* [PostCSS Plugin Guidelines](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#postcss-plugin-guidelines)

* [API](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#1-api)

* [1.1 Clear name with `postcss-` prefix](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#11-clear-name-with-postcss--prefix)

* [1.2. Do one thing, and do it well](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#12-do-one-thing-and-do-it-well)

* [1.3. Do not use mixins](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#13-do-not-use-mixins)

* [1.4. Keep `postcss` to `peerDependencies`](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#14-keep-postcss-to-peerdependencies)

* [1.5. Set `plugin.postcssPlugin` with plugin name](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#15-set-pluginpostcssplugin-with-plugin-name)

* [Processing](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#2-processing)

* [2.1. Plugin must be tested](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#21-plugin-must-be-tested)

* [2.2. Use asynchronous methods whenever possible](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#22-use-asynchronous-methods-whenever-possible)

* [2.3. Use fast node’s scanning](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#23-use-fast-nodes-scanning)

* [2.4. Set `node.source` for new nodes](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#24-set-nodesource-for-new-nodes)

* [2.5. Use only the public PostCSS API](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#25-use-only-the-public-postcss-api)

* [Dependencies](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#3-dependencies)

* [3.1. Use messages to specify dependencies](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#31-use-messages-to-specify-dependencies)

* [Errors](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#4-errors)

* [4.1. Use `node.error` on CSS relevant errors](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#41-use-nodeerror-on-css-relevant-errors)

* [4.2. Use `result.warn` for warnings](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#42-use-resultwarn-for-warnings)

* [Documentation](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#5-documentation)

* [5.1. Document your plugin in English](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#51-document-your-plugin-in-english)

* [5.2. Include input and output examples](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#52-include-input-and-output-examples)

* [5.3. Maintain a changelog](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#53-maintain-a-changelog)

* [5.4. Include `postcss-plugin` keyword in `package.json`](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/plugin.md#54-include-postcss-plugin-keyword-in-packagejson)

* [PostCSS Runner Guidelines](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#postcss-runner-guidelines)

* [API](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#1-api)

* [1.1. Accept functions in plugin parameters](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#11-accept-functions-in-plugin-parameters)

* [Processing](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#21-set-from-and-to-processing-options)

* [2.1. Set `from` and `to` processing options](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#21-set-from-and-to-processing-options)

* [2.2. Use only the asynchronous API](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#22-use-only-the-asynchronous-api)

* [2.3. Use only the public PostCSS API](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#23-use-only-the-public-postcss-api)

* [3.1. Rebuild when dependencies change](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#31-rebuild-when-dependencies-change)

* [Output](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#4-output)

* [4.1. Don’t show JS stack for `CssSyntaxError`](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#41-dont-show-js-stack-for-csssyntaxerror)

* [4.2. Display `result.warnings()`](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#42-display-resultwarnings)

* [4.3. Allow the user to write source maps to different files](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#43-allow-the-user-to-write-source-maps-to-different-files)

* [Documentation](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#5-documentation)

* [5.1. Document your runner in English](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#51-document-your-runner-in-english)

* [5.2. Maintain a changelog](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#52-maintain-a-changelog)

* [5.3. `postcss-runner` keyword in `package.json`](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#53-postcss-runner-keyword-in-packagejson)

* [5.4. Keep postcss to peerDependencies](https://github.com/postcss/postcss/blob/docs-index/docs/guidelines/runner.md#54-keep-postcss-to-peerdependencies)