Open source firefox-extension projects
Every project in the registry tagged firefox-extension, ranked by real GitHub adoption.
Build AI agents and RPA workflows without writing code
Integrating ChatGPT into your browser deeply, everything you need is here
Captcha solver extension for humans, available for Chrome, Edge and Firefox
QOwnNotes is a plain-text file notepad and todo-list manager with Markdown support and Nextcloud / ownCloud integration.
The cross-browser extension framework.
Reddit Enhancement Suite
Debloated fork of the extension "I don't care about cookies"
scanner detecting the use of JavaScript libraries with known vulnerabilities. Can also generate an SBOM of the libraries it finds.
Browser extension for reverse image search, available for Chrome, Edge and Safari
👻 Use your text editor to write in your browser. Everything you type in the editor will be instantly updated in the browser (and vice versa).
Firefox/Chrome browser extension. SmartProxy will automatically enable/disable proxy for the sites you visit, based on customizable patterns.
A powerful browser extension to create, edit and delete cookies
Markdown Viewer / Browser Extension
Browser extension for viewing archived and cached versions of web pages, available for Chrome, Edge and Safari
Apollo Client browser developer tools.
Use native tab discarding method to automatically reduce memory usage of inactive tabs
StackPrism is a browser extension for detecting website technology stacks.
Privacy-focused translation with offline capabilities
😎 Browser extension that automatically replaces the User-Agent with a randomized one
⏩ Fast-forwards long pauses between sentences — watch lectures ~1.5x faster (browser extension)
The Bitcoin Lightning Browser Extension that brings deep Lightning & Nostr integration to the web. Wallet interface to multiple lightning nodes and key signer f
A fast image viewer and editor for your browser and desktop
Chrome & Firefox extension for Notion to add 20+ features like sticky outline, small text & full width by default, hide comments & help button, bolder text etc.
Related tags
Frequently asked questions
How many open source firefox-extension projects are there?
This registry tracks 23 projects tagged firefox-extension, with 89,552 GitHub stars between them. The most-adopted is Automa at 21,705 stars.
Are these firefox-extension projects free to use?
Yes — 22 of the 23 carry an explicit open-source licence across 7 distinct licences, so there is no licence fee. Where a project also sells a hosted or enterprise version, the self-hosted path remains free.
Which firefox-extension project should I choose?
The list above is ranked by GitHub stars, but stars measure attention rather than fit. Check three things on each card: the licence (permissive versus copyleft), the language it is written in, and the last-push date — a high-star project that has not been pushed in a year is a liability.
Are these firefox-extension projects still maintained?
17 of the 23 were pushed in the last 90 days, and every card shows its exact last-push date so you can see the rest. Sort your shortlist by that date before committing to a migration.