Open source extension projects
Every project in the registry tagged extension, ranked by real GitHub adoption.
Open-Source Chrome extension for AI-powered web automation. Run multi-agent workflows using your own LLM API key. Alternative to OpenAI Operator.
A powerful browser extension to create, edit and delete cookies
A High-Fidelity Web Archiving Extension for Chrome and Chromium based browsers!
A Chrome 🌐 & Firefox 🦊 extension to discover the latest developer news and tools in one tab!
📦 Clients for building books with EpubPress.
Browser extension that automatically notifies and redirects you to independent wikis.
Related tags
Frequently asked questions
How many open source extension projects are there?
This registry tracks 6 projects tagged extension, with 19,015 GitHub stars between them. The most-adopted is nanobrowser at 13,810 stars.
Are these extension projects free to use?
Yes — 6 of the 6 carry an explicit open-source licence across 4 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 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 extension projects still maintained?
6 of the 6 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.