# Extension.js

Browser extension framework.

Source: [Console review](<https://console.dev/tools/extension-js>)

Website: [https://github.com/cezaraugusto/extension.js](<https://github.com/cezaraugusto/extension.js>)

Profile updated: 2026-10-16

Category: [Browser utilities](<https://console.dev/tools/categories/systems-browser-utilities>)

## Supported tech stack

Research checked: 2026-10-11

### Runs on

- Bun (Runtime)
- Deno (Runtime)
- Node.js (Runtime)

### Integrates with

- Browser (Runtime)
- JavaScript (Language)
- Preact (Framework)
- React (Framework)
- Svelte (Framework)
- TypeScript (Language)
- Vue (Framework)

Source: [Research source](<https://github.com/extension-js/extension.js>)

Documented compatibility; coverage may be incomplete. Written in describes implementation, not user-project language support.

README lists Node.js, Deno and Bun CLI runtimes and TypeScript, React, Vue, Svelte and Preact framework support for browser extensions.

## Console’s review — 2024-05-16

Reviewed: 2024-05-16

Author: [David Mytton](<https://console.dev/about#david-mytton>)

Citation: [This review](<https://console.dev/tools/extension-js#review_70e7521960e457e0a5aaf13f622f8ab63eda208b78c0ecac6a489bc598e37153>)

### What we like

Browser extension development framework. Allows you to write extensions for most browsers using TypeScript / JS, React and CSS. Supports calling into WebAssembly. Dev command supports live reload. Helps build & package for distribution.

### Tradeoffs

No support for Safari or mobile browsers like Firefox for Android & Safari on iOS.

This review reflects Console’s assessment at publication on 2024-05-16. Features and limitations may have changed since the review date.

## Is Extension.js a fit?

Based on [Console’s review published on 2024-05-16](<https://console.dev/tools/extension-js#review_70e7521960e457e0a5aaf13f622f8ab63eda208b78c0ecac6a489bc598e37153>).

Summary updated: 2026-10-16

### Who it’s for

Developers of browser extensions

### Why consider it

Allows writing extensions for most browsers using TypeScript/JS, React, and CSS

### Keep in mind

Lacks support for Safari or mobile browsers

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