Addfox

Addfox is a browser extension development framework for developers and AI. It is built on Rsbuild and is described as fast, simple, and free, with the stated aim of accelerating browser extension development.

Its development workflow includes a dev server, hot reload, and a dedicated reloader for extension updates. The page says both content_script and background can achieve ultra-fast HMR, and it shows an extension reload flow during development. Addfox also supports mainstream Chromium-based browsers and Firefox, auto-detects the browser install path, and can launch without configuration. A build automatically outputs a zipped extension package for installation and distribution.

The framework is presented as framework agnostic, with support for Vanilla, Vue, React, Preact, Svelte, Solid, and React plus UnoCSS. It also includes a createContentUI method for integrating content UIs using Iframe, ShadowDom, and native content. For testing and analysis, Addfox includes built-in support for Rsdoctor and Rstest for bundle analysis, unit testing, and end-to-end testing. For AI use, it provides structured metadata, terminal error output, llms.txt and markdown metadata support, and an AI-friendly error monitor that works with --debug and can capture extension errors without browser DevTools. The page also mentions Skills for migration, best practices, debugging, and testing.

Addfox is available through npx addfox@latest create and addfox dev. The page describes it as free, but does not provide any other pricing or licensing details.