config)
+    assert conn.status == 503
+    assert conn.halted
+    assert conn.resp_body =~ "retry"
+  end
+
+  @tag :tmp_dir
+  test "automatic managed sessions serve identical URLs from distinct owned generations", %{
+    tmp_dir: root
+  } do
+    sessions =
+      for label <- ["first", "second"] do
+        directory = Path.join(root, label)
+        File.mkdir_p!(directory)
+        File.write!(Path.join(directory, "app.ts"), "console.log('#{label}')")
+        session = make_ref()
+        on_exit(fn -> Volt.Dev.stop(session) end)
+        {session, directory, Volt.DevServer.init(root: directory, session: session, watch: true)}
+      end
+
+    for {session, directory, config} <- sessions do
+      conn = Plug.Test.conn(:get, "/assets/app.ts") |> Volt.DevServer.call(config)
+      assert conn.status == 200
+      assert conn.resp_body =~ Path.basename(directory)
+      tables = Volt.Dev.tables(session)
+      assert Volt.Cache.get_file(Path.join(directory, "app.ts"), tables)
+      assert Volt.Cache.get_file(Path.join(directory, "app.ts"), session) == nil
+    end
+
+    [{first, _, config}, {second, _, _}] = sessions
+    first_tables = Volt.Dev.tables(first)
+    second_tables = Volt.Dev.tables(second)
+    refute first_tables.owner == second_tables.owner
+    assert :ok = Volt.Dev.stop(first)
+    assert :ets.info(first_tables.cache) == :undefined
+    assert :ets.info(second_tables.cache, :owner) == second_tables.owner
+
+    assert Plug.Test.conn(:get, "/assets/app.ts")
+           |> Volt.DevServer.call(config)
+           |> Map.fetch!(:status) == 200
+
+    refute Volt.Dev.tables(first).generation == first_tables.generation
+  end
+
+  @tag :tmp_dir
+  test "requests share owned tables with their sole watcher", %{tmp_dir: root} do
+    session = make_ref()
+    File.write!(Path.join(root, "app.ts"), "console.log('owned request')")
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: session, watcher: [root: root, session: session, name: nil, tailwind: false]}
+      )
+
+    config = Volt.DevServer.init(root: root, session: session, session_supervisor: supervisor)
+    assert config.watcher_opts == nil
+    conn = Plug.Test.conn(:get, "/assets/app.ts") |> Volt.DevServer.call(config)
+    assert conn.status == 200
+    assert conn.resp_body =~ "owned request"
+    tables = Volt.Dev.Session.Supervisor.tables(supervisor)
+    assert Volt.Cache.get_file(Path.join(root, "app.ts"), tables)
+    assert Volt.Cache.get_file(Path.join(root, "app.ts"), session) == nil
+    assert [_] = Volt.HMR.ModuleGraph.get_by_file(Path.join(root, "app.ts"), tables)
+    assert Volt.HMR.ModuleGraph.get_by_file(Path.join(root, "app.ts"), session) == []
+  end
+
   describe "non-matching paths" do
     test "passes through non-matching prefix" do
       conn = call_dev_server("/other/app.ts")
       refute conn.halted
     end
 
+    test "loads the HMR client in pages the app renders" do
+      page = "<html><head><title>x</title></head><body></body></html>"
+      etag = Volt.HMR.Document.etag(page)
+
+      client =
+        ~s(<script type="module" src="/@volt/client.js" data-volt-etag="#{Plug.HTML.html_escape(etag)}"></script>)
+
+      conn =
+        call_dev_server("/page") |> put_resp_content_type("text/html") |> send_resp(200, page)
+
+      assert conn.resp_body == "<html><head><title>x</title>#{client}</head><body></body></html>"
+      assert get_resp_header(conn, "etag") == [etag]
+
+      loaded =
+        ~s(<html><head><script type="module" src="/@volt/client.js"></script></head></html>)
+
+      # A page that already loads the client gets the entity tag on its own tag.
+      loaded_etag = Volt.HMR.Document.etag(loaded)
+
+      conn =
+        call_dev_server("/page") |> put_resp_content_type("text/html") |> send_resp(200, loaded)
+
+      assert conn.resp_body ==
+               String.replace(
+                 loaded,
+                 ~s(client.js"),
+                 ~s(client.js" data-volt-etag="#{Plug.HTML.html_escape(loaded_etag)}")
+               )
+
+      assert get_resp_header(conn, "etag") == [loaded_etag]
+
+      conn =
+        call_dev_server("/page")
+        |> put_req_header("if-none-match", loaded_etag)
+        |> put_resp_content_type("text/html")
+        |> send_resp(200, loaded)
+
+      assert conn.status == 304
+
+      conn =
+        call_dev_server("/api")
+        |> put_resp_content_type("application/json")
+        |> send_resp(200, "{}")
+
+      assert conn.resp_body == "{}"
+    end
+
+    test "answers 304 when a page revalidates HTML that has not changed" do
+      page = "<html><head></head><body>same</body></html>"
+      etag = Volt.HMR.Document.etag(page)
+
+      send_page = fn html, etag ->
+        call_dev_server("/page")
+        |> put_req_header("if-none-match", etag)
+        |> put_resp_content_type("text/html")
+        |> send_resp(200, html)
+      end
+
+      conn = send_page.(page, etag)
+      assert conn.status == 304
+      assert conn.resp_body == ""
+
+      conn = send_page.("<html><head></head><body>changed</body></html>", etag)
+      assert conn.status == 200
+      assert conn.resp_body =~ "changed"
+      assert get_resp_header(conn, "etag") != [etag]
+    end
+
+    test "marks pages for in-place updates when the server opts in" do
+      page = "<html><head></head><body></body></html>"
+
+      send_page = fn opts ->
+        call_dev_server("/page", opts)
+        |> put_resp_content_type("text/html")
+        |> send_resp(200, page)
+      end
+
+      refute send_page.([]).resp_body =~ "data-volt-morph"
+      assert send_page.(morph: true).resp_body =~ ~s( data-volt-morph="")
+
+      assert send_page.(morph: [preserve: "[data-island]"]).resp_body =~
+               ~s( data-volt-morph="[data-island]")
+    end
+
+    test "error pages get the HMR client without an entity tag" do
+      conn =
+        call_dev_server("/page")
+        |> put_resp_content_type("text/html")
+        |> send_resp(500, "<html><head></head><body>boom</body></html>")
+
+      assert conn.status == 500
+      assert conn.resp_body =~ ~s(<script type="module" src="/@volt/client.js"></script>)
+      assert get_resp_header(conn, "etag") == []
+    end
+
     test "serves static assets with correct MIME type" do
       File.write!(Path.join(@fixture_dir, "src/image.png"), "binary")
       conn = call_dev_server("/assets/image.png")
@@ -75,12 +426,21 @@ defmodule Volt.DevServer.RequestsTest do
   end
 
   describe "error handling" do
-    test "returns 500 with error overlay for invalid source" do
-      File.write!(Path.join(@fixture_dir, "src/bad.ts"), "const = ;")
+    test "reports compile errors to the HMR client until the module compiles" do
+      path = Path.join(@fixture_dir, "src/bad.ts")
+      File.write!(path, "const = ;")
+
       conn = call_dev_server("/assets/bad.ts")
       assert conn.status == 500
-      assert conn.resp_body =~ "renderErrorOverlay"
-      assert conn.resp_body =~ "Compilation error"
+      assert conn.resp_body =~ "Could not compile"
+
+      assert [%{line: 1, column: 7, frame: frame, file: file}] = Volt.HMR.Errors.list(:default)
+      assert file == Path.relative_to_cwd(path)
+      assert frame =~ "> 1 | const = ;"
+
+      File.write!(path, "export const ok = 1")
+      assert call_dev_server("/assets/bad.ts").status == 200
+      assert Volt.HMR.Errors.list(:default) == []
     end
   end
 end
diff --git a/test/volt/dev_test.exs b/test/volt/dev_test.exs
index 0b44782..8966c5d 100644
--- a/test/volt/dev_test.exs
+++ b/test/volt/dev_test.exs
@@ -1,36 +1,168 @@
 defmodule Volt.DevTest do
   use ExUnit.Case, async: false
 
-  test "starts one supervised watcher per profile and asset root" do
-    root = Path.join(System.tmp_dir!(), "volt-dev-#{System.unique_integer([:positive])}")
-    File.mkdir_p!(root)
+  @tag :tmp_dir
+  test "cached asset requests do not wait for the watcher to finish rebuilding", %{tmp_dir: root} do
+    File.write!(Path.join(root, "app.js"), "export default 1")
+    config = Volt.DevServer.init(root: root, watch: true)
+    request = fn -> Plug.Test.conn(:get, "/assets/app.js") |> Volt.DevServer.call(config) end
+    assert request.().status == 200
+    assert {:ok, watcher} = Volt.Dev.start(config.watcher_opts)
+    :sys.suspend(watcher)
+
+    try do
+      task = Task.async(request)
+      assert Task.await(task, 1_000).status == 200
+    after
+      :sys.resume(watcher)
+      Volt.Dev.stop(config.session)
+    end
+  end
+
+  @tag :tmp_dir
+  test "explicit compatibility sink is written by the session-owned worker", %{tmp_dir: root} do
+    source = Path.join(root, "app.css")
+    File.write!(source, ".sink { color: red }")
+    sink = Path.join(root, "static")
+    session = make_ref()
+
+    assert {:ok, watcher} =
+             Volt.Dev.start(
+               session: session,
+               root: root,
+               tailwind: true,
+               tailwind_css: source,
+               tailwind_name: "site",
+               tailwind_sources: [],
+               tailwind_sink: sink
+             )
+
+    on_exit(fn -> Volt.Dev.stop(session) end)
+    tables = :sys.get_state(watcher).tables
+    assert {:ok, css} = Volt.Tailwind.Worker.stylesheet(tables.stylesheet_worker)
+    assert File.read!(Path.join(sink, "site.css")) == css
+    assert :sys.get_state(watcher).tailwind_outdir == sink
+  end
 
-    assert :ok = Volt.Dev.ensure_watcher(id: :default, root: root, tailwind: false)
-    assert [{pid, _}] = Registry.lookup(Volt.Dev.WatcherRegistry, {:watcher, :default, root})
+  @tag :tmp_dir
+  test "Tailwind contexts are isolated and released with explicit sessions", %{tmp_dir: root} do
+    a = make_ref()
+    b = make_ref()
+    css = Path.join(root, "input.css")
+    File.write!(css, "@tailwind utilities;")
+    options = [root: root, tailwind: true, tailwind_css: css, tailwind_sources: []]
 
     on_exit(fn ->
-      if Process.alive?(pid) do
-        DynamicSupervisor.terminate_child(Volt.Dev.WatcherSupervisor, pid)
-      end
+      Volt.Dev.stop(a)
+      Volt.Dev.stop(b)
+    end)
 
-      File.rm_rf!(root)
+    assert {:ok, first} =
+             Volt.Dev.start([session: a, tailwind_outdir: Path.join(root, "a")] ++ options)
+
+    assert {:ok, second} =
+             Volt.Dev.start([session: b, tailwind_outdir: Path.join(root, "b")] ++ options)
+
+    first_worker = GenServer.whereis(:sys.get_state(first).config.tailwind_worker)
+    second_worker = GenServer.whereis(:sys.get_state(second).config.tailwind_worker)
+    refute first_worker == second_worker
+    assert :ok = Volt.Dev.stop(a)
+    refute Process.alive?(first_worker)
+    assert Process.alive?(second_worker)
+    assert :ok = Volt.Dev.stop(b)
+    refute Process.alive?(second_worker)
+  end
+
+  @tag :tmp_dir
+  test "owner exit stops its watcher and clears its state", %{tmp_dir: root} do
+    session = make_ref()
+
+    owner =
+      spawn(fn ->
+        receive do
+          :finish -> :ok
+        end
+      end)
+
+    assert {:ok, watcher} =
+             Volt.Dev.start(session: session, root: root, owner: owner, tailwind: false)
+
+    on_exit(fn ->
+      Process.exit(owner, :kill)
+      Volt.Dev.stop(session)
     end)
 
-    assert Process.alive?(pid)
-    assert :ok = Volt.Dev.ensure_watcher(id: :default, root: root, tailwind: false)
-    assert [{^pid, _}] = Registry.lookup(Volt.Dev.WatcherRegistry, {:watcher, :default, root})
+    Volt.Cache.put("/app.js", 1, %Volt.DevServer.CacheEntry{code: "owned"}, session)
+    monitor = Process.monitor(watcher)
+    send(owner, :finish)
+    assert_receive {:DOWN, ^monitor, :process, ^watcher, :normal}
+    assert Volt.Cache.get_file("/app.js", session) == nil
+    # Supervisor calls are a barrier after processing the linked child's exit.
+    children = DynamicSupervisor.which_children(Volt.Dev.WatcherSupervisor)
+    refute Enum.any?(children, fn {_, pid, _, _} -> pid == watcher end)
+  end
+
+  @tag :tmp_dir
+  test "concurrent starts share one watcher and normalized directory options", %{tmp_dir: root} do
+    session = make_ref()
+    opts = [session: session, root: root, tailwind: false]
+    on_exit(fn -> Volt.Dev.stop(session) end)
+
+    results =
+      1..8
+      |> Task.async_stream(fn _ -> Volt.Dev.start(opts) end, timeout: 15_000)
+      |> Enum.to_list()
+
+    pids = Enum.map(results, fn {:ok, {:ok, pid}} -> pid end)
+    assert [pid] = Enum.uniq(pids)
+    assert {:ok, ^pid} = Volt.Dev.start(opts ++ [watch_dirs: [], reload_dirs: []])
+    assert :ok = Volt.Dev.stop(session)
+    refute Process.alive?(pid)
+    assert {:ok, replacement} = Volt.Dev.start(opts)
+    refute replacement == pid
+    assert Process.alive?(replacement)
+  end
 
-    assert :ok = Volt.Dev.ensure_watcher(id: :admin, root: root, tailwind: false)
+  @tag :tmp_dir
+  test "explicit sessions reject conflicting roots and stop clears state", %{tmp_dir: root} do
+    session = make_ref()
+    opts = [session: session, root: root, tailwind: false]
+    assert {:ok, pid} = Volt.Dev.start(opts)
+    on_exit(fn -> Volt.Dev.stop(session) end)
+    assert {:ok, ^pid} = Volt.Dev.start(opts)
 
-    assert [{profile_pid, _}] =
-             Registry.lookup(Volt.Dev.WatcherRegistry, {:watcher, :admin, root})
+    assert {:error, :session_configuration_conflict} =
+             Volt.Dev.start(Keyword.put(opts, :root, Path.join(root, "other")))
+
+    Volt.Cache.put("/app.js", 1, %Volt.DevServer.CacheEntry{code: "session"}, session)
+    Volt.HMR.ImportGraph.update("/app.js", ["./child.js"], session)
+    Volt.HMR.ModuleGraph.update_module("/app.js", "/app.js", "/app.js", [], session: session)
+    assert :ok = Volt.Dev.stop(session)
+    refute Process.alive?(pid)
+    assert Volt.Cache.get_file("/app.js", session) == nil
+    assert Volt.HMR.ImportGraph.imports_of("/app.js", session) == []
+    assert Volt.HMR.ModuleGraph.get_by_url("/app.js", session) == nil
+    assert :ok = Volt.Dev.stop(session)
+  end
+
+  test "starts one supervised watcher per profile and asset root" do
+    root = Path.expand("volt-dev-#{System.unique_integer([:positive])}", System.tmp_dir!())
+    File.mkdir_p!(root)
+
+    default = Volt.Dev.session_identity(root: root)
+    admin = Volt.Dev.session_identity(root: root, id: :admin)
 
     on_exit(fn ->
-      if Process.alive?(profile_pid) do
-        DynamicSupervisor.terminate_child(Volt.Dev.WatcherSupervisor, profile_pid)
-      end
+      Volt.Dev.stop(default)
+      Volt.Dev.stop(admin)
+      File.rm_rf!(root)
     end)
 
+    assert {:ok, pid} = Volt.Dev.start(root: root, tailwind: false)
+    assert {:ok, ^pid} = Volt.Dev.start(id: :default, root: root, tailwind: false)
+    assert {:ok, profile_pid} = Volt.Dev.start(id: :admin, root: root, tailwind: false)
+    assert :sys.get_state(pid).tables == Volt.Dev.tables(default)
+    refute Volt.Dev.tables(default).owner == Volt.Dev.tables(admin).owner
     assert profile_pid != pid
   end
 end
diff --git a/test/volt/hmr/boundary_test.exs b/test/volt/hmr/boundary_test.exs
index 1cf5e65..5ab694d 100644
--- a/test/volt/hmr/boundary_test.exs
+++ b/test/volt/hmr/boundary_test.exs
@@ -3,6 +3,38 @@ defmodule Volt.HMR.BoundaryTest do
 
   alias Volt.HMR.Boundary
 
+  test "boundary lookup isolates both served and fallback import graphs" do
+    alias Volt.HMR.{ImportGraph, ModuleGraph}
+    a = make_ref()
+    b = make_ref()
+
+    on_exit(fn ->
+      for session <- [a, b] do
+        ImportGraph.clear_session(session)
+        ModuleGraph.clear_session(session)
+      end
+    end)
+
+    child = "/session/child.js"
+    parent = "/session/parent.js"
+
+    read = fn path ->
+      if path == parent, do: "import.meta.hot.accept()", else: "export default 1"
+    end
+
+    ImportGraph.update(parent, ["./child.js"], a)
+    assert Boundary.find_boundary(child, read, a) == {:ok, parent}
+    assert Boundary.find_boundary(child, read, b) == :full_reload
+    ModuleGraph.update_module("/child.js", child, child, [], session: a)
+    ModuleGraph.update_module("/parent.js", parent, parent, [child], session: a)
+    ModuleGraph.update_module("/child.js", child, child, [], session: b)
+    assert Boundary.find_boundary(child, read, a) == {:ok, parent}
+    assert Boundary.find_boundary(child, read, b) == :full_reload
+    ModuleGraph.invalidate_file(child, 123, a)
+    assert ModuleGraph.get_by_id(child, a).last_invalidated_at == 123
+    assert ModuleGraph.get_by_id(child, b).last_invalidated_at == nil
+  end
+
   describe "self_accepting?/1" do
     test "detects import.meta.hot.accept()" do
       assert Boundary.self_accepting?("""
@@ -63,30 +95,30 @@ defmodule Volt.HMR.BoundaryTest do
     end
 
     test "finds dependency-accepting boundary in parent module through HMR module graph" do
+      app = Path.expand("app/App.tsx")
+      button = Path.expand("app/Button.tsx")
+
       Volt.HMR.ModuleGraph.update_module(
         "/assets/App.tsx",
         "/assets/App.tsx",
-        "/app/App.tsx",
+        app,
         ["/assets/Button.tsx"]
       )
 
       Volt.HMR.ModuleGraph.update_module(
         "/assets/Button.tsx",
         "/assets/Button.tsx",
-        "/app/Button.tsx",
+        button,
         []
       )
 
-      read = fn
-        "/app/App.tsx" ->
-          "import Button from './Button'\nif (import.meta.hot) { import.meta.hot.accept('./Button', () => {}) }"
+      sources = %{
+        app =>
+          "import Button from './Button'\nif (import.meta.hot) { import.meta.hot.accept('./Button', () => {}) }",
+        button => "export default function Button() {}"
+      }
 
-        "/app/Button.tsx" ->
-          "export default function Button() {}"
-      end
-
-      assert {:ok, "/app/App.tsx"} =
-               Boundary.find_boundary("/app/Button.tsx", read)
+      assert {:ok, ^app} = Boundary.find_boundary(button, &Map.fetch!(sources, &1))
     end
 
     test "finds boundary in parent module through HMR module graph" do
diff --git a/test/volt/hmr/document_test.exs b/test/volt/hmr/document_test.exs
new file mode 100644
index 0000000..5612a4a
--- /dev/null
+++ b/test/volt/hmr/document_test.exs
@@ -0,0 +1,100 @@
+defmodule Volt.HMR.DocumentTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.HMR.Document
+
+  defp page(body, head \\ "") do
+    "<html><head><title>t</title>#{head}</head><body>#{body}</body></html>"
+  end
+
+  describe "changes/3" do
+    test "patches changes to content" do
+      assert Document.changes(page("<p>one</p>"), page("<p class=\"x\">two</p>"), nil) ==
+               {:patch, %{owned: [], root: %{}, head: %{remove: [], add: []}}}
+    end
+
+    test "patches data blocks, which the browser does not run" do
+      before = page(~s(<script type="application/json">{"a":1}</script>))
+      now = page(~s(<script type="application/json">{"a":2}</script>))
+
+      assert Document.changes(before, now, nil) ==
+               {:patch, %{owned: [], root: %{}, head: %{remove: [], add: []}}}
+    end
+
+    test "reloads when the scripts the page runs differ" do
+      before = page(~s(<script type="module" src="/app.ts"></script>))
+
+      assert Document.changes(before, page(~s(<script type="module" src="/b.ts"></script>)), nil) ==
+               :reload
+
+      assert Document.changes(page("<script>a()</script>"), page("<script>b()</script>"), nil) ==
+               :reload
+
+      assert Document.changes(before, page(""), nil) == :reload
+    end
+
+    test "reloads when the stylesheets differ" do
+      link = ~s(<link rel="stylesheet" href="/a.css">)
+
+      assert Document.changes(
+               page("", link),
+               page("", ~s(<link rel="stylesheet" href="/b.css">)),
+               nil
+             ) ==
+               :reload
+
+      assert Document.changes(page("", "<style>a{}</style>"), page("", "<style>b{}</style>"), nil) ==
+               :reload
+    end
+
+    test "names the owned elements whose attributes the server changed" do
+      before =
+        page(
+          ~s(<div data-island="a" data-props="1"></div><div data-island="b" data-props="1"></div>)
+        )
+
+      now =
+        page(
+          ~s(<div data-island="a" data-props="1"></div><div data-island="b" data-props="2"></div>)
+        )
+
+      assert {:patch, %{owned: owned}} = Document.changes(before, now, "[data-island]")
+      assert owned == [%{index: 1, attributes: %{"data-island" => "b", "data-props" => "2"}}]
+    end
+
+    test "names the attributes the server changed on html and body" do
+      before =
+        ~s(<html lang="en" data-a="1"><head></head><body class="old"><p>x</p></body></html>)
+
+      now =
+        ~s(<html lang="ru"><head></head><body class="old" data-route="/x"><p>x</p></body></html>)
+
+      assert {:patch, %{root: root}} = Document.changes(before, now, nil)
+
+      assert root == %{
+               "html" => %{set: %{"lang" => "ru"}, remove: ["data-a"]},
+               "body" => %{set: %{"data-route" => "/x"}, remove: []}
+             }
+    end
+
+    test "names the head elements that are gone and that are new" do
+      before =
+        page("", ~s(<meta name="description" content="old"><link rel="icon" href="/i.png">))
+
+      now = page("", ~s(<meta name="description" content="new"><link rel="icon" href="/i.png">))
+
+      assert {:patch, %{head: head}} = Document.changes(before, now, nil)
+
+      assert head == %{
+               remove: [~s(<meta name="description" content="old"/>)],
+               add: [~s(<meta name="description" content="new"/>)]
+             }
+    end
+
+    test "reloads when owned elements are added or removed" do
+      before = page(~s(<div data-island="a"></div>))
+
+      assert Document.changes(before, page(""), "[data-island]") == :reload
+    end
+  end
+end
diff --git a/test/volt/hmr/glob_graph_test.exs b/test/volt/hmr/glob_graph_test.exs
index 912f89b..5ce9172 100644
--- a/test/volt/hmr/glob_graph_test.exs
+++ b/test/volt/hmr/glob_graph_test.exs
@@ -8,6 +8,19 @@ defmodule Volt.HMR.GlobGraphTest do
     :ok
   end
 
+  test "isolates glob ownership, removal, and cleanup by session" do
+    importer = "/src/routes.ts"
+    GlobGraph.update(importer, ["/src/a/*.ts"], :a)
+    GlobGraph.update(importer, ["/src/b/*.ts"], :b)
+    assert GlobGraph.dependents("/src/a/page.ts", :a) == [importer]
+    assert GlobGraph.dependents("/src/a/page.ts", :b) == []
+    assert GlobGraph.dependents("/src/a/page.ts") == []
+    GlobGraph.remove(importer, :a)
+    assert GlobGraph.dependents("/src/b/page.ts", :b) == [importer]
+    GlobGraph.clear_session(:b)
+    assert GlobGraph.dependents("/src/b/page.ts", :b) == []
+  end
+
   test "finds importers whose glob patterns match a path" do
     GlobGraph.update("/src/routes.ts", ["/src/pages/*.ts"])
 
@@ -15,6 +28,12 @@ defmodule Volt.HMR.GlobGraphTest do
     assert GlobGraph.dependents("/src/components/home.ts") == []
   end
 
+  test "matches Windows drive letters case-insensitively" do
+    GlobGraph.update("C:/src/routes.ts", ["c:/src/pages/*.ts"])
+
+    assert GlobGraph.dependents("C:/src/pages/home.ts") == ["C:/src/routes.ts"]
+  end
+
   test "honors negated patterns" do
     GlobGraph.update("/src/routes.ts", ["/src/pages/*.ts", "!/src/pages/*.test.ts"])
 
@@ -24,9 +43,11 @@ defmodule Volt.HMR.GlobGraphTest do
 
   test "extracts patterns from import.meta.glob source" do
     source = "const pages = import.meta.glob('./pages/*.ts')"
+    importer = Path.expand("src/routes.ts")
+    page = Path.expand("src/pages/home.ts")
 
-    GlobGraph.update_from_source("/src/routes.ts", source)
+    GlobGraph.update_from_source(importer, source)
 
-    assert GlobGraph.dependents("/src/pages/home.ts") == ["/src/routes.ts"]
+    assert GlobGraph.dependents(page) == [importer]
   end
 end
diff --git a/test/volt/hmr/socket_test.exs b/test/volt/hmr/socket_test.exs
index 15d0a48..cffa620 100644
--- a/test/volt/hmr/socket_test.exs
+++ b/test/volt/hmr/socket_test.exs
@@ -1,12 +1,150 @@
 defmodule Volt.HMR.SocketTest do
   use ExUnit.Case, async: false
 
+  setup do
+    Volt.HMR.Errors.clear_session(:default)
+    on_exit(fn -> Volt.HMR.Errors.clear_session(:default) end)
+  end
+
   describe "init/1" do
     test "registers with registry" do
       {:ok, _state} = Volt.HMR.Socket.init(nil)
       me = self()
       assert {me, nil} in Registry.lookup(Volt.HMR.Registry, :clients)
     end
+
+    test "sends current errors to a new client" do
+      Volt.HMR.error("app.ts", "boom")
+
+      {:push, {:text, json}, _state} = Volt.HMR.Socket.init(nil)
+
+      assert %{"type" => "error", "payload" => %{"errors" => [%{"message" => "boom"}]}} =
+               Jason.decode!(json)
+    end
+  end
+
+  describe "a page the server keeps a render of" do
+    setup do
+      {:ok, renders} = Agent.start_link(fn -> page("first", ~s({"n":1})) end)
+      document = fn "/post" -> {:ok, Agent.get(renders, & &1)} end
+
+      {:ok, state} =
+        Volt.HMR.Socket.init(document: document, morph: [preserve: "[data-island]"])
+
+      html = Agent.get(renders, & &1)
+      opened = open_page(state, "/post", Volt.HMR.Document.etag(html))
+      %{renders: renders, state: state, opened: opened}
+    end
+
+    test "hears nothing when its HTML did not change", %{opened: opened} do
+      assert {:ok, ^opened} = Volt.HMR.Socket.handle_info(document_update(), opened)
+    end
+
+    test "is sent the new HTML when it can be patched", %{renders: renders, opened: opened} do
+      Agent.update(renders, fn _ -> page("second", ~s({"n":1})) end)
+
+      assert {:push, {:text, json}, state} =
+               Volt.HMR.Socket.handle_info(document_update(), opened)
+
+      assert %{"changes" => ["document"], "html" => html, "etag" => etag, "owned" => []} =
+               Jason.decode!(json)["payload"]
+
+      assert html =~ "second"
+
+      # The pushed page keeps what marks it for the next update.
+      assert html =~ ~s(data-volt-morph="[data-island]")
+      assert html =~ "data-volt-etag"
+      assert etag == Volt.HMR.Document.etag(Agent.get(renders, & &1))
+
+      # The new render is what the next change is compared with.
+      assert {:ok, ^state} = Volt.HMR.Socket.handle_info(document_update(), state)
+    end
+
+    test "is told which owned elements the server changed", %{renders: renders, opened: opened} do
+      Agent.update(renders, fn _ -> page("first", ~s({"n":2})) end)
+
+      assert {:push, {:text, json}, _state} =
+               Volt.HMR.Socket.handle_info(document_update(), opened)
+
+      assert [%{"index" => 0, "attributes" => %{"data-props" => ~s({"n":2})}}] =
+               Jason.decode!(json)["payload"]["owned"]
+    end
+
+    test "reloads when the change cannot be patched", %{renders: renders, opened: opened} do
+      Agent.update(renders, fn html -> String.replace(html, "run()", "run(2)") end)
+
+      assert {:push, {:text, json}, _state} =
+               Volt.HMR.Socket.handle_info(document_update(), opened)
+
+      payload = Jason.decode!(json)["payload"]
+      assert payload["changes"] == ["full"]
+      refute Map.has_key?(payload, "html")
+    end
+
+    test "revalidates itself when it was served different HTML", %{state: state} do
+      stale = open_page(state, "/post", ~s("another"))
+
+      assert {:push, {:text, json}, _state} =
+               Volt.HMR.Socket.handle_info(document_update(), stale)
+
+      payload = Jason.decode!(json)["payload"]
+      assert payload["changes"] == ["document"]
+      refute Map.has_key?(payload, "html")
+    end
+
+    test "starts from the HTML it was served without rendering again" do
+      {:ok, calls} = Agent.start_link(fn -> 0 end)
+
+      document = fn "/post" ->
+        Agent.update(calls, &(&1 + 1))
+        {:ok, page("first", "{}")}
+      end
+
+      served = page("first", "{}")
+      etag = Volt.HMR.Document.etag(served)
+      Volt.HMR.Documents.put(:default, etag, served)
+      on_exit(fn -> Volt.HMR.Documents.clear_session(:default) end)
+
+      {:ok, state} = Volt.HMR.Socket.init(document: document, morph: true)
+      opened = open_page(state, "/post", etag)
+
+      assert opened.html == served
+      assert Agent.get(calls, & &1) == 0
+    end
+
+    test "is not kept track of unless pages are patched in place", %{renders: renders} do
+      document = fn "/post" -> {:ok, Agent.get(renders, & &1)} end
+      {:ok, state} = Volt.HMR.Socket.init(document: document)
+      html = Agent.get(renders, & &1)
+      opened = open_page(state, "/post", Volt.HMR.Document.etag(html))
+
+      Agent.update(renders, fn _ -> page("second", "{}") end)
+
+      assert {:push, {:text, json}, _state} =
+               Volt.HMR.Socket.handle_info(document_update(), opened)
+
+      refute Map.has_key?(Jason.decode!(json)["payload"], "html")
+    end
+
+    defp page(text, props) do
+      """
+      <html><head><title>Post</title></head><body>
+        <p>#{text}</p>
+        <div data-island="counter" data-props='#{props}'></div>
+        <script>run()</script>
+        <script type="module" src="/@volt/client.js"></script>
+      </body></html>
+      """
+    end
+
+    defp open_page(state, path, etag) do
+      frame = Jason.encode!(%{type: "page", payload: %{path: path, etag: etag}})
+      {:ok, state} = Volt.HMR.Socket.handle_in({frame, opcode: :text}, state)
+      state
+    end
+
+    defp document_update,
+      do: {:volt_hmr, :update, %{path: "content/post.md", changes: ["document"]}}
   end
 
   describe "handle_info/2" do
diff --git a/test/volt/hmr/style_dependencies_test.exs b/test/volt/hmr/style_dependencies_test.exs
index e38da27..a2afb94 100644
--- a/test/volt/hmr/style_dependencies_test.exs
+++ b/test/volt/hmr/style_dependencies_test.exs
@@ -1,7 +1,7 @@
 defmodule Volt.HMR.StyleDependenciesTest do
   use ExUnit.Case, async: false
 
-  @root Path.join(System.tmp_dir!(), "volt-style-dependencies-test")
+  @root Path.expand("volt-style-dependencies-test", System.tmp_dir!())
 
   setup do
     Volt.HMR.StyleGraph.clear()
diff --git a/test/volt/hmr/style_graph_test.exs b/test/volt/hmr/style_graph_test.exs
index 6fbf1f2..4f0ae15 100644
--- a/test/volt/hmr/style_graph_test.exs
+++ b/test/volt/hmr/style_graph_test.exs
@@ -6,6 +6,19 @@ defmodule Volt.HMR.StyleGraphTest do
     :ok
   end
 
+  test "transitive edges and cleanup remain inside their session" do
+    alias Volt.HMR.StyleGraph
+    StyleGraph.update("/app.css", ["/theme.css"], :a)
+    StyleGraph.update("/theme.css", ["/tokens.css"], :a)
+    StyleGraph.update("/app.css", ["/other.css"], :b)
+    assert Enum.sort(StyleGraph.dependents("/tokens.css", :a)) == ["/app.css", "/theme.css"]
+    assert StyleGraph.dependents("/tokens.css", :b) == []
+    assert StyleGraph.dependents("/tokens.css") == []
+    StyleGraph.clear_session(:a)
+    assert StyleGraph.dependencies_of("/app.css", :a) == []
+    assert StyleGraph.dependents("/other.css", :b) == ["/app.css"]
+  end
+
   test "tracks direct dependencies and transitive dependents" do
     app = "/app/app.css"
     theme = "/app/theme.css"
diff --git a/test/volt/hmr_test.exs b/test/volt/hmr_test.exs
index 8960d5a..fd01811 100644
--- a/test/volt/hmr_test.exs
+++ b/test/volt/hmr_test.exs
@@ -3,7 +3,44 @@ defmodule Volt.HMRTest do
 
   setup do
     Registry.register(Volt.HMR.Registry, :clients, nil)
-    :ok
+    Volt.HMR.Errors.clear_session(:default)
+    on_exit(fn -> Volt.HMR.Errors.clear_session(:default) end)
+  end
+
+  test "scoped broadcasts do not reach other sessions or default subscribers" do
+    parent = self()
+
+    clients =
+      for session <- [:site_a, :site_b] do
+        pid =
+          spawn_link(fn ->
+            {:ok, _} = Volt.HMR.Socket.init(session: session)
+            send(parent, {:ready, self()})
+
+            receive do
+              :inspect -> send(parent, {:messages, self(), Process.info(self(), :messages)})
+            end
+          end)
+
+        assert_receive {:ready, ^pid}
+        {session, pid}
+      end
+
+    Volt.HMR.style_update("/assets/app.css", session: :site_a)
+    for {_session, pid} <- clients, do: send(pid, :inspect)
+
+    for {session, pid} <- clients do
+      assert_receive {:messages, ^pid, {:messages, messages}}
+
+      expected =
+        if session == :site_a,
+          do: [{:volt_hmr, :update, %{path: "/assets/app.css", changes: ["style"]}}],
+          else: []
+
+      assert messages == expected
+    end
+
+    refute_received {:volt_hmr, _, _}
   end
 
   test "broadcast sends HMR messages to connected clients" do
@@ -32,9 +69,20 @@ defmodule Volt.HMRTest do
     assert_receive {:volt_hmr, :update, %{path: "app.css", changes: ["style"]}}
   end
 
-  test "error broadcasts error payload" do
-    assert :ok = Volt.HMR.error("index.html", "boom")
-    assert_receive {:volt_hmr, :error, %{path: "index.html", reason: "boom"}}
+  test "error broadcasts the current errors until they are cleared" do
+    assert :ok = Volt.HMR.error("index.html", "boom", title: "Render error")
+
+    assert_receive {:volt_hmr, :error,
+                    %{errors: [%{message: "boom", file: "index.html", title: "Render error"}]}}
+
+    assert :ok = Volt.HMR.error("app.ts", "bang")
+    assert_receive {:volt_hmr, :error, %{errors: [%{message: "bang"}, %{message: "boom"}]}}
+
+    assert :ok = Volt.HMR.clear_error("index.html")
+    assert_receive {:volt_hmr, :error, %{errors: [%{message: "bang"}]}}
+
+    assert :ok = Volt.HMR.clear_error("index.html")
+    refute_receive {:volt_hmr, :error, _payload}
   end
 
   test "invalidate_file evicts dev compilation state" do
diff --git a/test/volt/integration/hmr_test.exs b/test/volt/integration/hmr_test.exs
index 53a0e10..41fbb4a 100644
--- a/test/volt/integration/hmr_test.exs
+++ b/test/volt/integration/hmr_test.exs
@@ -8,7 +8,82 @@ defmodule Volt.Integration.TestPlug do
   def init(opts), do: opts
 
   @impl true
-  def call(conn, opts) do
+  # Pages rendered from content files, sent through the dev server as an app's
+  # own pages are.
+  def call(%Conn{request_path: "/doc/" <> name} = conn, opts),
+    do: document(conn, name, opts[:root], opts[:dev_server])
+
+  def call(%Conn{request_path: "/morph/" <> name} = conn, opts),
+    do: document(conn, name, opts[:root], opts[:morph_dev_server])
+
+  # A page the server can render outside a request, so the page's websocket
+  # process compares renders and pushes what changed.
+  def call(%Conn{request_path: "/push/" <> _name = path} = conn, opts) do
+    {:ok, html} = render(path, opts[:root])
+
+    conn
+    |> Volt.DevServer.call(opts[:push_dev_server])
+    |> Conn.put_resp_content_type("text/html")
+    |> Conn.send_resp(200, html)
+  end
+
+  # Every page shares one websocket endpoint, served by the dev server that can
+  # render documents; it only knows the `/push/` pages.
+  def call(%Conn{request_path: "/@volt/ws"} = conn, opts),
+    do: Volt.DevServer.call(conn, opts[:push_dev_server])
+
+  def call(conn, opts), do: asset(conn, opts)
+
+  def render("/push/" <> name, root) do
+    [text, props, lang, description] =
+      Path.join(root <> "-content", name <> ".md") |> File.read!() |> String.split("|")
+
+    {:ok,
+     """
+     <!DOCTYPE html>
+     <html lang="#{lang}"><head><title>#{name}</title>
+     <meta name="description" content="#{description}">
+     </head><body>
+       <div id="content">#{text}</div>
+       <div id="owned" data-owned data-props="#{props}"></div>
+       <script>
+         const loads = Number(sessionStorage.getItem('voltPushLoads') ?? '0') + 1
+         sessionStorage.setItem('voltPushLoads', String(loads))
+         document.body.dataset.loads = String(loads)
+         document.documentElement.dataset.theme = 'dark'
+         const owned = document.getElementById('owned')
+         owned.textContent = 'props:' + owned.dataset.props
+         owned.addEventListener('volt:element-update', (event) => {
+           event.preventDefault()
+           owned.textContent = 'props:' + owned.dataset.props
+         })
+       </script>
+     </body></html>
+     """}
+  end
+
+  def render(_path, _root), do: :error
+
+  defp document(conn, name, root, dev_server) do
+    content = File.read!(Path.join(root <> "-content", name <> ".md"))
+
+    conn
+    |> Volt.DevServer.call(dev_server)
+    |> Conn.put_resp_content_type("text/html")
+    |> Conn.send_resp(200, """
+    <!DOCTYPE html>
+    <html><head><title>#{name}</title></head><body>
+      <div id="content">#{content}</div>
+      <script>
+        const loads = Number(sessionStorage.getItem('voltDocLoads') ?? '0') + 1
+        sessionStorage.setItem('voltDocLoads', String(loads))
+        document.body.dataset.loads = String(loads)
+      </script>
+    </body></html>
+    """)
+  end
+
+  defp asset(conn, opts) do
     if String.ends_with?(conn.request_path, ".html") or conn.request_path == "/" do
       file =
         case conn.request_path do
@@ -87,7 +162,7 @@ defmodule Volt.Integration.HMRTest do
   end
 
   defp playwright_executable do
-    local = Path.expand("node_modules/.bin/playwright")
+    local = Path.expand("node_modules/playwright/cli.js")
     if File.exists?(local), do: local, else: "playwright"
   end
 
@@ -117,7 +192,22 @@ defmodule Volt.Integration.HMRTest do
     """)
 
     dev_server_opts = Volt.DevServer.init(root: @fixture_dir, prefix: "/assets")
-    plug_opts = %{root: @fixture_dir, dev_server: dev_server_opts}
+    morph_opts = Volt.DevServer.init(root: @fixture_dir, prefix: "/assets", morph: true)
+
+    push_opts =
+      Volt.DevServer.init(
+        root: @fixture_dir,
+        prefix: "/assets",
+        morph: [preserve: "[data-owned]"],
+        document: {Volt.Integration.TestPlug, :render, [@fixture_dir]}
+      )
+
+    plug_opts = %{
+      root: @fixture_dir,
+      dev_server: dev_server_opts,
+      morph_dev_server: morph_opts,
+      push_dev_server: push_opts
+    }
 
     {:ok, server} =
       Bandit.start_link(
@@ -415,6 +505,149 @@ defmodule Volt.Integration.HMRTest do
       GenServer.stop(watcher)
     end
 
+    test "content changes reload only the pages whose HTML changed", %{frame: frame} do
+      # Content lives beside the asset root, as a site's pages and posts do.
+      content_dir = @fixture_dir <> "-content"
+      File.rm_rf!(content_dir)
+      File.mkdir_p!(content_dir)
+      on_exit(fn -> File.rm_rf!(content_dir) end)
+      File.write!(Path.join(content_dir, "first.md"), "first page")
+      File.write!(Path.join(content_dir, "second.md"), "second page")
+
+      {:ok, _} = Frame.goto(frame.guid, url: base_url("/doc/first"), timeout: 10_000)
+      assert {:ok, "1"} = eval_until(frame, "document.body.dataset.loads", "1")
+
+      {:ok, watcher} =
+        Volt.Watcher.start_link(
+          root: @fixture_dir,
+          reload_dirs: [content_dir],
+          name: String.to_atom("volt_integration_doc_#{System.unique_integer([:positive])}")
+        )
+
+      Process.sleep(150)
+
+      # Another page's content: this page revalidates and stays.
+      File.write!(Path.join(content_dir, "second.md"), "second page, edited")
+      Process.sleep(1000)
+      assert {:ok, "1"} = eval_poll(frame, "document.body.dataset.loads")
+
+      assert {:ok, "first page"} =
+               eval_poll(frame, "document.getElementById('content').textContent")
+
+      File.write!(Path.join(content_dir, "first.md"), "first page, edited")
+
+      assert {:ok, "first page, edited"} =
+               eval_until(
+                 frame,
+                 "document.getElementById('content')?.textContent",
+                 "first page, edited"
+               )
+
+      assert {:ok, "2"} = eval_poll(frame, "document.body.dataset.loads")
+
+      GenServer.stop(watcher)
+    end
+
+    test "pages that opt in are patched in place instead of reloaded", %{frame: frame} do
+      content_dir = @fixture_dir <> "-content"
+      File.rm_rf!(content_dir)
+      File.mkdir_p!(content_dir)
+      on_exit(fn -> File.rm_rf!(content_dir) end)
+      File.write!(Path.join(content_dir, "first.md"), "first page")
+
+      {:ok, _} = Frame.goto(frame.guid, url: base_url("/morph/first"), timeout: 10_000)
+      assert {:ok, "1"} = eval_until(frame, "document.body.dataset.loads", "1")
+
+      # State a reload would lose.
+      {:ok, _} = eval_poll(frame, "(window.voltKept = 'kept')")
+
+      {:ok, watcher} =
+        Volt.Watcher.start_link(
+          root: @fixture_dir,
+          reload_dirs: [content_dir],
+          name: String.to_atom("volt_integration_morph_#{System.unique_integer([:positive])}")
+        )
+
+      Process.sleep(150)
+      File.write!(Path.join(content_dir, "first.md"), "first page, edited")
+
+      assert {:ok, "first page, edited"} =
+               eval_until(
+                 frame,
+                 "document.getElementById('content')?.textContent",
+                 "first page, edited"
+               )
+
+      assert {:ok, "kept"} = eval_poll(frame, "window.voltKept")
+      assert {:ok, "1"} = eval_poll(frame, "document.body.dataset.loads")
+
+      # The patched page revalidates against its new HTML.
+      File.write!(Path.join(content_dir, "first.md"), "first page, edited twice")
+
+      assert {:ok, "first page, edited twice"} =
+               eval_until(
+                 frame,
+                 "document.getElementById('content')?.textContent",
+                 "first page, edited twice"
+               )
+
+      assert {:ok, "kept"} = eval_poll(frame, "window.voltKept")
+
+      GenServer.stop(watcher)
+    end
+
+    test "the server pushes what it changed to a page it keeps a render of", %{frame: frame} do
+      content_dir = @fixture_dir <> "-content"
+      File.rm_rf!(content_dir)
+      File.mkdir_p!(content_dir)
+      on_exit(fn -> File.rm_rf!(content_dir) end)
+      File.write!(Path.join(content_dir, "page.md"), "first|1|en|old description")
+
+      {:ok, _} = Frame.goto(frame.guid, url: base_url("/push/page"), timeout: 10_000)
+      assert {:ok, "1"} = eval_until(frame, "document.body.dataset.loads", "1")
+      {:ok, _} = eval_poll(frame, "(window.voltKept = 'kept')")
+
+      # The page requests nothing more: what changed arrives over the websocket.
+      {:ok, _} =
+        eval_poll(
+          frame,
+          "(window.voltFetches = 0, window.fetch = ((f) => (...a) => (window.voltFetches++, f(...a)))(window.fetch), 0)"
+        )
+
+      {:ok, watcher} =
+        Volt.Watcher.start_link(
+          root: @fixture_dir,
+          reload_dirs: [content_dir],
+          name: String.to_atom("volt_integration_push_#{System.unique_integer([:positive])}")
+        )
+
+      Process.sleep(150)
+      File.write!(Path.join(content_dir, "page.md"), "second|2|ru|new description")
+
+      assert {:ok, "second"} =
+               eval_until(frame, "document.getElementById('content')?.textContent", "second")
+
+      # The owner of the element re-rendered it from the props the server changed.
+      assert {:ok, "props:2"} =
+               eval_until(frame, "document.getElementById('owned')?.textContent", "props:2")
+
+      # Attributes the server changed are applied; one a script set stays.
+      assert {:ok, "ru"} = eval_poll(frame, "document.documentElement.lang")
+      assert {:ok, "dark"} = eval_poll(frame, "document.documentElement.dataset.theme")
+
+      assert {:ok, "new description"} =
+               eval_poll(frame, "document.querySelector('meta[name=description]').content")
+
+      assert {:ok, 1} =
+               eval_poll(frame, "document.querySelectorAll('meta[name=description]').length")
+
+      assert {:ok, "kept"} = eval_poll(frame, "window.voltKept")
+      assert {:ok, "1"} = eval_poll(frame, "document.body.dataset.loads")
+      assert {:ok, 0} = eval_poll(frame, "window.voltFetches")
+
+      GenServer.stop(watcher)
+    end
+
     test "non-accepted module updates trigger a full reload", %{frame: frame} do
       write_fixture("full_reload.ts", """
       const count = Number(sessionStorage.getItem('voltReloadCount') ?? '0') + 1
diff --git a/test/volt/integration/phoenix_example_test.exs b/test/volt/integration/phoenix_example_test.exs
index 5cb71ea..d99d777 100644
--- a/test/volt/integration/phoenix_example_test.exs
+++ b/test/volt/integration/phoenix_example_test.exs
@@ -146,6 +146,7 @@ defmodule Volt.Integration.PhoenixExampleBuildTest do
 
     File.rm_rf!(Path.join(@outdir, "js"))
     File.rm_rf!(Path.join(@outdir, "css"))
+    File.rm(Path.join(@outdir, "manifest.json"))
 
     {output, status} =
       System.cmd("mix", ["volt.build", "--tailwind", "--hash", "--no-minify"],
@@ -179,22 +180,19 @@ defmodule Volt.Integration.PhoenixExampleBuildTest do
   end
 
   test "produces valid manifest", %{build_status: 0} do
-    manifest = @outdir |> Path.join("js/manifest.json") |> File.read!() |> Jason.decode!()
+    manifest = manifest()
 
     assert Map.has_key?(manifest, "app.js")
-    assert manifest["app.js"]["file"] =~ ~r/^app-[a-f0-9]{8}\.js$/
-  end
-
-  test "produces valid Tailwind manifest", %{build_status: 0} do
-    manifest = @outdir |> Path.join("css/manifest.json") |> File.read!() |> Jason.decode!()
-
+    assert manifest["app.js"]["file"] =~ ~r|^js/app-[a-f0-9]{8}\.js$|
     assert Map.has_key?(manifest, "app.css")
-    assert manifest["app.css"]["file"] =~ ~r/^app-[a-f0-9]{8}\.css$/
+    assert manifest["app.css"]["file"] =~ ~r|^css/app-[a-f0-9]{8}\.css$|
+    refute File.exists?(Path.join(@outdir, "js/manifest.json"))
+    refute File.exists?(Path.join(@outdir, "css/manifest.json"))
   end
 
   test "produces Tailwind CSS with utility classes from heex templates", %{build_status: 0} do
-    manifest = @outdir |> Path.join("css/manifest.json") |> File.read!() |> Jason.decode!()
-    css = File.read!(Path.join([@outdir, "css", manifest["app.css"]["file"]]))
+    manifest = manifest()
+    css = File.read!(Path.join(@outdir, manifest["app.css"]["file"]))
 
     assert css =~ "rounded-2xl"
     assert css =~ "bg-amber-600"
@@ -202,17 +200,17 @@ defmodule Volt.Integration.PhoenixExampleBuildTest do
   end
 
   test "produces Tailwind CSS with Phoenix colocated CSS", %{build_status: 0} do
-    manifest = @outdir |> Path.join("css/manifest.json") |> File.read!() |> Jason.decode!()
-    css = File.read!(Path.join([@outdir, "css", manifest["app.css"]["file"]]))
+    manifest = manifest()
+    css = File.read!(Path.join(@outdir, manifest["app.css"]["file"]))
 
     assert css =~ ".colocated-card"
     assert css =~ "oklch(98.7% .022 95.277)"
   end
 
   test "generates sourcemap", %{build_status: 0} do
-    manifest = @outdir |> Path.join("js/manifest.json") |> File.read!() |> Jason.decode!()
+    manifest = manifest()
     map_path = manifest["app.js"]["file"] <> ".map"
-    map = [@outdir, "js", map_path] |> Path.join() |> File.read!() |> Jason.decode!()
+    map = [@outdir, map_path] |> Path.join() |> File.read!() |> Jason.decode!()
 
     assert map["version"] == 3
   end
@@ -234,7 +232,11 @@ defmodule Volt.Integration.PhoenixExampleBuildTest do
   end
 
   defp js_path do
-    manifest = @outdir |> Path.join("js/manifest.json") |> File.read!() |> Jason.decode!()
-    Path.join([@outdir, "js", manifest["app.js"]["file"]])
+    manifest = manifest()
+    Path.join(@outdir, manifest["app.js"]["file"])
+  end
+
+  defp manifest do
+    @outdir |> Path.join("manifest.json") |> File.read!() |> Jason.decode!()
   end
 end
diff --git a/test/volt/integration/session_test.exs b/test/volt/integration/session_test.exs
new file mode 100644
index 0000000..eb2a574
--- /dev/null
+++ b/test/volt/integration/session_test.exs
@@ -0,0 +1,91 @@
+defmodule Volt.Integration.SessionTest do
+  use ExUnit.Case, async: false
+
+  @moduletag :integration
+  @moduletag :tmp_dir
+
+  test "real filesystem edits update only their session", %{tmp_dir: root} do
+    sessions =
+      for label <- ["first", "second"] do
+        directory = Path.join(root, label)
+        File.mkdir_p!(directory)
+        source = Path.join(directory, "app.css")
+        dependency = Path.join(directory, "theme.css")
+        File.write!(source, "@import './theme.css';")
+        File.write!(dependency, ".#{label} { color: red }")
+        session = make_ref()
+
+        supervisor =
+          start_supervised!(
+            {Volt.Dev.Session.Supervisor,
+             identity: session,
+             watcher: [
+               root: directory,
+               session: session,
+               name: nil,
+               tailwind: true,
+               tailwind_css: source,
+               tailwind_sources: [],
+               tailwind_url: "/assets/site.css"
+             ]},
+            id: session
+          )
+
+        config = %{
+          Volt.DevServer.init(
+            root: directory,
+            watch: false,
+            session: session,
+            session_supervisor: supervisor
+          )
+          | stylesheet_url: "/assets/site.css",
+            stylesheet_source: source
+        }
+
+        {session, supervisor, dependency, config}
+      end
+
+    [{first, _, dependency, config}, {second, _, _, other_config}] = sessions
+    parent = self()
+
+    subscribers =
+      for session <- [first, second] do
+        spawn_link(fn ->
+          Registry.register(Volt.HMR.Registry, Volt.HMR.Channel.key(session), nil)
+          send(parent, {:ready, self()})
+
+          receive do
+            {:check, caller} ->
+              send(caller, {:mailbox, session, Process.info(self(), :messages)})
+
+            {:volt_hmr, type, payload} ->
+              send(parent, {:notification, session, type, payload})
+
+              receive do
+                :stop -> :ok
+              end
+          end
+        end)
+      end
+
+    on_exit(fn -> Enum.each(subscribers, &Process.exit(&1, :kill)) end)
+
+    for pid <- subscribers do
+      assert_receive {:ready, ^pid}
+    end
+
+    before_other = Plug.Test.conn(:get, "/assets/site.css") |> Volt.DevServer.call(other_config)
+    File.write!(dependency, ".first { color: blue }")
+    assert_receive {:notification, ^first, :update, %{changes: [:style]}}, 10_000
+    response = Plug.Test.conn(:get, "/assets/site.css") |> Volt.DevServer.call(config)
+    assert response.status == 200
+    assert response.resp_body =~ "blue"
+    after_other = Plug.Test.conn(:get, "/assets/site.css") |> Volt.DevServer.call(other_config)
+    assert after_other.resp_body == before_other.resp_body
+    [first_subscriber, second_subscriber] = subscribers
+    send(second_subscriber, {:check, self()})
+    assert_receive {:mailbox, ^second, {:messages, []}}
+    refute_received {:notification, ^second, _, _}
+    send(first_subscriber, :stop)
+  end
+end
diff --git a/test/volt/js/discovery_test.exs b/test/volt/js/discovery_test.exs
new file mode 100644
index 0000000..7e8d293
--- /dev/null
+++ b/test/volt/js/discovery_test.exs
@@ -0,0 +1,70 @@
+defmodule Volt.JS.DiscoveryTest do
+  use ExUnit.Case, async: false
+
+  alias Volt.JS.Discovery
+
+  setup do
+    tmp_dir =
+      Path.expand(
+        "volt-js-discovery-#{System.unique_integer([:positive])}",
+        System.tmp_dir!()
+      )
+
+    original_env =
+      Map.new([:format, :lint, :root, :sources, :ignore], fn key ->
+        {key, Application.fetch_env(:volt, key)}
+      end)
+
+    File.mkdir_p!(Path.join(tmp_dir, "format"))
+    File.mkdir_p!(Path.join(tmp_dir, "lint"))
+    File.write!(Path.join(tmp_dir, "format/source.ts"), "const formatted = true")
+    File.write!(Path.join(tmp_dir, "lint/source.ts"), "const linted = true")
+
+    on_exit(fn ->
+      Enum.each(original_env, fn {key, value} -> restore_env(key, value) end)
+      File.rm_rf!(tmp_dir)
+    end)
+
+    %{tmp_dir: tmp_dir}
+  end
+
+  test "discovers tool-specific source sets", %{tmp_dir: tmp_dir} do
+    write_formatter!(tmp_dir, volt: [root: tmp_dir, sources: ["format/**/*.ts"], ignore: []])
+
+    Application.put_env(:volt, :lint,
+      root: tmp_dir,
+      sources: ["lint/**/*.ts"],
+      ignore: []
+    )
+
+    File.cd!(tmp_dir, fn ->
+      assert Discovery.format_files() == [Path.join(tmp_dir, "format/source.ts")]
+      assert Discovery.files(tool: :lint) == [Path.join(tmp_dir, "lint/source.ts")]
+    end)
+  end
+
+  test "formatting uses the build source set without .formatter.exs options", %{tmp_dir: tmp_dir} do
+    Application.put_env(:volt, :format, :esm)
+    Application.put_env(:volt, :root, tmp_dir)
+    Application.put_env(:volt, :sources, ["format/**/*.ts"])
+    Application.put_env(:volt, :ignore, [])
+
+    Application.put_env(:volt, :lint,
+      root: tmp_dir,
+      sources: ["lint/**/*.ts"],
+      ignore: []
+    )
+
+    File.cd!(tmp_dir, fn ->
+      assert Discovery.format_files() == [Path.join(tmp_dir, "format/source.ts")]
+      assert Discovery.files(tool: :lint) == [Path.join(tmp_dir, "lint/source.ts")]
+    end)
+  end
+
+  defp write_formatter!(dir, opts) do
+    File.write!(Path.join(dir, ".formatter.exs"), inspect(opts))
+  end
+
+  defp restore_env(key, :error), do: Application.delete_env(:volt, key)
+  defp restore_env(key, {:ok, value}), do: Application.put_env(:volt, key, value)
+end
diff --git a/test/volt/js/format_test.exs b/test/volt/js/format_test.exs
new file mode 100644
index 0000000..a0cd616
--- /dev/null
+++ b/test/volt/js/format_test.exs
@@ -0,0 +1,61 @@
+defmodule Volt.JS.FormatTest do
+  use ExUnit.Case, async: false
+
+  alias Volt.JS.Format
+
+  setup do
+    original_config = Application.fetch_env(:volt, :format)
+
+    on_exit(fn ->
+      case original_config do
+        :error -> Application.delete_env(:volt, :format)
+        {:ok, config} -> Application.put_env(:volt, :format, config)
+      end
+    end)
+  end
+
+  test "load_config/1 reads formatter options from the :volt key of .formatter.exs" do
+    formatter_opts = [
+      plugins: [Volt.Formatter],
+      volt: [
+        root: ".",
+        sources: ["priv/ts/**/*.ts"],
+        ignore: ["vendor/**"],
+        semi: false,
+        print_width: 100
+      ]
+    ]
+
+    assert Format.load_config(formatter_opts) == [semi: false, print_width: 100]
+
+    assert Format.discovery_config(formatter_opts) == [
+             root: ".",
+             sources: ["priv/ts/**/*.ts"],
+             ignore: ["vendor/**"]
+           ]
+  end
+
+  test "load_config/1 falls back to JSON config files without a :volt key" do
+    assert Format.load_config(plugins: [Volt.Formatter]) == Format.load_json_config()
+  end
+
+  test "load_config/0 reads the project's .formatter.exs" do
+    assert Format.load_config()[:semi] == false
+  end
+
+  test "load_config/1 is unaffected by the build output format" do
+    Application.put_env(:volt, :format, :esm)
+
+    assert Format.load_config(volt: [semi: false]) == [semi: false]
+  end
+
+  test "formatter options under config :volt, :format are rejected with guidance" do
+    Application.put_env(:volt, :format, semi: false)
+
+    assert_raise ArgumentError, ~r/Move them to the `:volt` key of \.formatter\.exs/, fn ->
+      Format.load_config(volt: [])
+    end
+
+    assert_raise ArgumentError, ~r/\.formatter\.exs/, fn -> Volt.Config.build() end
+  end
+end
diff --git a/test/volt/js/lint/config_test.exs b/test/volt/js/lint/config_test.exs
new file mode 100644
index 0000000..3ca4a52
--- /dev/null
+++ b/test/volt/js/lint/config_test.exs
@@ -0,0 +1,91 @@
+defmodule Volt.JS.Lint.ConfigTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.JS.Lint.Config
+
+  test "merges all matching overrides in order and resolves enabled environments" do
+    config =
+      Config.new(
+        [
+          rules: %{"correctness" => :deny, "unicorn/no-null" => :deny},
+          env: ["browser"],
+          globals: %{"shared" => :readonly, "retained" => :readonly},
+          overrides: [
+            %{
+              files: ["scripts/**/*.{js,ts}", "build.js"],
+              env: %{"browser" => false, "node" => true},
+              globals: %{"shared" => :writable},
+              rules: %{"unicorn/no-null" => :allow}
+            },
+            [
+              files: ["scripts/release.*"],
+              env: ["mocha"],
+              globals: %{"shared" => :off},
+              rules: %{"unicorn/no-null" => :warn}
+            ]
+          ]
+        ],
+        "assets"
+      )
+
+    options = Config.options(config, "assets/scripts/release.ts")
+    assert options[:rules] == %{"correctness" => :deny, "unicorn/no-null" => :warn}
+    assert Enum.sort(options[:env]) == ["mocha", "node"]
+    assert options[:globals] == %{"shared" => :off, "retained" => :readonly}
+    assert options[:plugins] == ["typescript"]
+    assert Config.options(config, "assets/build.js")[:rules]["unicorn/no-null"] == :allow
+    assert Config.options(config, "assets/app.js")[:rules]["unicorn/no-null"] == :deny
+  end
+
+  test "uses the lint root, handles absolute paths, and never matches outside the root" do
+    config =
+      Config.new(
+        [
+          root: ".",
+          overrides: [%{files: ["./assets/**/*.js"], rules: %{"no-debugger" => :allow}}]
+        ],
+        "other"
+      )
+
+    relative = Config.options(config, "assets/nested/file.js")
+    assert relative[:rules] == %{"no-debugger" => :allow}
+    assert relative == Config.options(config, Path.expand("assets/nested/file.js"))
+    assert Config.options(config, "elsewhere/file.js")[:rules] == %{}
+
+    scoped =
+      Config.new(
+        [overrides: [%{files: ["**/*.js"], rules: %{"no-debugger" => :allow}}]],
+        "assets"
+      )
+
+    assert Config.options(scoped, "assets-other/file.js")[:rules] == %{}
+    assert Config.options(scoped, "assets/../file.js")[:rules] == %{}
+  end
+
+  test "matches already-discovered hidden files without expanding the filesystem" do
+    config =
+      Config.new([overrides: [%{files: ["**/*.js"], env: ["node"]}]], "hidden/.worktree/assets")
+
+    assert Config.options(config, "hidden/.worktree/assets/.generated/build.js")[:env] == ["node"]
+  end
+
+  test "requires scoped globs and rejects unsupported override settings" do
+    for files <- [[], "*.js", [123], ["../*.js"], [Path.expand("*.js")]] do
+      assert_raise ArgumentError, fn -> Config.new([overrides: [%{files: files}]], "assets") end
+    end
+
+    assert_raise ArgumentError, ~r/unsupported lint override keys/, fn ->
+      Config.new([overrides: [%{files: ["*.js"], plugins: ["node"]}]], "assets")
+    end
+
+    for config <- [[plugins: [:react]], [env: [:browser]], [globals: %{jQuery: :readonly}]] do
+      assert_raise ArgumentError, ~r/names must be strings/, fn ->
+        Config.new(config, "assets")
+      end
+    end
+
+    assert_raise GlobEx.CompileError, fn ->
+      Config.new([overrides: [%{files: ["{broken"]}]], "assets")
+    end
+  end
+end
diff --git a/test/volt/js/lint/tsconfig_overlay_test.exs b/test/volt/js/lint/tsconfig_overlay_test.exs
new file mode 100644
index 0000000..bfeb21e
--- /dev/null
+++ b/test/volt/js/lint/tsconfig_overlay_test.exs
@@ -0,0 +1,72 @@
+defmodule Volt.JS.Lint.TSConfigOverlayTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.JS.Lint.TSConfigOverlay
+
+  @moduletag :tmp_dir
+
+  defp write!(root, path, content) do
+    path = Path.join(root, path)
+    File.mkdir_p!(Path.dirname(path))
+    File.write!(path, content)
+    path
+  end
+
+  test "adds virtual modules to the project of the nearest tsconfig", %{tmp_dir: root} do
+    original = """
+    {
+      // comments and trailing commas are allowed in a tsconfig
+      "compilerOptions": { "paths": { "@/*": ["./assets/js/*"] }, },
+      "include": ["assets/js/**/*.ts"],
+    }
+    """
+
+    tsconfig = write!(root, "tsconfig.json", original)
+    first = Path.join(root, "lib/app_web/Tally.vue.script0.ts")
+    second = Path.join(root, "assets/js/Card.vue.script0.ts")
+
+    overrides = TSConfigOverlay.overrides([first, second])
+
+    # The original is carried unchanged beside the tsconfig that replaces it.
+    assert overrides[Path.join(root, "tsconfig.volt-base.json")] == original
+
+    assert Jason.decode!(overrides[tsconfig]) == %{
+             "extends" => "./tsconfig.volt-base.json",
+             "files" => [second, first]
+           }
+  end
+
+  test "keeps the files the original names, which `files` would replace", %{tmp_dir: root} do
+    tsconfig = write!(root, "tsconfig.json", ~s({ files: ["src/main.ts", "./env.d.ts"] }))
+    virtual = Path.join(root, "src/App.vue.script0.ts")
+
+    assert %{"files" => ["src/main.ts", "./env.d.ts", ^virtual]} =
+             TSConfigOverlay.overrides([virtual])[tsconfig] |> Jason.decode!()
+  end
+
+  test "spells out the default include a tsconfig without one relies on", %{tmp_dir: root} do
+    tsconfig = write!(root, "tsconfig.json", ~s({ "compilerOptions": { "strict": true } }))
+    virtual = Path.join(root, "App.vue.script0.ts")
+
+    assert %{"include" => ["**/*"], "files" => [^virtual]} =
+             TSConfigOverlay.overrides([virtual])[tsconfig] |> Jason.decode!()
+  end
+
+  test "uses the nearest tsconfig for each virtual module", %{tmp_dir: root} do
+    outer = write!(root, "tsconfig.json", ~s({ "include": ["**/*"] }))
+    inner = write!(root, "assets/tsconfig.json", ~s({ "include": ["**/*"] }))
+    in_lib = Path.join(root, "lib/Page.vue.script0.ts")
+    in_assets = Path.join(root, "assets/js/App.vue.script0.ts")
+
+    overrides = TSConfigOverlay.overrides([in_lib, in_assets])
+
+    assert %{"files" => [^in_lib]} = Jason.decode!(overrides[outer])
+    assert %{"files" => [^in_assets]} = Jason.decode!(overrides[inner])
+  end
+
+  test "leaves virtual modules alone without a readable tsconfig above them", %{tmp_dir: root} do
+    write!(root, "broken/tsconfig.json", "not a config")
+
+    assert TSConfigOverlay.overrides([Path.join(root, "broken/App.vue.script0.ts")]) == %{}
+  end
+end
diff --git a/test/volt/js/package_test.exs b/test/volt/js/package_test.exs
new file mode 100644
index 0000000..841f43e
--- /dev/null
+++ b/test/volt/js/package_test.exs
@@ -0,0 +1,31 @@
+defmodule Volt.JS.PackageTest do
+  use ExUnit.Case, async: true
+
+  describe "linked_dirs/1" do
+    @tag :tmp_dir
+    test "lists the real directories of packages linked from outside node_modules", %{
+      tmp_dir: project
+    } do
+      node_modules = Path.join(project, "node_modules")
+      linked = Path.join(project, "packages/client")
+      scoped = Path.join(project, "packages/scoped")
+      File.mkdir_p!(Path.join(node_modules, "installed"))
+      File.mkdir_p!(Path.join(node_modules, "@scope"))
+      File.mkdir_p!(linked)
+      File.mkdir_p!(scoped)
+      File.ln_s!("../packages/client", Path.join(node_modules, "client"))
+      File.ln_s!("../../packages/scoped", Path.join(node_modules, "@scope/scoped"))
+      # A link inside node_modules, as package managers make for workspaces'
+      # hoisted copies, is not a linked package.
+      File.ln_s!("./installed", Path.join(node_modules, "alias"))
+
+      assert Enum.sort(Volt.JS.Package.linked_dirs(node_modules)) ==
+               Enum.sort([Path.expand(linked), Path.expand(scoped)])
+    end
+
+    test "has nothing to list without node_modules" do
+      assert Volt.JS.Package.linked_dirs(nil) == []
+      assert Volt.JS.Package.linked_dirs("/nonexistent/node_modules") == []
+    end
+  end
+end
diff --git a/test/volt/js/resolver_test.exs b/test/volt/js/resolver_test.exs
index 2592470..1b7dcd2 100644
--- a/test/volt/js/resolver_test.exs
+++ b/test/volt/js/resolver_test.exs
@@ -3,8 +3,9 @@ defmodule Volt.JS.ResolverTest do
 
   describe "resolve/2" do
     test "resolves exact alias" do
-      aliases = %{"@" => "/app/assets/src"}
-      assert {:ok, "/app/assets/src"} = Volt.JS.Resolver.resolve("@", aliases)
+      target = Path.expand("app/assets/src")
+      aliases = %{"@" => target}
+      assert {:ok, ^target} = Volt.JS.Resolver.resolve("@", aliases)
     end
 
     test "resolves alias with subpath" do
diff --git a/test/volt/js/runtime/installer_test.exs b/test/volt/js/runtime/installer_test.exs
index b237826..e29e89b 100644
--- a/test/volt/js/runtime/installer_test.exs
+++ b/test/volt/js/runtime/installer_test.exs
@@ -10,7 +10,19 @@ defmodule Volt.JS.Runtime.InstallerTest do
         "volt-runtime-installer-test-#{System.unique_integer([:positive])}"
       )
 
-    on_exit(fn -> File.rm_rf!(tmp_dir) end)
+    File.mkdir_p!(tmp_dir)
+    original_cache_dir = Application.get_env(:npm, :cache_dir)
+    Application.put_env(:npm, :cache_dir, Path.join(tmp_dir, "npm-cache"))
+
+    on_exit(fn ->
+      File.rm_rf!(tmp_dir)
+
+      if original_cache_dir do
+        Application.put_env(:npm, :cache_dir, original_cache_dir)
+      else
+        Application.delete_env(:npm, :cache_dir)
+      end
+    end)
 
     %{tmp_dir: tmp_dir}
   end
@@ -37,6 +49,94 @@ defmodule Volt.JS.Runtime.InstallerTest do
     assert second["packages"] == %{"left-pad" => "1.3.0"}
   end
 
+  test "installs a package-owned lockfile without resolving", %{tmp_dir: tmp_dir} do
+    package = "volt-locked-only"
+    version = "1.0.0"
+    cache_package!(package, version)
+    source_lock = write_lock!(tmp_dir, %{package => lock_entry(version)})
+    install_dir = Path.join(tmp_dir, "install")
+
+    install =
+      Installer.install!(%{package => version},
+        install_dir: install_dir,
+        lockfile: source_lock
+      )
+
+    assert File.read!(Path.join(install_dir, "npm.lock")) == File.read!(source_lock)
+    assert File.read!(Path.join([install.node_modules, package, "package.json"])) =~ package
+  end
+
+  test "includes package-owned lockfile contents in the install signature", %{tmp_dir: tmp_dir} do
+    package = "volt-locked-signature"
+    version = "1.0.0"
+    cache_package!(package, version)
+    source_lock = write_lock!(tmp_dir, %{package => lock_entry(version)})
+    install_dir = Path.join(tmp_dir, "install")
+
+    Installer.install!(%{package => version}, install_dir: install_dir, lockfile: source_lock)
+    first = read_metadata(install_dir)
+
+    source_lock =
+      write_lock!(tmp_dir, %{package => %{lock_entry(version) | integrity: "sha512-changed"}})
+
+    Installer.install!(%{package => version}, install_dir: install_dir, lockfile: source_lock)
+    second = read_metadata(install_dir)
+
+    assert first["signature"] != second["signature"]
+    assert File.read!(Path.join(install_dir, "npm.lock")) == File.read!(source_lock)
+  end
+
+  test "rejects a package-owned lockfile with a mismatched direct version", %{tmp_dir: tmp_dir} do
+    source_lock = write_lock!(tmp_dir, %{"locked-package" => lock_entry("1.0.0")})
+
+    assert_raise ArgumentError, ~r/version mismatch.*expected 2.0.0, got 1.0.0/, fn ->
+      Installer.install!(%{"locked-package" => "2.0.0"},
+        install_dir: Path.join(tmp_dir, "install"),
+        lockfile: source_lock
+      )
+    end
+  end
+
+  test "rejects an incomplete package-owned dependency graph", %{tmp_dir: tmp_dir} do
+    entry = %{lock_entry("1.0.0") | dependencies: %{"missing-transitive" => "^2.0.0"}}
+    source_lock = write_lock!(tmp_dir, %{"locked-package" => entry})
+
+    assert_raise ArgumentError, ~r/does not satisfy.*missing-transitive@\^2.0.0/, fn ->
+      Installer.install!(%{"locked-package" => "1.0.0"},
+        install_dir: Path.join(tmp_dir, "install"),
+        lockfile: source_lock
+      )
+    end
+  end
+
+  defp cache_package!(name, version) do
+    package_dir = NPM.Cache.package_dir(name, version)
+    File.mkdir_p!(package_dir)
+
+    File.write!(
+      Path.join(package_dir, "package.json"),
+      Jason.encode!(%{name: name, version: version})
+    )
+  end
+
+  defp write_lock!(tmp_dir, lockfile) do
+    path = Path.join(tmp_dir, "source-npm.lock")
+    :ok = NPM.Lockfile.write(lockfile, path)
+    path
+  end
+
+  defp lock_entry(version) do
+    %{
+      version: version,
+      integrity: "sha512-test",
+      tarball: "https://registry.npmjs.org/unused.tgz",
+      dependencies: %{},
+      optional_dependencies: %{},
+      has_install_script: false,
+      nested_dependencies: %{}
+    }
+  end
+
   defp read_metadata(install_dir) do
     install_dir
     |> Path.join("volt-runtime.json")
diff --git a/test/volt/js/runtime/package_set_test.exs b/test/volt/js/runtime/package_set_test.exs
new file mode 100644
index 0000000..38d29c4
--- /dev/null
+++ b/test/volt/js/runtime/package_set_test.exs
@@ -0,0 +1,81 @@
+defmodule Volt.JS.Runtime.PackageSetTest do
+  use ExUnit.Case, async: false
+
+  alias Volt.JS.Runtime.PackageSet
+
+  @runtime_modules [Volt.Plugin.Svelte, Volt.Plugin.Solid, Volt.Tailwind.Loader]
+
+  test "built-in package sets ship exact direct versions in valid npm_ex locks" do
+    Enum.each(@runtime_modules, fn module ->
+      set = module.runtime_package_set()
+      lockfile_path = PackageSet.lockfile_path(set)
+
+      assert File.regular?(lockfile_path)
+      assert NPM.Lockfile.version(lockfile_path) == 1
+      assert {:ok, lockfile} = NPM.Lockfile.read(lockfile_path)
+      assert {:ok, policy} = NPM.Lockfile.read_policy(lockfile_path)
+      assert NPM.Lockfile.policy_matches?(policy)
+
+      Enum.each(set.packages, fn {package, exact_version} ->
+        assert %{version: ^exact_version} = Map.fetch!(lockfile, package)
+      end)
+    end)
+  end
+
+  test "runtime opts cannot replace a package set's packages or lockfile" do
+    set = PackageSet.bundled(:volt, :fixture, %{"fixture" => "1.0.0"})
+
+    opts =
+      PackageSet.runtime_opts(set,
+        packages: %{"other" => "2.0.0"},
+        lockfile: "/tmp/other.lock",
+        bundle: true
+      )
+
+    assert opts[:packages] == %{"fixture" => "1.0.0"}
+    assert opts[:lockfile] == PackageSet.lockfile_path(set)
+    assert opts[:bundle]
+  end
+
+  test "built-in package sets use configured resolution when the bundled lock policy is incompatible" do
+    registry = "https://npm.example.test"
+    env = ~w(NPM_REGISTRY NPM_MIRROR NPM_EX_ALLOWED_REGISTRIES)
+    previous = Map.new(env, &{&1, System.get_env(&1)})
+
+    Enum.each(env, &System.put_env(&1, registry))
+
+    on_exit(fn ->
+      Enum.each(previous, fn
+        {name, nil} -> System.delete_env(name)
+        {name, value} -> System.put_env(name, value)
+      end)
+    end)
+
+    set = Volt.Plugin.Svelte.runtime_package_set()
+    opts = PackageSet.runtime_opts(set)
+
+    assert opts[:packages] == %{"svelte" => "5.56.8"}
+    refute Keyword.has_key?(opts, :lockfile)
+  end
+
+  @tag :integration
+  @tag :tmp_dir
+  test "built-in package sets install their packaged locks without re-resolving", %{
+    tmp_dir: tmp_dir
+  } do
+    Enum.each(@runtime_modules, fn module ->
+      set = module.runtime_package_set()
+      source_lock = PackageSet.lockfile_path(set)
+
+      install =
+        PackageSet.install!(set,
+          install_dir: Path.join(tmp_dir, Atom.to_string(set.name)),
+          force: true
+        )
+
+      installed_lock = Path.join(install.install_dir, "npm.lock")
+
+      assert File.read!(installed_lock) == File.read!(source_lock)
+    end)
+  end
+end
diff --git a/test/volt/js/runtime_test.exs b/test/volt/js/runtime_test.exs
index 7bf73d9..deac552 100644
--- a/test/volt/js/runtime_test.exs
+++ b/test/volt/js/runtime_test.exs
@@ -8,7 +8,12 @@ defmodule Volt.JS.RuntimeTest do
     tmp_dir = Path.join(System.tmp_dir!(), Atom.to_string(name))
 
     on_exit(fn ->
-      if pid = GenServer.whereis(name), do: Runtime.stop(pid)
+      try do
+        if pid = GenServer.whereis(name), do: Runtime.stop(pid)
+      catch
+        :exit, _reason -> :ok
+      end
+
       File.rm_rf!(tmp_dir)
     end)
 
@@ -27,4 +32,34 @@ defmodule Volt.JS.RuntimeTest do
       Runtime.ensure!(name: name, packages: %{}, install_dir: second_dir)
     end
   end
+
+  test "named runtimes include package-owned lock contents in their signature", %{
+    name: name,
+    tmp_dir: tmp_dir
+  } do
+    install_dir = Path.join(tmp_dir, "runtime")
+    lockfile = Path.join(tmp_dir, "npm.lock")
+    File.mkdir_p!(tmp_dir)
+    :ok = NPM.Lockfile.write(%{}, lockfile)
+
+    runtime =
+      Runtime.ensure!(
+        name: name,
+        packages: %{},
+        lockfile: lockfile,
+        install_dir: install_dir
+      )
+
+    assert is_pid(runtime.pid)
+    File.write!(lockfile, File.read!(lockfile) <> "\n")
+
+    assert_raise ArgumentError, ~r/already started with different options/, fn ->
+      Runtime.ensure!(
+        name: name,
+        packages: %{},
+        lockfile: lockfile,
+        install_dir: install_dir
+      )
+    end
+  end
 end
diff --git a/test/volt/js/transforms/imports_test.exs b/test/volt/js/transforms/imports_test.exs
index 3634754..07ef1a4 100644
--- a/test/volt/js/transforms/imports_test.exs
+++ b/test/volt/js/transforms/imports_test.exs
@@ -138,7 +138,7 @@ defmodule Volt.JS.Transforms.ImportsTest do
     end
 
     test "raises on parse error" do
-      assert_raise RuntimeError, fn ->
+      assert_raise OXC.Error, ~r"bad.js:1:", fn ->
         Volt.JS.Transforms.Imports.rewrite!("const = ;", "bad.js", fn _ -> :keep end)
       end
     end
diff --git a/test/volt/js/tsconfig_test.exs b/test/volt/js/tsconfig_test.exs
index 9576d15..9ad3e84 100644
--- a/test/volt/js/tsconfig_test.exs
+++ b/test/volt/js/tsconfig_test.exs
@@ -69,6 +69,23 @@ defmodule Volt.JS.TSConfigTest do
       paths = Volt.JS.TSConfig.read_paths(tsconfig_path())
       assert paths["~utils"] =~ "src/utils"
     end
+
+    test "skips mappings that only point at declaration files" do
+      write_tsconfig!(%{
+        "compilerOptions" => %{
+          "paths" => %{
+            "topbar" => ["./types/topbar.d.ts"],
+            "phoenix" => ["./types/phoenix.d.ts", "./vendor/phoenix.js"],
+            "@/*" => ["./src/*"]
+          }
+        }
+      })
+
+      paths = Volt.JS.TSConfig.read_paths(tsconfig_path())
+      refute Map.has_key?(paths, "topbar")
+      assert paths["phoenix"] =~ "vendor/phoenix.js"
+      assert paths["@"] =~ "src"
+    end
   end
 
   defp tsconfig_path, do: Path.join(@fixture_dir, "tsconfig.json")
diff --git a/test/volt/js/vendor_test.exs b/test/volt/js/vendor_test.exs
index d6122c7..7f2b26a 100644
--- a/test/volt/js/vendor_test.exs
+++ b/test/volt/js/vendor_test.exs
@@ -30,6 +30,26 @@ defmodule Volt.JS.VendorTest do
     :ok
   end
 
+  @tag :tmp_dir
+  test "distinct package roots cannot overwrite each other's vendor output", %{tmp_dir: root} do
+    contexts =
+      for name <- ["first", "second"] do
+        modules = Path.join([root, name, "node_modules"])
+        package = Path.join(modules, "same-lib")
+        File.mkdir_p!(package)
+        File.write!(Path.join(package, "package.json"), ~s({"name":"same-lib","main":"index.js"}))
+        File.write!(Path.join(package, "index.js"), "export const value = '#{name}'")
+        assert {:ok, code} = Volt.JS.Vendor.bundle_on_demand("same-lib", modules)
+        {modules, code}
+      end
+
+    [{first, first_code}, {second, second_code}] = contexts
+    assert first_code =~ "first"
+    assert second_code =~ "second"
+    assert {:ok, ^first_code} = Volt.JS.Vendor.read("same-lib", node_modules: first)
+    assert {:ok, ^second_code} = Volt.JS.Vendor.read("same-lib", node_modules: second)
+  end
+
   describe "prebundle/1" do
     test "detects bare imports and bundles them" do
       {:ok, vendor_map} =
@@ -41,13 +61,92 @@ defmodule Volt.JS.VendorTest do
       assert Map.has_key?(vendor_map, "fake-lib")
     end
 
+    test "logs only when packages are bundled, not when the cache is fresh" do
+      opts = [root: Path.join(@fixture_dir, "src"), node_modules: @node_modules]
+
+      assert ExUnit.CaptureLog.capture_log(fn ->
+               Volt.JS.Vendor.prebundle(Keyword.put(opts, :force, true))
+             end) =~
+               "Pre-bundled"
+
+      refute ExUnit.CaptureLog.capture_log(fn -> Volt.JS.Vendor.prebundle(opts) end) =~
+               "Pre-bundled"
+    end
+
+    @tag :tmp_dir
+    test "writes the cache under the project root while the working directory is elsewhere",
+         %{tmp_dir: elsewhere} do
+      # Mix changes the VM's working directory while it compiles a dependency,
+      # as Phoenix's code reloader does during a request.
+      {:ok, vendor_map} =
+        File.cd!(elsewhere, fn ->
+          Volt.JS.Vendor.prebundle(
+            root: Path.join(@fixture_dir, "src"),
+            node_modules: @node_modules,
+            force: true
+          )
+        end)
+
+      assert File.ls!(elsewhere) == []
+
+      for {_specifier, path} <- vendor_map do
+        assert String.starts_with?(path, Volt.Paths.expand("_build"))
+        assert File.regular?(path)
+      end
+
+      assert {:ok, _code} =
+               File.cd!(elsewhere, fn ->
+                 Volt.JS.Vendor.read("fake-lib", node_modules: @node_modules)
+               end)
+    end
+
+    test "an import that resolves to no package does not bundle the others again" do
+      File.write!(
+        Path.join(@fixture_dir, "src/provided.ts"),
+        "import { value } from 'fake-lib'\nimport host from 'provided-by-the-page'\nconsole.log(value, host)"
+      )
+
+      on_exit(fn -> File.rm(Path.join(@fixture_dir, "src/provided.ts")) end)
+      opts = [root: Path.join(@fixture_dir, "src"), node_modules: @node_modules]
+
+      {:ok, vendor_map} = Volt.JS.Vendor.prebundle(Keyword.put(opts, :force, true))
+      assert Map.has_key?(vendor_map, "fake-lib")
+      refute Map.has_key?(vendor_map, "provided-by-the-page")
+
+      refute ExUnit.CaptureLog.capture_log(fn -> Volt.JS.Vendor.prebundle(opts) end) =~
+               "Pre-bundled"
+    end
+
+    test "is not repeated on every request until the sources are said to have changed" do
+      opts = [root: Path.join(@fixture_dir, "src"), node_modules: @node_modules]
+
+      prebundle = fn ->
+        Volt.Dev.Prebundled.ensure(opts, fn -> Volt.JS.Vendor.prebundle(opts) end)
+      end
+
+      Volt.Dev.Prebundled.forget()
+      on_exit(&Volt.Dev.Prebundled.forget/0)
+
+      :ok = prebundle.()
+      [cached] = Path.wildcard("_build/volt/vendor/*/fake-lib.js")
+      File.rm!(cached)
+
+      # Asked again, as on every request: nothing is scanned or bundled.
+      :ok = prebundle.()
+      refute File.exists?(cached)
+
+      Volt.Dev.Prebundled.forget()
+      :ok = prebundle.()
+      assert File.exists?(cached)
+    end
+
     test "caches bundled files on disk" do
       Volt.JS.Vendor.prebundle(
         root: Path.join(@fixture_dir, "src"),
         node_modules: @node_modules
       )
 
-      assert File.regular?("_build/volt/vendor/fake-lib.js")
+      assert [_] = Path.wildcard("_build/volt/vendor/*/fake-lib.js")
     end
 
     test "does not scan into node_modules under the root" do
@@ -126,8 +225,8 @@ defmodule Volt.JS.VendorTest do
       assert Map.has_key?(vendor_map, "editor-a")
       assert Map.has_key?(vendor_map, "editor-b")
 
-      {:ok, editor_a} = Volt.JS.Vendor.read("editor-a")
-      {:ok, editor_b} = Volt.JS.Vendor.read("editor-b")
+      {:ok, editor_a} = Volt.JS.Vendor.read("editor-a", node_modules: @node_modules)
+      {:ok, editor_b} = Volt.JS.Vendor.read("editor-b", node_modules: @node_modules)
 
       assert [chunk] =
                [editor_a, editor_b]
@@ -136,7 +235,7 @@ defmodule Volt.JS.VendorTest do
                |> Enum.uniq()
 
       chunk_specifier = chunk |> String.trim_leading("./") |> String.trim_trailing(".js")
-      {:ok, shared_chunk} = Volt.JS.Vendor.read(chunk_specifier)
+      {:ok, shared_chunk} = Volt.JS.Vendor.read(chunk_specifier, node_modules: @node_modules)
       assert shared_chunk =~ "singleton"
     end
 
@@ -185,7 +284,11 @@ defmodule Volt.JS.VendorTest do
                  plugins: [BrokenSyntheticVendor]
                )
 
-      assert {:ok, ^stable} = Volt.JS.Vendor.read("unstable-lib")
+      assert {:ok, ^stable} =
+               Volt.JS.Vendor.read("unstable-lib",
+                 node_modules: @node_modules,
+                 plugins: [StableSyntheticVendor]
+               )
     end
 
     test "rebuilds cached synthetic entries when plugin prebundle source changes" do
@@ -231,7 +334,7 @@ defmodule Volt.JS.VendorTest do
         node_modules: @node_modules
       )
 
-      {:ok, code} = Volt.JS.Vendor.read("fake-lib")
+      {:ok, code} = Volt.JS.Vendor.read("fake-lib", node_modules: @node_modules)
       assert code =~ "greet"
       refute code =~ "module.exports"
     end
@@ -252,7 +355,10 @@ defmodule Volt.JS.VendorTest do
         )
 
       assert Map.has_key?(vendor_map, "react")
-      {:ok, react_proxy} = Volt.JS.Vendor.read("react")
+
+      {:ok, react_proxy} =
+        Volt.JS.Vendor.read("react", node_modules: @node_modules, plugins: [Volt.Plugin.React])
+
       assert react_proxy =~ ~r/export \{[^}]*act/s
     end
 
@@ -285,8 +391,14 @@ defmodule Volt.JS.VendorTest do
       assert Map.has_key?(vendor_map, "react")
       assert Map.has_key?(vendor_map, "react-using-dom")
 
-      {:ok, react_proxy} = Volt.JS.Vendor.read("react")
-      {:ok, react_using_dom} = Volt.JS.Vendor.read("react-using-dom")
+      {:ok, react_proxy} =
+        Volt.JS.Vendor.read("react", node_modules: @node_modules, plugins: [Volt.Plugin.React])
+
+      {:ok, react_using_dom} =
+        Volt.JS.Vendor.read("react-using-dom",
+          node_modules: @node_modules,
+          plugins: [Volt.Plugin.React]
+        )
 
       assert [shared_chunk] =
                [react_proxy, react_using_dom]
@@ -295,7 +407,12 @@ defmodule Volt.JS.VendorTest do
                |> Enum.uniq()
 
       chunk_specifier = shared_chunk |> String.trim_leading("./") |> String.trim_trailing(".js")
-      {:ok, shared_code} = Volt.JS.Vendor.read(chunk_specifier)
+
+      {:ok, shared_code} =
+        Volt.JS.Vendor.read(chunk_specifier,
+          node_modules: @node_modules,
+          plugins: [Volt.Plugin.React]
+        )
 
       assert react_using_dom =~ "flushSync"
       assert shared_code =~ "domSingleton"
@@ -319,7 +436,13 @@ defmodule Volt.JS.VendorTest do
         )
 
       assert Map.has_key?(vendor_map, "react-dom")
-      {:ok, react_dom_proxy} = Volt.JS.Vendor.read("react-dom")
+
+      {:ok, react_dom_proxy} =
+        Volt.JS.Vendor.read("react-dom",
+          node_modules: @node_modules,
+          plugins: [Volt.Plugin.React]
+        )
+
       assert react_dom_proxy =~ ~r/export \{[^}]*flushSync/s
     end
   end
@@ -368,7 +491,7 @@ defmodule Volt.JS.VendorTest do
 
       assert Map.has_key?(vendor_map, "cjs-lib")
 
-      {:ok, code} = Volt.JS.Vendor.read("cjs-lib")
+      {:ok, code} = Volt.JS.Vendor.read("cjs-lib", node_modules: @node_modules)
       assert code =~ "export"
       refute String.starts_with?(code, "\"use strict\";(function()")
     end
@@ -414,7 +537,7 @@ defmodule Volt.JS.VendorTest do
           node_modules: @node_modules
         )
 
-      {:ok, code} = Volt.JS.Vendor.read("conditional-lib")
+      {:ok, code} = Volt.JS.Vendor.read("conditional-lib", node_modules: @node_modules)
       assert code =~ "development"
     end
 
@@ -457,7 +580,7 @@ defmodule Volt.JS.VendorTest do
           node_modules: @node_modules
         )
 
-      {:ok, code} = Volt.JS.Vendor.read("dep-b")
+      {:ok, code} = Volt.JS.Vendor.read("dep-b", node_modules: @node_modules)
       assert code =~ "require_dep_a"
       assert code =~ "exports.b = require_dep_a().a + 1"
     end
@@ -494,7 +617,10 @@ defmodule Volt.JS.VendorTest do
         )
 
       assert Map.has_key?(vendor_map, "hex-lib")
-      {:ok, code} = Volt.JS.Vendor.read("hex-lib")
+
+      {:ok, code} =
+        Volt.JS.Vendor.read("hex-lib", node_modules: @node_modules, resolve_dirs: [@deps_dir])
+
       assert code =~ "from deps"
     end
 
@@ -535,7 +661,13 @@ defmodule Volt.JS.VendorTest do
         )
 
       assert Map.has_key?(vendor_map, "phoenix-colocated/my_app")
-      {:ok, code} = Volt.JS.Vendor.read("phoenix-colocated/my_app")
+
+      {:ok, code} =
+        Volt.JS.Vendor.read("phoenix-colocated/my_app",
+          node_modules: @node_modules,
+          resolve_dirs: [@deps_dir]
+        )
+
       assert code =~ "MyAppWeb.DemoLive.Sortable"
       assert code =~ "colocated hook mounted"
     end
@@ -549,7 +681,7 @@ defmodule Volt.JS.VendorTest do
 
     test "caches the result for subsequent read/1 calls" do
       {:ok, _} = Volt.JS.Vendor.bundle_on_demand("fake-lib", @node_modules)
-      {:ok, code} = Volt.JS.Vendor.read("fake-lib")
+      {:ok, code} = Volt.JS.Vendor.read("fake-lib", node_modules: @node_modules)
       assert code =~ "greet"
     end
 
@@ -583,12 +715,13 @@ defmodule Volt.JS.VendorTest do
         node_modules: @node_modules
       )
 
-      {:ok, code} = Volt.JS.Vendor.read("fake-lib")
+      {:ok, code} = Volt.JS.Vendor.read("fake-lib", node_modules: @node_modules)
       assert code =~ "greet"
     end
 
     test "returns error for missing vendor" do
-      assert {:error, :not_found} = Volt.JS.Vendor.read("nonexistent")
+      assert {:error, :not_found} =
+               Volt.JS.Vendor.read("nonexistent", node_modules: @node_modules)
     end
   end
 
@@ -650,12 +783,15 @@ defmodule Volt.JS.VendorTest do
              ) == url
     end
 
-    test "browser hash changes when lockfile changes" do
-      lockfile = Path.join(@fixture_dir, "package-lock.json")
-      File.write!(lockfile, ~s({"lockfileVersion":1}))
+    # A lockfile is known by its size and modification time, as a package
+    # manager's write changes both.
+    test "browser hash changes when a lockfile changes" do
+      lockfile = Path.join(@fixture_dir, "npm.lock")
+      File.write!(lockfile, ~s({"lockfileVersion":1,"packages":{}}))
       first = Volt.JS.Vendor.browser_hash(node_modules: @node_modules, plugins: [])
 
-      File.write!(lockfile, ~s({"lockfileVersion":2}))
+      File.write!(lockfile, ~s({"lockfileVersion":1,"packages":{"vue":{}}}))
+      File.touch!(lockfile, System.os_time(:second) + 2)
       second = Volt.JS.Vendor.browser_hash(node_modules: @node_modules, plugins: [])
 
       refute first == second
diff --git a/test/volt/npm_test.exs b/test/volt/npm_test.exs
new file mode 100644
index 0000000..3395ec7
--- /dev/null
+++ b/test/volt/npm_test.exs
@@ -0,0 +1,9 @@
+defmodule Volt.NPMTest do
+  use ExUnit.Case, async: true
+
+  test "install!/2 rejects invalid package entries before installation" do
+    assert_raise ArgumentError, ~r/non-empty string names and versions/, fn ->
+      Volt.NPM.install!(%{"package" => ""})
+    end
+  end
+end
diff --git a/test/volt/pipeline_test.exs b/test/volt/pipeline_test.exs
index fc95a01..cf63ee3 100644
--- a/test/volt/pipeline_test.exs
+++ b/test/volt/pipeline_test.exs
@@ -152,6 +152,38 @@ defmodule Volt.PipelineTest do
       {:ok, result} = Volt.Pipeline.compile("App.vue", source)
       assert is_binary(result.css)
     end
+
+    test "returns authored SFC source maps when enabled" do
+      source = """
+      <template><div>{{ message }}</div></template>
+      <script setup>
+      const message = "mapped"
+      </script>
+      """
+
+      {:ok, mapped} = Volt.Pipeline.compile("src/App.vue", source, sourcemap: true)
+      assert is_binary(mapped.sourcemap)
+      assert mapped.sourcemap =~ "src/App.vue"
+
+      {:ok, unmapped} = Volt.Pipeline.compile("src/App.vue", source, sourcemap: false)
+      assert unmapped.sourcemap == nil
+    end
+
+    test "rewrites template assets to imports and reports their dependencies" do
+      source = """
+      <template><img src="./logo.png"><svg><use href="@/icons.svg#check" /></svg></template>
+      """
+
+      {:ok, result} = Volt.Pipeline.compile("src/App.vue", source)
+
+      assert result.code =~ ~s(import _imports_0 from "./logo.png")
+      assert result.code =~ ~s(import _imports_1 from "@/icons.svg")
+      assert result.code =~ ~s(_imports_1 + "#check")
+
+      assert {:ok, imports} = Volt.Plugin.Vue.extract_imports("src/App.vue", source, [])
+      assert {:static, "./logo.png"} in imports.imports
+      assert {:static, "@/icons.svg"} in imports.imports
+    end
   end
 
   describe "compile/3 with Svelte" do
diff --git a/test/volt/plugin/vue_test.exs b/test/volt/plugin/vue_test.exs
new file mode 100644
index 0000000..a1d5328
--- /dev/null
+++ b/test/volt/plugin/vue_test.exs
@@ -0,0 +1,121 @@
+defmodule Volt.Plugin.VueTest do
+  use ExUnit.Case, async: true
+
+  test "template-only SFCs expose a default component" do
+    assert {:ok, result} =
+             Volt.Plugin.Vue.compile(
+               "/fixtures/Only.vue",
+               "<template><button>Widget</button></template>",
+               []
+             )
+
+    assert result.code =~ "export default { render }"
+  end
+
+  describe "embedded_modules/3" do
+    defp script_modules(source) do
+      "Example.vue"
+      |> Volt.Plugin.Vue.embedded_modules(source, [])
+      |> Volt.Plugin.EmbeddedModule.normalize_all()
+      |> Enum.filter(&(&1.type == :script))
+      |> Enum.map(&{&1.extension, String.trim(&1.source)})
+    end
+
+    test "leaves out script blocks that are not JavaScript" do
+      source = """
+      <script setup lang="ts">
+      const n: number = 1
+      </script>
+
+      <script lang="elixir">
+      def total(%{items: items}), do: length(items)
+      </script>
+
+      <template><p>{{ n }}</p></template>
+      """
+
+      assert script_modules(source) == [{".ts", "const n: number = 1"}]
+    end
+
+    test "names script blocks by their JavaScript dialect" do
+      for {lang, extension} <- [
+            {"", ".js"},
+            {~s( lang="js"), ".js"},
+            {~s( lang="jsx"), ".jsx"},
+            {~s( lang="ts"), ".ts"},
+            {~s( lang="tsx"), ".tsx"}
+          ] do
+        source = "<script#{lang}>export default {}</script><template><p /></template>"
+
+        assert script_modules(source) == [{extension, "export default {}"}]
+      end
+    end
+  end
+
+  test "script-bearing scoped components receive their CSS scope on the default export" do
+    for script <- [
+          "<script setup>defineProps(['label'])</script>",
+          "<script>export default { props: ['label'] }</script>"
+        ] do
+      source =
+        script <>
+          "<template><button>{{ label }}</button></template><style scoped>button { color: red }</style>"
+
+      assert {:ok, result} = Volt.Plugin.Vue.compile("/fixtures/Script.vue", source, [])
+      scope = "data-v-" <> Vize.SFC.scope_id("/fixtures/Script.vue")
+      assert result.code =~ "__scopeId = \"#{scope}\""
+      assert result.css =~ scope
+      assert {:ok, _} = OXC.parse(result.code, "component.js")
+      assert is_nil(result.sourcemap)
+    end
+  end
+
+  @tag :tmp_dir
+  test "scope attachment does not capture module bindings and preserves component identity", %{
+    tmp_dir: tmp
+  } do
+    file = "/fixtures/Shadow.vue"
+
+    source = """
+    <script>
+    export const Object = {};
+    export const component = { value: 42 };
+    export default component;
+    </script>
+    <style scoped>p { color: red }</style>
+    """
+
+    assert {:ok, result} = Volt.Plugin.Vue.compile(file, source, [])
+    File.write!(Path.join(tmp, "scoped.js"), result.code)
+
+    File.write!(Path.join(tmp, "assertions.js"), """
+    import scoped, { Object, component } from "./scoped.js";
+    globalThis.observed = {
+      scope: scoped.__scopeId,
+      same: scoped === component,
+      value: scoped.value,
+      untouched: !Object.__scopeId
+    };
+    """)
+
+    runtime = start_supervised!({QuickBEAM, script: Path.join(tmp, "assertions.js")})
+
+    scope = "data-v-" <> Vize.SFC.scope_id(file)
+
+    assert {:ok, %{"scope" => ^scope, "same" => true, "value" => 42, "untouched" => true}} =
+             QuickBEAM.eval(runtime, "globalThis.observed")
+  end
+
+  test "template-only scoped CSS and component use the same scope identity" do
+    file = "/fixtures/Scoped.vue"
+
+    source =
+      "<template><button>Widget</button></template><style scoped>button { color: red }</style>"
+
+    assert {:ok, result} = Volt.Plugin.Vue.compile(file, source, [])
+    scope = "data-v-" <> Vize.SFC.scope_id(file)
+    assert result.code =~ scope
+    assert result.css =~ scope
+    assert result.code =~ "__scopeId"
+  end
+end
diff --git a/test/volt/plugin_runner_test.exs b/test/volt/plugin_runner_test.exs
index d705b3d..88242cd 100644
--- a/test/volt/plugin_runner_test.exs
+++ b/test/volt/plugin_runner_test.exs
@@ -161,7 +161,7 @@ defmodule Volt.PluginRunnerTest do
     end
 
     test "loads embedded modules by query id" do
-      path = Path.join(System.tmp_dir!(), "volt-plugin-runner-card.box")
+      path = Path.expand("volt-plugin-runner-card.box", System.tmp_dir!())
       File.write!(path, "export const value: number = 1")
 
       id =
diff --git a/test/volt/preload_test.exs b/test/volt/preload_test.exs
index 34c3d87..3065ece 100644
--- a/test/volt/preload_test.exs
+++ b/test/volt/preload_test.exs
@@ -37,6 +37,22 @@ defmodule Volt.PreloadTest do
       refute result =~ "lazy-fedcba.js"
     end
 
+    test "resolves cyclic and nested import keys to emitted paths" do
+      manifest = %{
+        "app.js" => %{
+          "file" => "js/app-hash.js",
+          "imports" => ["shared", "missing"],
+          "dynamicImports" => ["lazy"]
+        },
+        "shared" => %{"file" => "js/shared-hash.js", "imports" => ["vendor"]},
+        "vendor" => %{"file" => "js/vendor-hash.js", "imports" => ["shared"]},
+        "lazy" => %{"file" => "js/lazy-hash.js"}
+      }
+
+      assert Volt.Preload.tags(manifest, entry: "app.js", prefix: "https://cdn.example/assets") ==
+               ~s(<link rel="modulepreload" href="https://cdn.example/assets/js/shared-hash.js">\n<link rel="modulepreload" href="https://cdn.example/assets/js/vendor-hash.js">)
+    end
+
     test "joins prefix with URI semantics" do
       manifest = %{"app.js" => "app-abc123.js"}
 
diff --git a/test/volt/priv/vendor_test.exs b/test/volt/priv/vendor_test.exs
new file mode 100644
index 0000000..d408ed3
--- /dev/null
+++ b/test/volt/priv/vendor_test.exs
@@ -0,0 +1,67 @@
+defmodule Volt.Priv.VendorTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.Priv.Vendor
+
+  @moduletag :tmp_dir
+
+  test "keeps the browser modules and declarations the sources reach", %{tmp_dir: tmp_dir} do
+    sources = Path.join(tmp_dir, "priv/ts")
+    node_modules = Path.join(tmp_dir, "install/node_modules")
+
+    write!(sources, %{
+      "app.ts" => """
+      import { widget } from 'kit'
+      import 'kit/extra.js'
+      import { compile } from 'runtime-only'
+      import { local } from './local'
+      """,
+      "local.ts" => "export const local = 1\n"
+    })
+
+    write!(node_modules, %{
+      "kit/package.json" =>
+        Jason.encode!(%{
+          name: "kit",
+          exports: %{
+            "." => %{types: "./types/kit.d.ts", browser: "./kit.js", default: "./node/kit.js"},
+            "./extra.js" => "./extra.js"
+          }
+        }),
+      "kit/LICENSE" => "MIT",
+      "kit/kit.js" => "import { helper } from './helper.js'\nexport const widget = helper\n",
+      "kit/helper.js" => "export const helper = 1\n",
+      "kit/node/kit.js" => "export const widget = 1\n",
+      "kit/extra.js" => "export {}\n",
+      "kit/extra.d.ts" => "export {}\n",
+      "kit/unused.js" => "export {}\n",
+      "kit/kit.js.map" => "{}",
+      "kit/types/kit.d.ts" =>
+        "import type { Policy } from 'policy/lib/index.js'\nexport declare const widget: Policy\n",
+      "@types/policy/package.json" => Jason.encode!(%{name: "@types/policy"}),
+      "@types/policy/lib/index.d.ts" => "export type Policy = string\n",
+      "runtime-only/package.json" => Jason.encode!(%{name: "runtime-only", main: "index.js"}),
+      "runtime-only/index.js" => "export const compile = 1\n"
+    })
+
+    assert Vendor.reachable(sources, %{"kit" => "1.0.0"}, node_modules) == [
+             "@types/policy/lib/index.d.ts",
+             "@types/policy/package.json",
+             "kit/LICENSE",
+             "kit/extra.d.ts",
+             "kit/extra.js",
+             "kit/helper.js",
+             "kit/kit.js",
+             "kit/package.json",
+             "kit/types/kit.d.ts"
+           ]
+  end
+
+  defp write!(root, files) do
+    for {path, contents} <- files do
+      path = Path.join(root, path)
+      File.mkdir_p!(Path.dirname(path))
+      File.write!(path, contents)
+    end
+  end
+end
diff --git a/test/volt/priv_test.exs b/test/volt/priv_test.exs
index e49a4e6..7511fce 100644
--- a/test/volt/priv_test.exs
+++ b/test/volt/priv_test.exs
@@ -15,6 +15,13 @@ defmodule Volt.PrivTest do
     assert code =~ "const proto"
   end
 
+  test "renders TypeScript without compiling it" do
+    code = Volt.Priv.render!(@support_modules, "test/browser.ts")
+
+    assert code =~ "type BrowserPayload"
+    assert code =~ "src: string"
+  end
+
   test "emits browser JavaScript from TypeScript support modules" do
     code = Volt.Priv.js!(@support_modules, "client/hmr.ts")
 
@@ -22,6 +29,18 @@ defmodule Volt.PrivTest do
     refute code =~ "type "
   end
 
+  test "invalidates cached support modules when their source changes" do
+    relative = "test/cache-#{System.unique_integer([:positive])}.ts"
+    path = Volt.Priv.path(@support_modules, relative)
+    on_exit(fn -> File.rm(path) end)
+
+    File.write!(path, "export const value = 1;")
+    assert Volt.Priv.js!(@support_modules, relative) =~ "value = 1"
+
+    File.write!(path, "export const value = 2;")
+    assert Volt.Priv.js!(@support_modules, relative) =~ "value = 2"
+  end
+
   test "binds JavaScript literals and rewrites support imports" do
     code =
       Volt.Priv.js!(
@@ -37,8 +56,20 @@ defmodule Volt.PrivTest do
     refute code =~ "$mod_url"
   end
 
+  test "splices multiple statements into support modules" do
+    code =
+      Volt.Priv.js!(@support_modules, "test/entry.ts", [],
+        splices: [imports: ~s|import "./setup.ts"; import "./test.ts";|]
+      )
+
+    assert code =~ ~s(import "./setup.ts")
+    assert code =~ ~s(import "./test.ts")
+    refute code =~ "$imports"
+  end
+
   test "rejects paths outside priv" do
     assert_raise ArgumentError, fn -> Volt.Priv.path(@support_modules, "../secret.ts") end
-    assert_raise ArgumentError, fn -> Volt.Priv.path(@support_modules, "/tmp/secret.ts") end
+    outside = Path.expand("secret.ts", System.tmp_dir!())
+    assert_raise ArgumentError, fn -> Volt.Priv.path(@support_modules, outside) end
   end
 end
diff --git a/test/volt/public_dir_test.exs b/test/volt/public_dir_test.exs
new file mode 100644
index 0000000..7a4d92e
--- /dev/null
+++ b/test/volt/public_dir_test.exs
@@ -0,0 +1,39 @@
+defmodule Volt.PublicDirTest do
+  use ExUnit.Case, async: true
+
+  alias Volt.Builder.{Artifact, Plan}
+  @moduletag :tmp_dir
+
+  test "explicit public root prefixes nested compiled outputs", %{tmp_dir: root} do
+    public = Path.join(root, "public")
+    File.mkdir_p!(public)
+    File.write!(Path.join(public, "robots.txt"), "public")
+    {:ok, plan} = Plan.new([%Artifact{file: "app.js", content: "script"}])
+    output = Path.join(root, "dist/assets")
+    static = Path.join(root, "dist")
+    assert {:ok, ^static, combined} = Volt.PublicDir.prepare_output(plan, output, public, static)
+    assert Enum.map(combined.artifacts, & &1.file) == ["assets/app.js", "robots.txt"]
+    refute File.exists?(static)
+  end
+
+  test "can represent the lower-level parent-directory contract", %{tmp_dir: root} do
+    {:ok, plan} = Plan.new([%Artifact{file: "app.js", content: "script"}])
+
+    assert {:ok, ^root, combined} =
+             Volt.PublicDir.prepare_output(plan, Path.join(root, "assets"), nil, root)
+
+    assert [%Artifact{file: "assets/app.js"}] = combined.artifacts
+  end
+
+  test "rejects unrelated public destinations", %{tmp_dir: root} do
+    {:ok, plan} = Plan.new([])
+
+    assert {:error, {:invalid_publication_root, _, _}} =
+             Volt.PublicDir.prepare_output(
+               plan,
+               Path.join(root, "assets"),
+               nil,
+               Path.join(root, "other")
+             )
+  end
+end
diff --git a/test/volt/tailwind/artifact_test.exs b/test/volt/tailwind/artifact_test.exs
new file mode 100644
index 0000000..0e0a593
--- /dev/null
+++ b/test/volt/tailwind/artifact_test.exs
@@ -0,0 +1,16 @@
+defmodule Volt.Tailwind.ArtifactTest do
+  use ExUnit.Case, async: true
+
+  @moduletag :tmp_dir
+
+  test "replaces the stylesheet without leaving temporary files", %{tmp_dir: tmp} do
+    assert :ok = Volt.Tailwind.Artifact.write(tmp, "site", "first")
+    assert :ok = Volt.Tailwind.Artifact.write(tmp, "site", "second")
+
+    assert File.read!(Path.join(tmp, "site.css")) == "second"
+    assert File.ls!(tmp) == ["site.css"]
+  end
+
+  test "accepts disabled output",
+    do: assert(:ok = Volt.Tailwind.Artifact.write(nil, "site", "css"))
+end
diff --git a/test/volt/tailwind/build_test.exs b/test/volt/tailwind/build_test.exs
new file mode 100644
index 0000000..a76925f
--- /dev/null
+++ b/test/volt/tailwind/build_test.exs
@@ -0,0 +1,124 @@
+defmodule Volt.Tailwind.BuildTest do
+  use ExUnit.Case, async: false
+
+  @moduletag :tmp_dir
+
+  test "nested stylesheet assets retain their origins", %{tmp_dir: root} do
+    for directory <- ["a", "b"] do
+      File.mkdir_p!(Path.join(root, directory))
+      File.write!(Path.join([root, directory, "logo.svg"]), "<svg>#{directory}</svg>")
+
+      File.write!(
+        Path.join([root, directory, "theme.css"]),
+        ".#{directory} { background: url('./logo.svg?v=1#mark') }"
+      )
+    end
+
+    File.write!(Path.join(root, "a/font.woff2"), <<0, 1, 2, 3>>)
+
+    File.write!(
+      Path.join(root, "a/font.css"),
+      "@font-face { font-family: Test; src: url('./font.woff2') }"
+    )
+
+    css = Path.join(root, "style.css")
+
+    File.write!(
+      css,
+      "@import 'tailwindcss' source(none); @import './a/theme.css'; @import './b/theme.css'; @import './a/font.css';"
+    )
+
+    config = Volt.Config.Tailwind.new(css: css)
+
+    assert {:ok, result, plan} =
+             Volt.Tailwind.Build.prepare(config,
+               outdir: Path.join(root, "output"),
+               root: root,
+               hash: false,
+               minify: false,
+               asset_url_prefix: "https://cdn.example/assets"
+             )
+
+    code = Enum.find(plan.artifacts, &(&1.file == "style.css")).content
+
+    for source <- ["a/logo.svg", "b/logo.svg", "a/font.woff2"] do
+      file = Map.fetch!(result.manifest, source).file
+      assert code =~ "https://cdn.example/assets/#{file}"
+      assert Enum.any?(plan.artifacts, &(&1.file == file))
+    end
+
+    refute result.manifest["a/logo.svg"].file == result.manifest["b/logo.svg"].file
+    assert code =~ "?v=1#mark"
+  end
+
+  test "compiler sources and exclusions control production scanning", %{tmp_dir: root} do
+    File.mkdir_p!(Path.join(root, "pages"))
+    File.write!(Path.join(root, "pages/index.html"), ~s(<div class="flex"></div>))
+    File.write!(Path.join(root, "pages/private.html"), ~s(<div class="hidden"></div>))
+    File.write!(Path.join(root, "outside.html"), ~s(<div class="grid"></div>))
+    css = Path.join(root, "style.css")
+
+    File.write!(
+      css,
+      "@import 'tailwindcss' source(none); @source './pages/*.html'; @source not './pages/private.html';"
+    )
+
+    config = Volt.Config.Tailwind.new(css: css)
+    opts = [outdir: Path.join(root, "output"), root: root, hash: false, minify: false]
+    assert {:ok, _, plan} = Volt.Tailwind.Build.prepare(config, opts)
+    code = Enum.find(plan.artifacts, &(&1.file == "style.css")).content
+    assert code =~ ".flex"
+    refute code =~ ".hidden"
+    refute code =~ ".grid"
+
+    File.write!(css, "@import 'tailwindcss';")
+    assert {:ok, _, automatic} = Volt.Tailwind.Build.prepare(config, opts)
+    code = Enum.find(automatic.artifacts, &(&1.file == "style.css")).content
+    assert code =~ ".grid"
+  end
+
+  test "production preparations scan fresh without registering workers", %{tmp_dir: root} do
+    css = Path.join(root, "style.css")
+    page = Path.join(root, "page.html")
+    File.write!(css, "@import 'tailwindcss' source(none);")
+    File.write!(page, ~s(<div class="hidden flex"></div>))
+    config = Volt.Config.Tailwind.new(css: css, sources: [%{base: root, pattern: "*.html"}])
+    opts = [outdir: Path.join(root, "output"), hash: false, minify: false]
+    workers = Registry.count(Volt.Tailwind.Registry)
+
+    assert {:ok, _, first} = Volt.Tailwind.Build.prepare(config, opts)
+    assert Enum.any?(first.artifacts, &String.contains?(&1.content, ".hidden"))
+    File.write!(page, ~s(<div class="flex"></div>))
+    assert {:ok, _, second} = Volt.Tailwind.Build.prepare(config, opts)
+    refute Enum.any?(second.artifacts, &String.contains?(&1.content, ".hidden"))
+    assert Registry.count(Volt.Tailwind.Registry) == workers
+  end
+
+  test "prepares CSS and referenced assets without creating output", %{tmp_dir: root} do
+    css = Path.join(root, "style.css")
+
+    File.write!(
+      css,
+      "@import 'tailwindcss' source(none); .logo { background: url('./logo.svg') }"
+    )
+
+    File.write!(Path.join(root, "logo.svg"), "<svg/>")
+    output = Path.join(root, "output")
+    config = Volt.Config.Tailwind.new(css: css, name: "site")
+
+    assert {:ok, result, plan} =
+             Volt.Tailwind.Build.prepare(config,
+               key: {:preparation_test, root},
+               outdir: output,
+               root: root,
+               hash: false,
+               minify: false,
+               asset_url_prefix: "/static"
+             )
+
+    assert result.manifest["site.css"].file == "site.css"
+    assert Enum.any?(plan.artifacts, &(&1.file == "site.css"))
+    assert Enum.any?(plan.artifacts, &(&1.content == "<svg/>"))
+    refute File.exists?(output)
+  end
+end
diff --git a/test/volt/tailwind/runtime_test.exs b/test/volt/tailwind/runtime_test.exs
new file mode 100644
index 0000000..b673367
--- /dev/null
+++ b/test/volt/tailwind/runtime_test.exs
@@ -0,0 +1,168 @@
+defmodule Volt.Tailwind.RuntimeTest do
+  use ExUnit.Case, async: false
+
+  @tag :tmp_dir
+  test "reports imported stylesheet and transitive plugin dependencies", %{tmp_dir: root} do
+    File.write!(Path.join(root, "theme.css"), "@source './pages/*.html';")
+    File.write!(Path.join(root, "helper.cjs"), "module.exports = {color: 'red'}")
+
+    File.write!(
+      Path.join(root, "plugin.cjs"),
+      "const value = require('./helper.cjs'); module.exports = ({addUtilities}) => addUtilities({'.custom': value})"
+    )
+
+    session = make_ref()
+    runtime = Volt.Tailwind.Supervisor.runtime({:session, session, :css})
+    on_exit(fn -> Volt.Tailwind.Supervisor.release_runtime(session) end)
+
+    assert {:ok, metadata} =
+             Volt.Tailwind.Runtime.compile_metadata(
+               "@import './theme.css'; @plugin './plugin.cjs'; @tailwind utilities source(none);",
+               ["custom"],
+               root,
+               runtime
+             )
+
+    assert metadata.root == :none
+    assert [%Oxide.Source{pattern: "./pages/*.html"}] = metadata.sources
+
+    for file <- ["theme.css", "plugin.cjs", "helper.cjs"] do
+      assert Path.join(root, file) in metadata.dependencies
+    end
+
+    assert metadata.code =~ ".custom"
+  end
+
+  for operation <- [:call, :compile_metadata] do
+    @tag operation: operation
+    test "compiler death during #{operation} returns an error and permits recovery", %{
+      operation: operation
+    } do
+      session = make_ref()
+      wrapper = Volt.Tailwind.Supervisor.runtime({:session, session, :css})
+      on_exit(fn -> Volt.Tailwind.Supervisor.release_runtime(session) end)
+      parent = self()
+
+      {:ok, compiler} =
+        QuickBEAM.start(
+          handlers: %{
+            "blocked" => fn [] ->
+              send(parent, {:compiler_blocked, self()})
+
+              receive do
+                :release -> :ok
+              end
+            end
+          }
+        )
+
+      # Install a controlled runtime in the wrapper to exercise the real call/exit path.
+      :sys.replace_state(wrapper, fn _ -> %Volt.JS.Runtime{pid: compiler} end)
+      Process.unlink(compiler)
+      on_exit(fn -> if Process.alive?(compiler), do: QuickBEAM.stop(compiler) end)
+
+      {:ok, _} =
+        QuickBEAM.eval(compiler, "globalThis.compileTailwindCss = () => Beam.call('blocked')")
+
+      task =
+        Task.async(fn ->
+          apply(Volt.Tailwind.Runtime, operation, ["", [], File.cwd!(), wrapper])
+        end)
+
+      assert_receive {:compiler_blocked, handler}
+      Process.exit(compiler, :kill)
+      send(handler, :release)
+      assert {:error, {:compiler_exit, _}} = Task.await(task)
+      assert Process.alive?(wrapper)
+
+      assert {:ok, css} =
+               Volt.Tailwind.Runtime.call("@tailwind utilities;", ["flex"], File.cwd!(), wrapper)
+
+      assert css =~ ".flex"
+    end
+  end
+
+  test "retained contexts reuse the compiler and reject a different runtime generation" do
+    session = make_ref()
+    runtime = Volt.Tailwind.Supervisor.runtime({:session, session, :css})
+    on_exit(fn -> Volt.Tailwind.Supervisor.release_runtime(session) end)
+
+    assert {:ok, context, metadata} =
+             Volt.Tailwind.Runtime.prepare_context("@tailwind utilities;", File.cwd!(), runtime)
+
+    assert metadata.code == ""
+    assert {:ok, first} = Volt.Tailwind.Runtime.build_context(context, ["flex"], runtime)
+    assert first =~ ".flex"
+    assert {:ok, second} = Volt.Tailwind.Runtime.build_context(context, ["grid"], runtime)
+    assert second =~ ".flex"
+    assert second =~ ".grid"
+    monitor = Process.monitor(context.runtime)
+    Process.exit(context.runtime, :kill)
+    assert_receive {:DOWN, ^monitor, :process, _, :killed}
+
+    assert {:error, :stale_compiler_context} =
+             Volt.Tailwind.Runtime.build_context(context, ["hidden"], runtime)
+
+    assert {:ok, replacement, _} =
+             Volt.Tailwind.Runtime.prepare_context("@tailwind utilities;", File.cwd!(), runtime)
+
+    refute replacement.runtime == context.runtime
+    assert {:ok, fresh} = Volt.Tailwind.Runtime.build_context(replacement, ["hidden"], runtime)
+    assert fresh =~ ".hidden"
+    refute fresh =~ ".flex"
+    assert :ok = Volt.Tailwind.Runtime.release_context(replacement, runtime)
+    assert {:error, _} = Volt.Tailwind.Runtime.build_context(replacement, [], runtime)
+  end
+
+  test "session runtimes isolate compiler death and recover on the next call" do
+    first = make_ref()
+    second = make_ref()
+    a = Volt.Tailwind.Supervisor.runtime({:session, first, :css})
+    b = Volt.Tailwind.Supervisor.runtime({:session, second, :css})
+
+    on_exit(fn ->
+      Volt.Tailwind.Supervisor.release_runtime(first)
+      Volt.Tailwind.Supervisor.release_runtime(second)
+    end)
+
+    refute a == b
+    assert {:ok, _} = Volt.Tailwind.Runtime.call("@tailwind utilities;", ["flex"], File.cwd!(), a)
+    assert {:ok, _} = Volt.Tailwind.Runtime.call("@tailwind utilities;", ["grid"], File.cwd!(), b)
+    compiler = :sys.get_state(a).pid
+    monitor = Process.monitor(compiler)
+    Process.exit(compiler, :kill)
+    assert_receive {:DOWN, ^monitor, :process, ^compiler, :killed}
+
+    assert {:ok, css} =
+             Volt.Tailwind.Runtime.call("@tailwind utilities;", ["hidden"], File.cwd!(), a)
+
+    assert css =~ ".hidden"
+    assert Process.alive?(b)
+    refute :sys.get_state(a).pid == compiler
+    assert :ok = Volt.Tailwind.Supervisor.release_runtime(first)
+    refute Process.alive?(a)
+    assert Process.alive?(b)
+  end
+
+  test "one-shot compilation releases its linked runtime on success and compiler error" do
+    {:links, before_links} = Process.info(self(), :links)
+    before_links = MapSet.new(before_links)
+
+    assert {:ok, css} =
+             Volt.Tailwind.Runtime.compile_once("@tailwind utilities;", ["flex"], File.cwd!())
+
+    assert css =~ ".flex"
+    {:links, after_success} = Process.info(self(), :links)
+    assert MapSet.new(after_success) == before_links
+
+    assert {:error, _} =
+             Volt.Tailwind.Runtime.compile_once(
+               "@import './does-not-exist.css';",
+               [],
+               File.cwd!()
+             )
+
+    {:links, after_failure} = Process.info(self(), :links)
+    assert MapSet.new(after_failure) == before_links
+  end
+end
diff --git a/test/volt/tailwind/worker_test.exs b/test/volt/tailwind/worker_test.exs
new file mode 100644
index 0000000..7d0839e
--- /dev/null
+++ b/test/volt/tailwind/worker_test.exs
@@ -0,0 +1,140 @@
+defmodule Volt.Tailwind.WorkerTest do
+  use ExUnit.Case, async: false
+
+  @moduletag :tmp_dir
+
+  test "changed source directives reconstruct scanning without retaining old discovered roots", %{
+    tmp_dir: tmp
+  } do
+    key = {:test, make_ref()}
+    on_exit(fn -> Volt.Tailwind.Supervisor.release(key) end)
+    File.mkdir_p!(Path.join(tmp, "first"))
+    File.mkdir_p!(Path.join(tmp, "second"))
+    File.write!(Path.join(tmp, "first/page.html"), "<div class='flex'></div>")
+    File.write!(Path.join(tmp, "second/page.html"), "<div class='grid'></div>")
+    first_css = "@tailwind utilities source(none); @source './first/*.html';"
+    second_css = "@tailwind utilities source(none); @source './second/*.html';"
+
+    assert {:ok, first} =
+             Volt.Tailwind.build(key: key, css: first_css, css_base: tmp, sources: [])
+
+    assert first =~ ".flex"
+    assert {:ok, second} = Volt.Tailwind.rebuild([], key: key, css: second_css)
+    assert second =~ ".grid"
+    refute second =~ ".flex"
+    assert {:ok, rebuilt} = Volt.Tailwind.build(key: key, css: second_css, css_base: tmp)
+    refute rebuilt =~ ".flex"
+  end
+
+  test "recovers a dead context without new candidates and releases it on shutdown", %{
+    tmp_dir: tmp
+  } do
+    key = {:test, make_ref()}
+    on_exit(fn -> Volt.Tailwind.Supervisor.release(key) end)
+    File.write!(Path.join(tmp, "page.html"), "<div class='flex'></div>")
+
+    assert {:ok, first} =
+             Volt.Tailwind.build(
+               key: key,
+               css: "@tailwind utilities;",
+               sources: [%{base: tmp, pattern: "*.html"}]
+             )
+
+    [{worker, _}] = Registry.lookup(Volt.Tailwind.Registry, key)
+    old = :sys.get_state(worker).context
+    monitor = Process.monitor(old.runtime)
+    Process.exit(old.runtime, :kill)
+    assert_receive {:DOWN, ^monitor, :process, _, :killed}
+    assert :unchanged = Volt.Tailwind.rebuild([], key: key)
+    state = :sys.get_state(worker)
+    refute state.context.runtime == old.runtime
+    assert {:ok, ^first} = Volt.Tailwind.Worker.stylesheet(worker)
+    assert :ok = Volt.Tailwind.Supervisor.release(key)
+    assert {:error, _} = Volt.Tailwind.Runtime.build_context(state.context, [], state.runtime)
+    assert GenServer.whereis(state.runtime)
+  end
+
+  test "candidate-only rebuild retains custom CSS and base directory", %{tmp_dir: tmp} do
+    key = {:test, make_ref()}
+    on_exit(fn -> Volt.Tailwind.Supervisor.release(key) end)
+    File.write!(Path.join(tmp, "theme.css"), ".retained { color: red }")
+    File.write!(Path.join(tmp, "page.html"), ~s(<p class="flex"></p>))
+
+    assert {:ok, first} =
+             Volt.Tailwind.build(
+               key: key,
+               css: "@import './theme.css'; @tailwind utilities;",
+               css_base: tmp,
+               minify: true,
+               sources: [%{base: tmp, pattern: "*.html"}]
+             )
+
+    assert first =~ ".retained"
+    File.write!(Path.join(tmp, "page.html"), ~s(<p class="flex grid"></p>))
+    assert {:ok, rebuilt} = Volt.Tailwind.rebuild([Path.join(tmp, "page.html")], key: key)
+    assert rebuilt =~ ".retained"
+    assert rebuilt =~ ".grid"
+    assert [{pid, _}] = Registry.lookup(Volt.Tailwind.Registry, key)
+    assert :sys.get_state(pid).compilation.minify
+  end
+
+  test "isolates scanner state by build context", %{tmp_dir: tmp} do
+    first = Path.join(tmp, "first")
+    second = Path.join(tmp, "second")
+    File.mkdir_p!(first)
+    File.mkdir_p!(second)
+    File.write!(Path.join(first, "page.html"), ~S|<p class="grid"></p>|)
+    File.write!(Path.join(second, "page.html"), ~S|<p class="flex"></p>|)
+
+    assert {:ok, first_css} =
+             Volt.Tailwind.build(
+               key: {:test, make_ref()},
+               sources: [%{base: first, pattern: "**/*.html"}]
+             )
+
+    assert {:ok, second_css} =
+             Volt.Tailwind.build(
+               key: {:test, make_ref()},
+               sources: [%{base: second, pattern: "**/*.html"}]
+             )
+
+    assert first_css =~ ".grid"
+    refute first_css =~ ".flex"
+    assert second_css =~ ".flex"
+    refute second_css =~ ".grid"
+  end
+
+  test "root workers share one compiler runtime" do
+    first_key = {:test, make_ref()}
+    second_key = {:test, make_ref()}
+
+    assert {:ok, _css} = Volt.Tailwind.build(key: first_key, sources: [])
+    runtime_pid = Process.whereis(Volt.Tailwind.Runtime)
+    assert is_pid(runtime_pid)
+
+    assert {:ok, _css} = Volt.Tailwind.build(key: second_key, sources: [])
+    assert Process.whereis(Volt.Tailwind.Runtime) == runtime_pid
+    assert Process.alive?(runtime_pid)
+
+    assert [{first_worker, _}] = Registry.lookup(Volt.Tailwind.Registry, first_key)
+    assert [{second_worker, _}] = Registry.lookup(Volt.Tailwind.Registry, second_key)
+    assert first_worker != second_worker
+  end
+
+  test "rebuild returns unchanged when generated CSS is identical", %{tmp_dir: tmp} do
+    key = {:test, make_ref()}
+    File.write!(Path.join(tmp, "page.html"), ~S|<p class="grid"></p>|)
+
+    assert {:ok, _css} =
+             Volt.Tailwind.build(
+               key: key,
+               sources: [%{base: tmp, pattern: "**/*.html"}]
+             )
+
+    assert :unchanged =
+             Volt.Tailwind.rebuild(
+               [%{content: ~S|<p class="grid"></p>|, extension: "html"}],
+               key: key
+             )
+  end
+end
diff --git a/test/volt/test/browser_runner_test.exs b/test/volt/test/browser_runner_test.exs
index 069e8d0..f9dcc0c 100644
--- a/test/volt/test/browser_runner_test.exs
+++ b/test/volt/test/browser_runner_test.exs
@@ -39,6 +39,104 @@ defmodule Volt.Test.BrowserRunnerTest do
     assert :ok = apply(module, name, [%{}])
   end
 
+  test "starts Volt's application for a project that does not", %{tmp_dir: tmp_dir} do
+    file =
+      write!(tmp_dir, "stopped.browser.test.ts", ~TS"""
+      import { test, expect } from 'volt:test'
+
+      test('runs', () => {
+        expect(document.body).toBeTruthy()
+      })
+      """)
+
+    config = Volt.Test.Config.read(browser: true, root: tmp_dir)
+    :ok = Application.stop(:volt)
+    on_exit(fn -> Application.ensure_all_started(:volt) end)
+
+    assert {:ok, %Result{status: :passed}} =
+             Volt.Test.BrowserRunner.run_test(file, 1, config: config)
+  end
+
+  test "browser test modules run concurrently", %{tmp_dir: tmp_dir} do
+    write!(tmp_dir, "async.browser.test.ts", ~TS"""
+    import { test, expect } from 'volt:test'
+
+    test('is registered', () => {
+      expect(1).toBe(1)
+    })
+    """)
+
+    assert [module] =
+             Volt.Test.ExUnit.install(
+               root: tmp_dir,
+               include: ["async.browser.test.ts"],
+               browser: true
+             )
+
+    assert %{async?: true} = module.__ex_unit__(:config)
+  end
+
+  test "tests share the run's browser and get a context each", %{tmp_dir: tmp_dir} do
+    file =
+      write!(tmp_dir, "shared.browser.test.ts", ~TS"""
+      import { test, expect } from 'volt:test'
+
+      test('starts from an empty page', () => {
+        expect(localStorage.getItem('seen')).toBeNull()
+        localStorage.setItem('seen', 'yes')
+        expect(document.body.dataset.volt).toBeUndefined()
+        document.body.dataset.volt = 'seen'
+      })
+      """)
+
+    config =
+      Volt.Test.Config.read(browser: true, include: ["shared.browser.test.ts"], root: tmp_dir)
+
+    assert {:ok, %Result{status: :passed}} =
+             Volt.Test.BrowserRunner.run_test(file, 1, config: config)
+
+    {:ok, %{guid: guid}} = Volt.Test.Browser.launch(:chromium, config.timeout)
+
+    assert {:ok, %Result{status: :passed}} =
+             Volt.Test.BrowserRunner.run_test(file, 1, config: config)
+
+    assert {:ok, %{guid: ^guid}} = Volt.Test.Browser.launch(:chromium, config.timeout)
+  end
+
+  test "bundles a file once until one of its sources changes", %{tmp_dir: tmp_dir} do
+    helper = write!(tmp_dir, "answer.ts", "export const answer = 41\n")
+
+    file =
+      write!(tmp_dir, "bundled.browser.test.ts", ~TS"""
+      import { test, expect } from 'volt:test'
+      import { answer } from './answer'
+
+      test('reads the helper', () => {
+        expect(answer).toBe(42)
+      })
+      """)
+
+    config = Volt.Test.Config.read(browser: true, root: tmp_dir)
+    bundle_opts = Volt.Test.Shared.bundle_opts(file, config, [])
+    {:ok, _pid} = Volt.Test.Browser.Supervisor.start(config)
+    {:ok, _browser} = Volt.Test.Browser.launch(:chromium, config.timeout)
+
+    assert {:ok, url} = Volt.Test.Browser.module(file, bundle_opts)
+    assert {:ok, ^url} = Volt.Test.Browser.module(file, bundle_opts)
+
+    assert {:ok, %Result{status: :failed}} =
+             Volt.Test.BrowserRunner.run_test(file, 1, config: config)
+
+    File.write!(helper, "export const answer = 42\n")
+    File.touch!(helper, System.os_time(:second) + 1)
+
+    assert {:ok, next} = Volt.Test.Browser.module(file, bundle_opts)
+    assert next != url
+
+    assert {:ok, %Result{status: :passed}} =
+             Volt.Test.BrowserRunner.run_test(file, 1, config: config)
+  end
+
   test "collects and runs tests in a browser context", %{tmp_dir: tmp_dir} do
     file =
       write!(tmp_dir, "browser.test.ts", ~TS"""
@@ -46,7 +144,9 @@ defmodule Volt.Test.BrowserRunnerTest do
 
       test('sees browser globals', () => {
         document.body.innerHTML = '<button id="ok">OK</button>'
-        expect(window.location.href).toMatch('about:blank')
+        const pageURL = new URL(window.location.href)
+        expect(pageURL.protocol).toBe('file:')
+        expect(pageURL.pathname.endsWith('/index.html')).toBe(true)
         expect(document.querySelector('#ok')?.textContent).toBe('OK')
       })
       """)
diff --git a/test/volt/test/config_test.exs b/test/volt/test/config_test.exs
index 9266d4f..828c6f4 100644
--- a/test/volt/test/config_test.exs
+++ b/test/volt/test/config_test.exs
@@ -26,6 +26,7 @@ defmodule Volt.Test.ConfigTest do
     assert config.include == ["**/*.{test,spec}.{js,ts,jsx,tsx}"]
     assert "node_modules/**" in config.exclude
     assert config.browser == false
+    assert config.granularity == :test
     assert config.browsers == [:chromium]
     assert config.timeout == 30_000
     assert config.bundle == []
@@ -36,6 +37,7 @@ defmodule Volt.Test.ConfigTest do
       root: "frontend",
       include: ["**/*.spec.ts"],
       browser: true,
+      granularity: :file,
       browsers: [:chromium, :firefox],
       timeout: 10_000,
       bundle: [plugins: [Volt.Plugin.React]]
@@ -46,6 +48,7 @@ defmodule Volt.Test.ConfigTest do
     assert config.root == "frontend"
     assert config.include == ["**/*.spec.ts"]
     assert config.browser == true
+    assert config.granularity == :file
     assert config.browsers == [:chromium, :firefox]
     assert config.timeout == 10_000
     assert config.bundle == [plugins: [Volt.Plugin.React]]
diff --git a/test/volt/test/discovery_test.exs b/test/volt/test/discovery_test.exs
index 1ac25d6..a25d2b4 100644
--- a/test/volt/test/discovery_test.exs
+++ b/test/volt/test/discovery_test.exs
@@ -22,8 +22,8 @@ defmodule Volt.Test.DiscoveryTest do
     config = %Config{root: tmp_dir, include: ["**/*.{test,spec}.{js,ts}"]}
 
     assert Volt.Test.Discovery.files(config) == [
-             Path.join([tmp_dir, "src", "a.spec.js"]),
-             Path.join([tmp_dir, "src", "b.test.ts"])
+             Path.expand(Path.join([tmp_dir, "src", "a.spec.js"])),
+             Path.expand(Path.join([tmp_dir, "src", "b.test.ts"]))
            ]
   end
 
@@ -38,7 +38,9 @@ defmodule Volt.Test.DiscoveryTest do
       exclude: ["src/generated/**", "node_modules/**"]
     }
 
-    assert Volt.Test.Discovery.files(config) == [Path.join([tmp_dir, "src", "app.test.ts"])]
+    assert Volt.Test.Discovery.files(config) == [
+             Path.expand(Path.join([tmp_dir, "src", "app.test.ts"]))
+           ]
   end
 
   test "reads config when called with profile and overrides", %{tmp_dir: tmp_dir} do
@@ -63,7 +65,7 @@ defmodule Volt.Test.DiscoveryTest do
     )
 
     assert Volt.Test.Discovery.files(:my_app_web, []) == [
-             Path.join([tmp_dir, "app", "app.test.ts"])
+             Path.expand(Path.join([tmp_dir, "app", "app.test.ts"]))
            ]
   end
 
diff --git a/test/volt/test/ex_unit_test.exs b/test/volt/test/ex_unit_test.exs
index a2f228c..3e412e5 100644
--- a/test/volt/test/ex_unit_test.exs
+++ b/test/volt/test/ex_unit_test.exs
@@ -29,21 +29,64 @@ defmodule Volt.Test.ExUnitTest do
     assert Code.ensure_loaded?(module)
 
     test_module = module.__ex_unit__()
-    tests = Enum.sort_by(test_module.tests, & &1.description)
+    tests = Enum.sort_by(test_module.tests, &test_description/1)
 
     assert length(tests) == 2
-    assert Enum.map(tests, & &1.description) == ["test math › adds", "test math › multiplies"]
+
+    assert Enum.map(tests, &test_description/1) == [
+             "test math › adds",
+             "test math › multiplies"
+           ]
 
     for test <- tests do
-      assert test.tags.js == true
-      assert test.tags.volt_file == file
-      assert test.tags.volt_test_id in [1, 2]
-      assert test.tags.file == file
-      assert test.tags.line in [4, 5]
-      assert test.tags.test_type == :test
+      assert test_tag(test, :js) == true
+      assert test_tag(test, :volt_file) == file
+      assert test_tag(test, :volt_test_id) in [1, 2]
+      assert test_tag(test, :file) == file
+      assert test_tag(test, :line) in [4, 5]
+      assert test_tag(test, :test_type) == :test
     end
   end
 
+  test "file granularity registers and executes one ExUnit test per file", %{tmp_dir: tmp_dir} do
+    file =
+      write!(tmp_dir, "file-granularity.test.ts", ~TS"""
+      import { test, expect } from 'volt:test'
+
+      test('adds', () => expect(1 + 1).toBe(2))
+      test('multiplies', () => expect(2 * 3).toBe(6))
+      """)
+
+    assert [module] =
+             Volt.Test.ExUnit.install(
+               root: tmp_dir,
+               include: ["file-granularity.test.ts"],
+               granularity: :file
+             )
+
+    assert [test] = module.__ex_unit__().tests
+    assert test_description(test) == "test file-granularity.test.ts"
+    assert test_tag(test, :js) == true
+    assert test_tag(test, :volt_file) == file
+    assert :ok = apply(module, test_name(test), [%{}])
+  end
+
+  test "file granularity tags browser modules", %{tmp_dir: tmp_dir} do
+    file = write!(tmp_dir, "browser-file.test.ts", "test('browser', () => {})\n")
+
+    assert [module] =
+             Volt.Test.ExUnit.install(
+               root: tmp_dir,
+               include: ["browser-file.test.ts"],
+               browser: true,
+               granularity: :file
+             )
+
+    assert [test] = module.__ex_unit__().tests
+    assert test_tag(test, :browser_js) == true
+    assert test_tag(test, :volt_file) == file
+  end
+
   test "install maps JS skip todo and tags to ExUnit tags", %{tmp_dir: tmp_dir} do
     file =
       write!(tmp_dir, "modifiers.test.ts", ~TS"""
@@ -56,15 +99,15 @@ defmodule Volt.Test.ExUnitTest do
 
     assert [module] = Volt.Test.ExUnit.install(root: tmp_dir, include: ["modifiers.test.ts"])
 
-    tests = Enum.sort_by(module.__ex_unit__().tests, & &1.description)
-    skipped = Enum.find(tests, &(&1.description == "test skipped"))
-    tagged = Enum.find(tests, &(&1.description == "test tagged"))
-    todo = Enum.find(tests, &(&1.description == "test todo"))
+    tests = Enum.sort_by(module.__ex_unit__().tests, &test_description/1)
+    skipped = Enum.find(tests, &(test_description(&1) == "test skipped"))
+    tagged = Enum.find(tests, &(test_description(&1) == "test tagged"))
+    todo = Enum.find(tests, &(test_description(&1) == "test todo"))
 
-    assert skipped.tags.skip == "Skipped"
-    assert todo.tags.skip == "TODO"
-    assert tagged.tags.volt_tags == ["slow", "browser"]
-    assert tagged.tags.volt_file == file
+    assert test_tag(skipped, :skip) == "Skipped"
+    assert test_tag(todo, :skip) == "TODO"
+    assert test_tag(tagged, :volt_tags) == ["slow", "browser"]
+    assert test_tag(tagged, :volt_file) == file
   end
 
   test "generated ExUnit test functions execute a single JS test", %{tmp_dir: tmp_dir} do
@@ -76,9 +119,9 @@ defmodule Volt.Test.ExUnitTest do
       """)
 
     assert [module] = Volt.Test.ExUnit.install(root: tmp_dir, include: ["single.test.ts"])
-    [%ExUnit.Test{name: name}] = module.__ex_unit__().tests
+    [test] = module.__ex_unit__().tests
 
-    assert :ok = apply(module, name, [%{}])
+    assert :ok = apply(module, test_name(test), [%{}])
     assert file
   end
 
@@ -90,8 +133,34 @@ defmodule Volt.Test.ExUnitTest do
     end
   end
 
+  test "file granularity fails when a discovered JS test file defines no tests", %{
+    tmp_dir: tmp_dir
+  } do
+    write!(tmp_dir, "empty-file.test.ts", "import { test } from 'volt:test'\n")
+
+    assert [module] =
+             Volt.Test.ExUnit.install(
+               root: tmp_dir,
+               include: ["empty-file.test.ts"],
+               granularity: :file
+             )
+
+    [test] = module.__ex_unit__().tests
+
+    assert_raise ExUnit.AssertionError, ~r/did not define any tests/, fn ->
+      apply(module, test_name(test), [%{}])
+    end
+  end
+
+  defp test_description(%ExUnit.Test{name: name}), do: Atom.to_string(name)
+  defp test_description(test), do: Map.fetch!(test, :description)
+  defp test_name(test), do: Map.fetch!(test, :name)
+
+  defp test_tag(%{tags: tags}, key), do: Map.fetch!(tags, key)
+  defp test_tag(test, key), do: Map.fetch!(test, key)
+
   defp write!(root, path, contents) do
-    path = Path.join(root, path)
+    path = Path.expand(path, root)
     File.mkdir_p!(Path.dirname(path))
     File.write!(path, contents)
     path
diff --git a/test/volt/test/lines_test.exs b/test/volt/test/lines_test.exs
index b09fe70..2247d57 100644
--- a/test/volt/test/lines_test.exs
+++ b/test/volt/test/lines_test.exs
@@ -18,6 +18,37 @@ defmodule Volt.Test.LinesTest do
     assert Volt.Test.Lines.test_lines(source, "math.test.ts") == {:ok, [4, 6, 7]}
   end
 
+  test "repeats lines for each-table cases in registration order" do
+    source = ~TS"""
+    import { describe, test } from 'volt:test'
+
+    test.each([
+      [1, 2],
+      [2, 3],
+      [3, 4]
+    ])('adds %d', () => {})
+
+    describe.each(['a', 'b'])('suite %s', () => {
+      test('first', () => {})
+      test('second', () => {})
+    })
+
+    test('after', () => {})
+    """
+
+    assert Volt.Test.Lines.test_lines(source, "each.test.ts") ==
+             {:ok, [3, 3, 3, 10, 11, 10, 11, 14]}
+  end
+
+  test "reports each-tables whose cases are not an array literal" do
+    source = ~TS"""
+    const cases = [1, 2]
+    test.each(cases)('case %d', () => {})
+    """
+
+    assert Volt.Test.Lines.test_lines(source, "dynamic.test.ts") == {:error, :dynamic_cases}
+  end
+
   test "ignores non-test calls" do
     source = ~TS"""
     const helper = { test() {} }
diff --git a/test/volt/test/runner_test.exs b/test/volt/test/runner_test.exs
index 9d27c82..2e7b5ec 100644
--- a/test/volt/test/runner_test.exs
+++ b/test/volt/test/runner_test.exs
@@ -36,6 +36,50 @@ defmodule Volt.Test.RunnerTest do
             ]} = Runner.collect_file(path)
   end
 
+  test "collects every each-table case and the tests after it", %{tmp_dir: tmp_dir} do
+    path =
+      write!(tmp_dir, "each.test.ts", ~TS"""
+      import { test } from 'volt:test'
+
+      test.each([
+        [1],
+        [2],
+        [3]
+      ])('case %d', () => {})
+
+      test('after', () => {})
+      """)
+
+    assert {:ok, tests} = Runner.collect_file(path)
+
+    assert Enum.map(tests, &{&1.full_name, &1.line}) == [
+             {"case 1", 3},
+             {"case 2", 3},
+             {"case 3", 3},
+             {"after", 9}
+           ]
+  end
+
+  test "keeps tests registered in ways the source does not show", %{tmp_dir: tmp_dir} do
+    path =
+      write!(tmp_dir, "dynamic.test.ts", ~TS"""
+      import { test } from 'volt:test'
+
+      const cases = [1, 2]
+      test.each(cases)('case %d', () => {})
+
+      for (const name of ['x', 'y']) {
+        test('loop ' + name, () => {})
+      }
+
+      test('after', () => {})
+      """)
+
+    assert {:ok, tests} = Runner.collect_file(path)
+
+    assert Enum.map(tests, & &1.full_name) == ["case 1", "case 2", "loop x", "loop y", "after"]
+  end
+
   test "collects skip todo and tag metadata", %{tmp_dir: tmp_dir} do
     path =
       write!(tmp_dir, "modifiers.test.ts", ~TS"""
@@ -92,6 +136,21 @@ defmodule Volt.Test.RunnerTest do
     assert test.status == :passed
   end
 
+  test "keeps durations monotonic when a test replaces Date.now", %{tmp_dir: tmp_dir} do
+    path =
+      write!(tmp_dir, "fake_clock.test.js", ~JS"""
+      test('replaces the wall clock', () => {
+        Date.now = () => 0
+      })
+      """)
+
+    assert {:ok, %Result{duration: duration, tests: [%Result.Test{duration: test_duration}]}} =
+             Runner.run_file(path)
+
+    assert duration >= 0
+    assert test_duration >= 0
+  end
+
   test "loads setup files before the test module", %{tmp_dir: tmp_dir} do
     setup_path =
       write!(tmp_dir, "setup.ts", ~TS"""
@@ -186,7 +245,7 @@ defmodule Volt.Test.RunnerTest do
   end
 
   defp write!(root, path, contents) do
-    path = Path.join(root, path)
+    path = Path.expand(path, root)
     File.mkdir_p!(Path.dirname(path))
     File.write!(path, contents)
     path
diff --git a/test/volt/watcher/path_test.exs b/test/volt/watcher/path_test.exs
new file mode 100644
index 0000000..958bbf4
--- /dev/null
+++ b/test/volt/watcher/path_test.exs
@@ -0,0 +1,29 @@
+defmodule Volt.Watcher.PathTest do
+  use ExUnit.Case, async: true
+
+  @tag :tmp_dir
+  test "normalizes filesystem aliases to a configured root", %{tmp_dir: tmp_dir} do
+    root = Path.join(tmp_dir, "root")
+    alias_path = Path.join(tmp_dir, "alias")
+    File.mkdir_p!(root)
+    File.ln_s!(root, alias_path)
+
+    assert Volt.Watcher.Path.normalize_from_roots(Path.join(alias_path, "app.js"), [root]) ==
+             Path.join(root, "app.js")
+  end
+
+  @tag :tmp_dir
+  test "normalizes an aliased event for the watched root itself", %{tmp_dir: tmp_dir} do
+    root = Path.join(tmp_dir, "root")
+    alias_path = Path.join(tmp_dir, "alias")
+    File.mkdir_p!(root)
+    File.ln_s!(root, alias_path)
+
+    assert Volt.Watcher.Path.normalize_from_roots(alias_path, [root]) == root
+  end
+
+  test "preserves paths that do not belong to a configured root" do
+    assert Volt.Watcher.Path.normalize_from_roots("/outside/app.js", ["/site/assets"]) ==
+             "/outside/app.js"
+  end
+end
diff --git a/test/volt/watcher_test.exs b/test/volt/watcher_test.exs
index a522313..01c05ef 100644
--- a/test/volt/watcher_test.exs
+++ b/test/volt/watcher_test.exs
@@ -2,7 +2,9 @@ defmodule Volt.WatcherTest do
   use ExUnit.Case, async: false
 
   setup %{test: test_name} do
-    watch_dir = Path.join([System.tmp_dir!(), "volt-watcher-test", to_string(test_name)])
+    watch_dir =
+      Path.expand(Path.join("volt-watcher-test", to_string(test_name)), System.tmp_dir!())
+
     File.mkdir_p!(watch_dir)
     Volt.HMR.ImportGraph.clear()
     Volt.Cache.clear()
@@ -10,6 +12,330 @@ defmodule Volt.WatcherTest do
     {:ok, watch_dir: watch_dir}
   end
 
+  @tag :tmp_dir
+  test "installing a missing package repairs session compilation", %{tmp_dir: root} do
+    assets = Path.join(root, "assets")
+    modules = Path.join(root, "node_modules")
+    File.mkdir_p!(assets)
+    File.mkdir_p!(modules)
+    css = Path.join(assets, "app.css")
+    File.write!(css, "@plugin 'missing-recovery-fixture';")
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: make_ref(),
+         watcher: [
+           root: assets,
+           name: nil,
+           tailwind: true,
+           tailwind_css: css,
+           tailwind_sources: []
+         ]}
+      )
+
+    {_, watcher, _, _} =
+      Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+        id == Volt.Dev.Session.Watcher
+      end)
+
+    state = :sys.get_state(watcher)
+    package = Path.join(modules, "missing-recovery-fixture")
+    metadata = Path.join(package, "package.json")
+    assert metadata in state.config.tailwind_dependencies
+    File.mkdir_p!(package)
+    File.write!(metadata, ~s({"name":"missing-recovery-fixture","main":"index.js"}))
+
+    File.write!(
+      Path.join(package, "index.js"),
+      "module.exports = ({addBase}) => addBase({'.installed': {color: 'red'}})"
+    )
+
+    assert {:noreply, queued} =
+             Volt.Watcher.handle_info({:file_event, self(), {metadata, [:created]}}, state)
+
+    assert is_reference(queued.tailwind_timer)
+    Process.cancel_timer(queued.tailwind_timer)
+    assert {:noreply, _} = Volt.Watcher.handle_info(:tailwind_rebuild, queued)
+    assert {:ok, code} = Volt.Tailwind.Worker.stylesheet(state.tables.stylesheet_worker)
+    assert code =~ ".installed"
+  end
+
+  @tag :tmp_dir
+  test "missing plugin helper creation repairs session compilation", %{tmp_dir: root} do
+    assets = Path.join(root, "assets")
+    external = Path.join(root, "plugins")
+    File.mkdir_p!(assets)
+    File.mkdir_p!(external)
+    plugin = Path.join(external, "theme.cjs")
+    helper = Path.join(external, "helper.cjs")
+
+    File.write!(
+      plugin,
+      "const values = require('./helper.cjs'); module.exports = ({addBase}) => addBase(values)"
+    )
+
+    css = Path.join(assets, "app.css")
+    File.write!(css, "@plugin '../plugins/theme.cjs';")
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: make_ref(),
+         watcher: [
+           root: assets,
+           name: nil,
+           tailwind: true,
+           tailwind_css: css,
+           tailwind_sources: []
+         ]}
+      )
+
+    {_, watcher, _, _} =
+      Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+        id == Volt.Dev.Session.Watcher
+      end)
+
+    state = :sys.get_state(watcher)
+    assert helper in state.config.tailwind_dependencies
+    assert external in state.tailwind_dirs
+    File.write!(helper, "module.exports = {'.repaired': {color: 'red'}}")
+
+    assert {:noreply, queued} =
+             Volt.Watcher.handle_info({:file_event, self(), {helper, [:created]}}, state)
+
+    Process.cancel_timer(queued.tailwind_timer)
+    assert queued.tailwind_full?
+    assert {:noreply, _} = Volt.Watcher.handle_info(:tailwind_rebuild, queued)
+    assert {:ok, code} = Volt.Tailwind.Worker.stylesheet(state.tables.stylesheet_worker)
+    assert code =~ ".repaired"
+  end
+
+  @tag :tmp_dir
+  test "missing external CSS creation repairs failed initial compilation", %{tmp_dir: root} do
+    assets = Path.join(root, "assets")
+    File.mkdir_p!(assets)
+    css = Path.join(assets, "app.css")
+    missing = Path.join(root, "external/theme.css")
+    File.write!(css, "@import '../external/theme.css';")
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: make_ref(),
+         watcher: [
+           root: assets,
+           name: nil,
+           tailwind: true,
+           tailwind_css: css,
+           tailwind_sources: []
+         ]}
+      )
+
+    {_, watcher, _, _} =
+      Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+        id == Volt.Dev.Session.Watcher
+      end)
+
+    state = :sys.get_state(watcher)
+    assert missing in state.config.tailwind_dependencies
+    assert root in state.tailwind_dirs
+    File.mkdir_p!(Path.dirname(missing))
+    File.write!(missing, ".repaired { color: red }")
+
+    assert {:noreply, queued} =
+             Volt.Watcher.handle_info({:file_event, self(), {missing, [:created]}}, state)
+
+    Process.cancel_timer(queued.tailwind_timer)
+    assert queued.tailwind_full?
+    assert {:noreply, _} = Volt.Watcher.handle_info(:tailwind_rebuild, queued)
+    assert {:ok, code} = Volt.Tailwind.Worker.stylesheet(state.tables.stylesheet_worker)
+    assert code =~ ".repaired"
+  end
+
+  @tag :tmp_dir
+  test "session observes compiler-discovered external stylesheet dependencies", %{tmp_dir: root} do
+    assets = Path.join(root, "assets")
+    external = Path.join(root, "external")
+    File.mkdir_p!(assets)
+    File.mkdir_p!(external)
+    imported = Path.join(external, "theme.css")
+    File.write!(imported, ".external { color: red }")
+    css = Path.join(assets, "app.css")
+
+    File.write!(
+      css,
+      "@import '../external/theme.css'; @source '../external/*.html'; @tailwind utilities source(none);"
+    )
+
+    supervisor =
+      start_supervised!(
+        {Volt.Dev.Session.Supervisor,
+         identity: make_ref(),
+         watcher: [
+           root: assets,
+           name: nil,
+           tailwind: true,
+           tailwind_css: css,
+           tailwind_sources: []
+         ]}
+      )
+
+    {_, watcher, _, _} =
+      Enum.find(Supervisor.which_children(supervisor), fn {id, _, _, _} ->
+        id == Volt.Dev.Session.Watcher
+      end)
+
+    state = :sys.get_state(watcher)
+    assert imported in state.config.tailwind_dependencies
+    assert external in state.tailwind_dirs
+    File.write!(imported, ".external { color: blue }")
+
+    assert {:noreply, queued} =
+             Volt.Watcher.handle_info({:file_event, self(), {imported, [:modified]}}, state)
+
+    assert queued.tailwind_full?
+    Process.cancel_timer(queued.tailwind_timer)
+    assert {:noreply, rebuilt} = Volt.Watcher.handle_info(:tailwind_rebuild, queued)
+    assert {:ok, updated} = Volt.Tailwind.Worker.stylesheet(state.tables.stylesheet_worker)
+    assert updated =~ "blue"
+    external_watcher = Map.fetch!(rebuilt.discovered_watches, external)
+    File.write!(css, "@tailwind utilities source(none);")
+
+    assert {:noreply, pruned} =
+             Volt.Watcher.handle_info(:tailwind_rebuild, %{rebuilt | tailwind_full?: true})
+
+    refute external in pruned.tailwind_dirs
+    refute imported in pruned.config.tailwind_dependencies
+    refute Process.alive?(external_watcher)
+    assert assets in pruned.tailwind_dirs
+  end
+
+  @tag :tmp_dir
+  test "a change in a linked package forgets the pre-bundle and reloads the page", %{
+    tmp_dir: root
+  } do
+    assets = Path.join(root, "assets")
+    linked = Path.join(root, "packages/client")
+    File.mkdir_p!(assets)
+    File.mkdir_p!(linked)
+    File.mkdir_p!(Path.join(root, "node_modules"))
+    File.ln_s!("../packages/client", Path.join(root, "node_modules/client"))
+    File.write!(Path.join(linked, "index.js"), "export const version = 1")
+
+    watcher = start_supervised!({Volt.Watcher, root: assets, name: nil})
+    Registry.register(Volt.HMR.Registry, :clients, nil)
+    state = :sys.get_state(watcher)
+    assert state.linked_dirs == [Path.expand(linked)]
+
+    prebundle_opts = [root: assets, plugins: []]
+    Volt.Dev.Prebundled.ensure(prebundle_opts, fn -> :ok end)
+    changed = Path.join(linked, "index.js")
+
+    assert {:noreply, _state} =
+             Volt.Watcher.handle_info({:file_event, self(), {changed, [:modified]}}, state)
+
+    assert_receive {:volt_hmr, :update, %{changes: [:vendor]}}
+    assert :ets.lookup(:volt_vendor_prebundled, prebundle_opts) == []
+  end
+
+  @tag :tmp_dir
+  test "document reload waits for successful CSS and remains pending on failure", %{tmp_dir: root} do
+    File.mkdir_p!(Path.join(root, "pages"))
+    page = Path.join(root, "pages/index.astral")
+    css = Path.join(root, "app.css")
+    File.write!(page, "<div class='flex'></div>")
+    File.write!(css, "@tailwind utilities;")
+
+    watcher =
+      start_supervised!(
+        {Volt.Watcher,
+         root: root,
+         name: nil,
+         tailwind: true,
+         tailwind_css: css,
+         reload_dirs: [Path.dirname(page)],
+         tailwind_sources: [%{base: root, pattern: "pages/*.astral"}]}
+      )
+
+    Registry.register(Volt.HMR.Registry, :clients, nil)
+    state = :sys.get_state(watcher)
+
+    assert {:noreply, queued} =
+             Volt.Watcher.handle_info({:file_event, self(), {page, [:modified]}}, state)
+
+    Process.cancel_timer(queued.tailwind_timer)
+    refute_received {:volt_hmr, _, _}
+    assert queued.pending_reloads == [page]
+    # Feed state directly to avoid filesystem timing; a missing input forces the rebuild error.
+    failed = %{
+      queued
+      | tailwind_full?: true,
+        config: Map.put(queued.config, :tailwind_css, Path.join(root, "missing.css"))
+    }
+
+    assert {:noreply, pending} = Volt.Watcher.handle_info(:tailwind_rebuild, failed)
+    assert pending.pending_reloads == [page]
+    assert pending.tailwind_full?
+    assert_receive {:volt_hmr, :error, _}
+    refute_received {:volt_hmr, :update, _}
+    File.write!(css, "@tailwind utilities; .changed { color: red }")
+
+    assert {:noreply, recovered} =
+             Volt.Watcher.handle_info(
+               {:file_event, self(), {page, [:modified]}},
+               %{pending | config: state.config}
+             )
+
+    Process.cancel_timer(recovered.tailwind_timer)
+    assert recovered.tailwind_full?
+    assert {:noreply, completed} = Volt.Watcher.handle_info(:tailwind_rebuild, recovered)
+    assert completed.pending_reloads == []
+    assert_receive {:volt_hmr, :update, %{changes: [:style]}}
+    assert_receive {:volt_hmr, :update, %{changes: ["document"]}}
+    repeated = %{completed | tailwind_full?: true, pending_reloads: [page]}
+
+    assert {:noreply, %{pending_reloads: []}} =
+             Volt.Watcher.handle_info(:tailwind_rebuild, repeated)
+
+    assert_receive {:volt_hmr, :update, %{changes: ["document"]}}
+    refute_received {:volt_hmr, :update, %{changes: [:style]}}
+  end
+
+  @tag :tmp_dir
+  test "external source roots are watched and unknown source extensions schedule Tailwind", %{
+    tmp_dir: root
+  } do
+    assets = Path.join(root, "assets")
+    pages = Path.join(root, "pages")
+    File.mkdir_p!(assets)
+    File.mkdir_p!(pages)
+    source = Path.join(pages, "index.astral")
+    File.write!(source, "<div class='flex'></div>")
+    css = Path.join(assets, "app.css")
+    File.write!(css, "@tailwind utilities;")
+
+    watcher =
+      start_supervised!(
+        {Volt.Watcher,
+         root: assets,
+         name: nil,
+         tailwind: true,
+         tailwind_css: css,
+         tailwind_sources: [%{base: pages, pattern: "**/*.astral"}]}
+      )
+
+    state = :sys.get_state(watcher)
+    assert pages in state.tailwind_dirs
+
+    assert {:noreply, scheduled} =
+             Volt.Watcher.handle_info({:file_event, self(), {source, [:modified]}}, state)
+
+    assert source in scheduled.tailwind_changed
+    assert is_reference(scheduled.tailwind_timer)
+    Process.cancel_timer(scheduled.tailwind_timer)
+  end
+
   test "broadcasts via registry on dispatch" do
     Registry.register(Volt.HMR.Registry, :clients, nil)
 
@@ -59,6 +385,144 @@ defmodule Volt.WatcherTest do
     GenServer.stop(pid)
   end
 
+  test "a changed source makes the next request scan for new package imports", %{
+    watch_dir: watch_dir
+  } do
+    source = Path.join(watch_dir, "app.ts")
+    File.write!(source, "export const x = 1")
+    opts = [root: watch_dir, node_modules: Path.join(watch_dir, "node_modules")]
+
+    :ok = Volt.Dev.Prebundled.ensure(opts, fn -> :ok end)
+    assert :ets.lookup(:volt_vendor_prebundled, opts) != []
+
+    {:ok, pid} = Volt.Watcher.start_link(root: watch_dir, name: :test_watcher_forget_prebundled)
+    state = send_file_event(pid, source)
+    Process.cancel_timer(state.pending[source])
+
+    assert :ets.lookup(:volt_vendor_prebundled, opts) == []
+    GenServer.stop(pid)
+  end
+
+  test "ignores configured watcher paths", %{watch_dir: watch_dir} do
+    generated_dir = Path.join(watch_dir, ".generated")
+    entry = Path.join(generated_dir, "entry.ts")
+    File.mkdir_p!(generated_dir)
+
+    {:ok, pid} =
+      Volt.Watcher.start_link(
+        root: watch_dir,
+        watch_ignored: [Path.join(generated_dir, "**")],
+        name: :test_watcher_ignored
+      )
+
+    state = send_file_event(pid, entry)
+
+    refute Map.has_key?(state.pending, entry)
+    GenServer.stop(pid)
+  end
+
+  test "does not ignore sibling watcher paths", %{watch_dir: watch_dir} do
+    generated_dir = Path.join(watch_dir, ".generated")
+    source_file = Path.join([watch_dir, "source", "entry.ts"])
+    File.mkdir_p!(Path.dirname(source_file))
+    File.write!(source_file, "export const value = 1")
+
+    {:ok, pid} =
+      Volt.Watcher.start_link(
+        root: watch_dir,
+        watch_ignored: [Path.join(generated_dir, "**")],
+        name: :test_watcher_ignored_sibling
+      )
+
+    state = send_file_event(pid, source_file)
+
+    assert Map.has_key?(state.pending, source_file)
+    Process.cancel_timer(state.pending[source_file])
+    GenServer.stop(pid)
+  end
+
+  test "supports relative watcher ignore globs", %{watch_dir: watch_dir} do
+    entry = Path.join([watch_dir, ".generated", "entry.ts"])
+
+    {:ok, pid} =
+      Volt.Watcher.start_link(
+        root: watch_dir,
+        watch_ignored: ["**/.generated/**"],
+        name: :test_watcher_relative_ignore
+      )
+
+    state = send_file_event(pid, entry)
+
+    refute Map.has_key?(state.pending, entry)
+    GenServer.stop(pid)
+  end
+
+  test "resolves relative watcher ignore globs from the project directory", %{
+    watch_dir: watch_dir
+  } do
+    generated_dir = Path.join(File.cwd!(), "tmp/volt-watcher-generated")
+    entry = Path.join(generated_dir, "index.js")
+    File.mkdir_p!(generated_dir)
+    on_exit(fn -> File.rm_rf!(generated_dir) end)
+
+    {:ok, pid} =
+      Volt.Watcher.start_link(
+        root: watch_dir,
+        watch_dirs: [generated_dir],
+        watch_ignored: ["tmp/volt-watcher-generated/**"],
+        name: :test_watcher_project_relative_ignore
+      )
+
+    state = send_file_event(pid, entry)
+
+    refute Map.has_key?(state.pending, entry)
+    GenServer.stop(pid)
+  end
+
+  test "does not reload when a generated file is rewritten with identical content", %{
+    watch_dir: watch_dir
+  } do
+    Registry.register(Volt.HMR.Registry, :clients, nil)
+
+    generated_dir = Path.join(watch_dir, "generated")
+    root = Path.join(watch_dir, "assets")
+    index = Path.join(generated_dir, "index.js")
+    File.mkdir_p!(generated_dir)
+    File.mkdir_p!(root)
+    File.write!(index, "export const hooks = {};")
+
+    {:ok, pid} =
+      Volt.Watcher.start_link(
+        root: root,
+        watch_dirs: [generated_dir],
+        name: :test_watcher_identical_rewrite
+      )
+
+    send(pid, {:file_event, self(), {index, [:modified]}})
+    refute_receive {:volt_hmr, :update, _}, 300
+
+    File.write!(index, "export const hooks = {changed: true};")
+    send(pid, {:file_event, self(), {index, [:modified]}})
+    assert_receive {:volt_hmr, :update, %{changes: [:full]}}, 2000
+
+    send(pid, {:file_event, self(), {index, [:modified]}})
+    refute_receive {:volt_hmr, :update, _}, 300
+
+    GenServer.stop(pid)
+  end
+
+  test "ignores dependency directories by default", %{watch_dir: watch_dir} do
+    entry = Path.join([watch_dir, "node_modules", "example", "index.ts"])
+
+    {:ok, pid} =
+      Volt.Watcher.start_link(root: watch_dir, name: :test_watcher_default_ignored)
+
+    state = send_file_event(pid, entry)
+
+    refute Map.has_key?(state.pending, entry)
+    GenServer.stop(pid)
+  end
+
   test "detects asset changes and broadcasts reload update", %{watch_dir: watch_dir} do
     Registry.register(Volt.HMR.Registry, :clients, nil)
 
@@ -101,7 +565,7 @@ defmodule Volt.WatcherTest do
     GenServer.stop(pid)
   end
 
-  test "reload_dirs trigger full browser reloads for non-asset source files", %{
+  test "reload_dirs ask open pages to revalidate for non-asset source files", %{
     watch_dir: watch_dir
   } do
     Registry.register(Volt.HMR.Registry, :clients, nil)
@@ -120,10 +584,9 @@ defmodule Volt.WatcherTest do
         name: :test_watcher_reload_dirs
       )
 
-    Process.sleep(100)
-    File.write!(page, "# Updated")
+    send_file_event(pid, page)
 
-    assert_receive {:volt_hmr, :update, %{path: path, changes: ["full"]}}, 2000
+    assert_receive {:volt_hmr, :update, %{path: path, changes: ["document"]}}
     assert path == Path.relative_to_cwd(page)
 
     GenServer.stop(pid)
@@ -152,7 +615,7 @@ defmodule Volt.WatcherTest do
 
     refute_receive {:volt_hmr, :update, %{path: "app.css", changes: [:style]}}, 50
 
-    assert_receive {:volt_hmr, :update, %{path: "assets/css/app.css", changes: [:style]}},
+    assert_receive {:volt_hmr, :update, %{path: "/assets/css/app.css", changes: [:style]}},
                    3000
 
     assert File.regular?(Path.join(outdir, "app.css"))
@@ -181,7 +644,7 @@ defmodule Volt.WatcherTest do
     Process.sleep(100)
     File.write!(imported_css, ".imported-card { color: rgb(239 68 68); }")
 
-    assert_receive {:volt_hmr, :update, %{path: "assets/css/app.css", changes: [:style]}},
+    assert_receive {:volt_hmr, :update, %{path: "/assets/css/app.css", changes: [:style]}},
                    3000
 
     css = File.read!(Path.join(outdir, "app.css"))
@@ -211,7 +674,7 @@ defmodule Volt.WatcherTest do
     Process.sleep(100)
     File.write!(heex_file, ~s(<div class="flex mt-4 bg-blue-500">hi</div>))
 
-    assert_receive {:volt_hmr, :update, %{path: "assets/css/app.css", changes: [:style]}},
+    assert_receive {:volt_hmr, :update, %{path: "/assets/css/app.css", changes: [:style]}},
                    3000
 
     assert File.exists?(Path.join(outdir, "app.css"))
@@ -220,4 +683,13 @@ defmodule Volt.WatcherTest do
 
     GenServer.stop(pid)
   end
+
+  defp send_file_event(pid, path) do
+    :sys.replace_state(pid, fn state ->
+      send(pid, {:file_event, self(), {path, [:created]}})
+      state
+    end)
+
+    :sys.get_state(pid)
+  end
 end