# Extension.js

> Build browser extensions for Chrome, Edge, and Firefox with one modern workflow. Extension.js handles manifest compilation, browser-specific output, reload behavior, and packaging so you can focus on product features.

- [Documentation (132 pages)](https://extension.js.org/_llms/en/documentation.md): Documentation for Documentation.

## Home

- [The cross-browser extension framework](https://extension.js.org/index.md): Build browser extensions for Chrome, Edge, and Firefox from one project with manifest compilation, fast reloads on save, and store-ready packaging.

## Templates

- [Extension project templates for React, Vue, and more](https://extension.js.org/docs/getting-started/templates.md): Scaffold browser extensions from official Extension.js templates for React, Preact, Vue, Svelte, TypeScript, WebAssembly, and vanilla JS instead of building from scratch.
- [JavaScript browser extension template](https://extension.js.org/docs/getting-started/templates/javascript.md): Scaffold a vanilla JavaScript browser extension with the Extension.js CLI, including manifest, sidebar, and content script wiring out of the box.
- [TypeScript browser extension template](https://extension.js.org/docs/getting-started/templates/typescript.md): Scaffold a TypeScript browser extension with strict typing, Manifest V3 types, and pre-wired sidebar, content, and background script entry points.
- [Svelte browser extension template](https://extension.js.org/docs/getting-started/templates/svelte.md): Scaffold a Svelte browser extension with single-file components, a compiled runtime, and ready-made sidebar and content script wiring.
- [Vue browser extension template](https://extension.js.org/docs/getting-started/templates/vue.md): Scaffold a Vue 3 browser extension with single-file components and the Composition API wired up for sidebar and content script contexts.
- [Preact browser extension template](https://extension.js.org/docs/getting-started/templates/preact.md): Scaffold a Preact browser extension with the React-compatible API in a 3kB runtime, tuned for size-sensitive popups and content scripts.
- [React browser extension template](https://extension.js.org/docs/getting-started/templates/react.md): Scaffold a React browser extension with full Manifest V3 support, JSX, and ready-to-ship sidebar and content script entry points.

## AI

### Connect AI to docs

- [AI access via MCP and llms.txt](https://extension.js.org/docs/ai-access.md): Connect Extension.js documentation to your AI tools via the hosted MCP server, or pull structured summaries from the llms.txt endpoint.

## Blog

### Posts

- [Extension.js blog and release announcements](https://extension.js.org/blog/index.md): Stay up to date with Extension.js release notes, feature announcements, and ecosystem updates for cross-browser extension development.
- [Announcing Extension.js 4.0.0](https://extension.js.org/blog/announcing-4-0-0.md): Extension.js 4.0.0 moves to Node.js 22, fixes classic multi-file content scripts in dev, speeds up Safari development, and adds Brave, Opera, Vivaldi, Yandex, Waterfox, and LibreWolf as browser targets.
- [Announcing Extension.js 3.0.0](https://extension.js.org/blog/announcing-3-0-0.md): Extension.js 3.0.0 ships faster Rspack-powered builds, Firefox Manifest V3 support, and first-class TypeScript for cross-browser extension development.
- [Announcing Extension.js 2.0.0-beta](https://extension.js.org/blog/announcing-2-0-0-beta.md): Extension.js 2.0.0-beta stabilizes alpha features and resolves browser compatibility issues across Firefox, Edge, and Chrome for cross-browser builds.
- [Announcing Extension.js 2.0.0-alpha](https://extension.js.org/blog/announcing-2-0-0-alpha.md): Extension.js 2.0.0-alpha introduces 30+ starter templates, browser-specific manifest fields, and SWC-powered compilation for faster builds.

## Other

- [AGENTS](https://extension.js.org/AGENTS.md)

> The links below point to documentation indexes. Follow each `/_llms/` index recursively until you reach documentation pages.

## Indexes

- [English / Documentation (132 pages)](https://extension.js.org/_llms/en/documentation.md): Documentation for English / Documentation.
- [Simplified Chinese (146 pages)](https://extension.js.org/_llms/zh-hans.md): Documentation for Simplified Chinese.
- [Simplified Chinese / Documentation (132 pages)](https://extension.js.org/_llms/zh-hans/documentation.md): Documentation for Simplified Chinese / Documentation.
- [Traditional Chinese (146 pages)](https://extension.js.org/_llms/zh-hant.md): Documentation for Traditional Chinese.
- [Traditional Chinese / Documentation (132 pages)](https://extension.js.org/_llms/zh-hant/documentation.md): Documentation for Traditional Chinese / Documentation.