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20 Most Popular Open-Source Browser & Web Extension Projects

The most-starred open-source browser extensions and web projects — ad/tracker blockers, password managers, devtools and canvas apps — with GitHub links and star counts.

By The DevFixPro Editorial Team · independent editorial research project

Star counts retrieved from the GitHub API on 2026-08-17. Open-source projects grow daily, so treat the numbers as a snapshot — always check the linked repository for the latest figures, license, and activity.

The browser is where most work happens, and open source powers many of its best add-ons. The 20 projects below are ranked by GitHub stars (fetched 2026-08-17) — privacy blockers, password managers, productivity extensions and browser-based apps. Each links to its repository.

Prefer extensions whose source you can audit: ad/tracker blockers, script managers and devtools are the highest-leverage installs for most developers.

  1. 1uBlock Origin on GitHub
    uBlock Origin★ 67,034
    By Raymond Hill (gorhill)

    Efficient, wide-spectrum content blocker (no coin).

    View on GitHub →
  2. 2Dark Reader on GitHub
    Dark Reader★ 22,270
    By Alexander Shutau

    Inverts brightness and applies dark themes to any site.

    View on GitHub →
  3. 3Bitwarden (Browser) on GitHub
    Bitwarden (Browser)★ 13,604
    By Bitwarden

    Open-source password manager browser extension.

    View on GitHub →
  4. 4Vimium on GitHub
    Vimium★ 26,775
    By Vimium Contributors

    Add keyboard shortcuts to navigate the web with Vim bindings.

    View on GitHub →
  5. 5Refined GitHub on GitHub
    Refined GitHub★ 31,940
    By Sindre Sorhus

    Simplifies and enhances the GitHub interface.

    View on GitHub →
  6. 6Violentmonkey on GitHub
    Violentmonkey★ 8,742
    By Violentmonkey Team

    Open-source userscript manager for the browser.

    View on GitHub →
  7. 7Stylus on GitHub
    Stylus★ 6,826
    By OpenStyles

    Redesign your favorite sites with custom user styles.

    View on GitHub →
  8. 8Privacy Badger on GitHub
    Privacy Badger★ 3,808
    By Electronic Frontier Foundation

    Automatically blocks invisible trackers.

    View on GitHub →
  9. 9SponsorBlock on GitHub
    SponsorBlock★ 13,648
    By Ajay Ramachandran

    Crowdsourced skip button for YouTube sponsors.

    View on GitHub →
  10. 10Vimium C on GitHub
    Vimium C★ 4,532
    By gdh1995 (Dahan Gong)

    Enhanced Vimium with extra features for keyboard-driven web navigation.

    View on GitHub →
  11. 11PDF.js on GitHub
    PDF.js★ 53,740
    By Mozilla

    PDF viewer built on open web standards (no plugins).

    View on GitHub →
  12. 12hls.js on GitHub
    hls.js★ 16,876
    By video-dev

    JavaScript HLS client for playback in browsers.

    View on GitHub →
  13. 13web-ext on GitHub
    web-ext★ 3,126
    By Mozilla

    Command-line tool to build, run, test and publish browser extensions.

    View on GitHub →
  14. 14Excalidraw on GitHub
    Excalidraw★ 129,846
    By Excalidraw

    Virtual whiteboard for sketching diagrams with a hand-drawn feel.

    View on GitHub →
  15. 15tldraw on GitHub
    tldraw★ 49,815
    By tldraw Inc.

    Infinite-canvas whiteboard SDK and app.

    View on GitHub →
  16. 16Tabliss on GitHub
    Tabliss★ 2,777
    By Tabliss

    Minimal, beautiful new-tab page for your browser.

    View on GitHub →
  17. 17Marinara on GitHub
    Marinara★ 2,455
    By schmich

    Pomodoro timer extension for focus and breaks.

    View on GitHub →
  18. 18Octotree on GitHub
    Octotree★ 23,232
    By OctoTree

    GitHub tree view in the side panel for faster code review.

    View on GitHub →
  19. 19Lighthouse on GitHub
    Lighthouse★ 30,669
    By Google Chrome

    Automated auditing for performance, accessibility and SEO.

    View on GitHub →
  20. 20React DevTools on GitHub
    React DevTools★ 11,010
    By Meta

    Browser extension to inspect React component hierarchies.

    View on GitHub →

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