nodejs · avivkeller · Aug 16, 2026
diff --git a/doc/api/cli.md b/doc/api/cli.md
@@ -1563,14 +1563,6 @@ changes:
 
 Enable experimental WebAssembly System Interface (WASI) support.
 
-### `--experimental-web-worker`
-
-<!-- YAML
-added: REPLACEME
--->
-
-Enable experimental support for the Web Worker API.
-
 ### `--experimental-worker-inspection`
 
 <!-- YAML
@@ -2169,6 +2161,20 @@ changes:
 
 Disable [`Web Storage`][] support.
 
+### `--no-experimental-web-worker`
+
+<!-- YAML
+added: REPLACEME
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/65323
+    description: This feature is now enabled by default.
+-->
+
+> Stability: 1.1 - Active Development
+
+Disable support for the Web Worker API.
+
 ### `--no-extra-info-on-fatal-exception`
 
 <!-- YAML
@@ -3898,7 +3904,6 @@ one is included in the list below.
 * `--experimental-vfs`
 * `--experimental-vm-modules`
 * `--experimental-wasi-unstable-preview1`
-* `--experimental-web-worker`
 * `--force-context-aware`
 * `--force-fips`
 * `--force-node-api-uncaught-exceptions-policy`
@@ -3931,6 +3936,7 @@ one is included in the list below.
 * `--no-experimental-strip-types`
 * `--no-experimental-websocket`
 * `--no-experimental-webstorage`
+* `--no-experimental-web-worker`
 * `--no-extra-info-on-fatal-exception`
 * `--no-force-async-hooks-checks`
 * `--no-global-search-paths`

diff --git a/doc/node.1 b/doc/node.1
@@ -836,9 +836,6 @@ Enable experimental ES Module support in the \fBnode:vm\fR module.
 .It Fl -experimental-wasi-unstable-preview1
 Enable experimental WebAssembly System Interface (WASI) support.
 .
-.It Fl -experimental-web-worker
-Enable experimental support for the Web Worker API.
-.
 .It Fl -experimental-worker-inspection
 Enable experimental support for the worker inspection with Chrome DevTools.
 .
@@ -1116,6 +1113,9 @@ Disable exposition of \fB<WebSocket>\fR on the global scope.
 .It Fl -no-experimental-webstorage
 Disable \fBWeb Storage\fR support.
 .
+.It Fl -no-experimental-web-worker
+Disable support for the Web Worker API.
+.
 .It Fl -no-extra-info-on-fatal-exception
 Hide extra information on fatal exception that causes exit.
 .
@@ -2027,8 +2027,6 @@ one is included in the list below.
 .It
 \fB--experimental-wasi-unstable-preview1\fR
 .It
-\fB--experimental-web-worker\fR
-.It
 \fB--force-context-aware\fR
 .It
 \fB--force-fips\fR
@@ -2093,6 +2091,8 @@ one is included in the list below.
 .It
 \fB--no-experimental-webstorage\fR
 .It
+\fB--no-experimental-web-worker\fR
+.It
 \fB--no-extra-info-on-fatal-exception\fR
 .It
 \fB--no-force-async-hooks-checks\fR

diff --git a/src/node_options.cc b/src/node_options.cc
@@ -599,7 +599,7 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
             "experimental Web Worker API",
             BOOL_FIELD(experimental_web_worker),
             kAllowedInEnvvar,
-            false);
+            true);
   AddOption("--experimental-websocket",
             "experimental WebSocket API",
             BOOL_FIELD(experimental_websocket),

diff --git a/src/node_options.h b/src/node_options.h
@@ -202,7 +202,7 @@ class EnvironmentOptions : public Options {
   DEFINE_BOOL_FIELD(experimental_addon_modules) = true;
   DEFINE_BOOL_FIELD(experimental_eventsource) = EXPERIMENTALS_DEFAULT_VALUE;
   DEFINE_BOOL_FIELD(experimental_ffi) = EXPERIMENTALS_DEFAULT_VALUE;
-  DEFINE_BOOL_FIELD(experimental_web_worker) = EXPERIMENTALS_DEFAULT_VALUE;
+  DEFINE_BOOL_FIELD(experimental_web_worker) = true;
   DEFINE_BOOL_FIELD(experimental_websocket) = true;
   DEFINE_BOOL_FIELD(experimental_sqlite) = HAVE_SQLITE;
   DEFINE_BOOL_FIELD(experimental_stream_iter) = EXPERIMENTALS_DEFAULT_VALUE;

diff --git a/test/common/wpt.js b/test/common/wpt.js
@@ -836,11 +836,7 @@ class WPTRunner {
     this.resource = new ResourceLoader(path);
     this.concurrency = concurrency;
 
-    // Since we need to prepare the Web Worker APIs
-    // in the harness that runs on all WPT workers,
-    // we enable the API globally. This has no practical
-    // effect on the non-web-worker tests, however.
-    this.flags = ['--experimental-web-worker'];
+    this.flags = [];
     this.globalThisInitScripts = [];
     this.initScript = null;
 

diff --git a/test/parallel/test-common-wpt-backends.js b/test/parallel/test-common-wpt-backends.js
@@ -16,7 +16,7 @@ const queueProbe = process.env.NODE_TEST_WPT_QUEUE_PROBE === '1';
 
 const harnessPath = fixtures.path('wpt', 'resources', 'testharness.js');
 const specPath = fixtures.path('wpt-backends-spec.js');
-const execArgv = ['--experimental-web-worker'];
+const execArgv = [];
 
 function payload(throws) {
   return {

diff --git a/test/parallel/test-common-wpt-webworker-error.js b/test/parallel/test-common-wpt-webworker-error.js
@@ -10,7 +10,7 @@ const { Worker } = require('worker_threads');
 
 const workerPath = path.join(__dirname, '../common/wpt/worker.js');
 const harnessPath = fixtures.path('wpt', 'resources', 'testharness.js');
-const execArgv = ['--experimental-web-worker'];
+const execArgv = [];
 const workerData = {
   testRelativePath: 'workers/error-after-result.any.js',
   wptRunner: path.join(__dirname, '../common/wpt.js'),

diff --git a/test/parallel/test-worker-spec-differences.js b/test/parallel/test-worker-spec-differences.js
@@ -1,4 +1,3 @@
-// Flags: --experimental-web-worker
 'use strict';
 
 const common = require('../common');