Open Source Web Browser Extensions

How are you?

Now I bring you a list of open source web browser extensions that work for any browser, be it Chrome, Firefox, Edge, Opera or another browser.

Remember that if you use a Chromium-based browser (such as Brave or Vivaldi), use the Chrome Web Store extension, or if you use a Firefox-based browser (such as LibreWolf, Waterfox, Floorp or Zen), use the Firefox add-ons extension, although the Chrome Web Store extensions also work in Edge and Opera

So enjoy this list!

If I'm missing any, comment, I'll be updating it.

Remember that you can also find more extensions at WebExtension.org and MyBrowserAddon

AxelFOSS
AxelFOSSList by AxelFOSS, last updated 
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  1. Ad-Blockers

  2. This efficient browser add-on blocks ads, trackers, and malware by default employing various filter lists, acting as a comprehensive wide-spectrum blocker.

    Cost / License

    • Free
    • Open Source

    Application types

    Platforms

    • Microsoft Edge
    • Vivaldi
    • Google Chrome
    • Pale Moon
    • Thunderbird
    • Opera
    • Node.JS
    • Chromium
    • Mozilla Firefox
    uBlock Origin screenshot 1
    uBlock Origin screenshot 1
  3. uBlock Origin Lite, also called uBO Lite or uBOL, is a permission-less MV3-based content blocker.

    Cost / License

    • Free
    • Open Source

    Application types

    Platforms

    • iPhone
    • iPad
    • Microsoft Edge
    • Google Chrome
    • Safari
    uBlock Origin Lite screenshot 1
    uBlock Origin Lite screenshot 1
  4. AdGuard icon
     Like

    AdGuard is the best way to get rid of intrusive ads and online tracking, and to protect your computer from malware. Make your web surfing faster, safer and more comfortable with AdGuard!.

    Cost / License

    • Freemium
    • Open Source

    Application types

    Platforms

    • Mac
    • Windows
    • Android
    • iPhone
    • Chrome OS
    • Android Tablet
    • iPad
    • Vivaldi
    • Google Chrome
    • Safari
    • Yandex Browser
    • Opera
    • Mozilla Firefox
    • Snapcraft
    • Microsoft Edge
    • Android TV
    AdGuard screenshot 1
    Very good app for blocking ads. Use it!
    AdGuard screenshot 2
    +4
    AdGuard screenshot 3
  5. Password Managers

  6. Bitwarden icon
     Like

    Open-source password manager with AES-256 encryption and device sync. Store and access encrypted logins across platforms like iOS and Android.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Self-Hosted
    • Apple Watch
    • Snapcraft
    • Microsoft Edge
    • Vivaldi
    • Google Chrome
    • Flathub
    • Microsoft SQL Server
    • Tor Browser
    • Safari
    • F-Droid
    • Software as a Service (SaaS)
    • Flatpak
    • Cloudron
    • Opera
    • Chocolatey
    • Mono
    • Brave
    • Mozilla Firefox
    • Docker
    Bitwarden screenshot 1
    Bitwarden screenshot 1
    Bitwarden screenshot 2
    +10
    Bitwarden screenshot 3
  7. A password manager that ensures identity and password security with rigorous, end-to-end encryption, built by scientists from CERN, and recommended by the United Nations.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Google Chrome
    • Flathub
    • Safari
    • F-Droid
    • Mozilla Firefox
    • Snapcraft
    Proton Pass screenshot 1
    Proton Pass screenshot 1
    Proton Pass screenshot 2
    +3
    Proton Pass screenshot 3
  8. KeePassXC icon
     Like

    KeePassXC is a modern, secure, and open-source password manager that stores and manages your most sensitive information.

    Cost / License

    • Free
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • AppImageHub
    • Snapcraft
    • Microsoft Edge
    • Google Chrome
    • Flathub
    • PortableApps.com
    • Flatpak
    • Homebrew
    • Chocolatey
    • Mozilla Firefox
    Welcome Screen
    Unlock Database
    New Database Wizard
    +13
    New Database Wizard
  9. VPN

  10. Swiss-based VPN that ensures online privacy with a high-speed network, advanced encryption, and no-logs policy, offering a free version. Supports multiple platforms and unblocks content worldwide.

    Cost / License

    • Freemium
    • Open Source

    Application types

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • iPhone
    • Chrome OS
    • Android Tablet
    • iPad
    • Google Chrome
    • Apple TV
    • Flathub
    • F-Droid
    • Android TV
    • Flatpak
    • Fire TV
    • Mozilla Firefox
    Proton VPN screenshot 1
    Proton VPN on Fedora
    Proton VPN screenshot 2
    +6
    Proton VPN screenshot 3
  11. Download Managers

  12. With this app, you can easily download files from anywhere. Enjoy fast, free downloads with seamless browser extension support.

    Cost / License

    • Free
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • Microsoft Edge
    • Google Chrome
    • Brave
    • Chromium
    • Mozilla Firefox
    AB Download Manager screenshot 1
    AB Download Manager screenshot 1
    AB Download Manager screenshot 2
  13. Gabut Download Manageran application made to help download activities that support all. can be used to download torrents and so on.

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Linux
    Gabut Download Manager screenshot 1
    Gabut Download Manager screenshot 1
    Gabut Download Manager screenshot 2
  14. DownThemAll (or just dTa) is a powerful yet easy-to-use browser extension for Firefox, Chrome and Opera that adds new advanced download capabilities to your browser. DownThemAll lets you download all the links or images contained in a webpage and much more: you can refine your...

    Cost / License

    • Free
    • Open Source

    Platforms

    • Microsoft Edge
    • Google Chrome
    • Pale Moon
    • Mozilla Firefox
    DownThemAll screenshot 1
    DownThemAll screenshot 1
  15. YouTube Tools

  16. SponsorBlock is a browser extension and open API via crowdsource for skipping sponsor segments in YouTube videos. It's open-source. Users submit when a sponsor happens from the extension, and the extension automatically skips sponsors it knows about using a privacy...

    Cost / License

    • Free
    • Open Source

    Application types

    Platforms

    • Online
    • Android
    • iPhone
    • Microsoft Edge
    • Google Chrome
    • Safari
    • Opera
    • Mozilla Firefox
    SponsorBlock screenshot 1
    SponsorBlock screenshot 1
  17. Returns the ability to see dislike statistics on YouTube.

    Cost / License

    • Free
    • Open Source

    Platforms

    • Online
    • Google Chrome
    • Mozilla Firefox
    • Tampermonkey
    Return YouTube Dislike screenshot 1
    Return YouTube Dislike screenshot 1
  18. Privacy

  19. NoScript icon
     Like

    The NoScript Firefox extension provides extra protection for Firefox, Seamonkey and other mozilla-based browsers: this free, open source add-on allows JavaScript, Java, Flash and other plugins to be executed only by trusted web sites of your choice (e.g. your online bank).

    Cost / License

    • Free
    • Open Source

    Application types

    Platforms

    • Mac
    • Windows
    • Linux
    • BSD
    • Google Chrome
    • SeaMonkey
    • Mozilla Firefox
    Diablog of blocked scripts
    NoScript Anwhere (Firefox Mobile version).
  20. The Mullvad Browser is a privacy-focused web browser developed in a collaboration between Mullvad VPN and the Tor Project. It’s designed to minimize tracking and fingerprinting. You could say it’s a Tor Browser to use without the Tor Network.

    Cost / License

    • Free
    • Open Source

    Application types

    Platforms

    • Mac
    • Windows
    • Linux
    • Flathub
    • Flatpak
    • Mozilla Firefox
    Mullvad Browser screenshot 1
    Mullvad Browser screenshot 1
    Mullvad Browser screenshot 2
    +1
    Mullvad Browser screenshot 3
  21. Privacy Badger is a browser-add on tool that analyzes sites to detect and disallow content that tracks you in an objectionable, non-consensual manner. When you visit websites, your copy of Privacy Badger keeps note of the "third party" domains that embed images...

    Cost / License

    • Free
    • Open Source

    Application types

    Platforms

    • Microsoft Edge
    • Google Chrome
    • Opera
    • Mozilla Firefox
    Overview of Privacy Badger extension
  22. "Terms of Service; Didn't Read" (short: ToS;DR) is a project started in June 2012 to help fix the "biggest lie on the web": almost no one really reads the terms of service we agree to all the time.

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Mac
    • Online
    • iPhone
    • Microsoft Edge
    • Vivaldi
    • Google Chrome
    • Safari
    • Tor
    • Opera
    • Brave
    • Mozilla Firefox
    • Android
    • F-Droid
    Website
Home Page
    Website
How it works
    Website 
Grade filter
    +16
    Website
Service details
  23. Note-taking Tools

  24. Joplin icon
     Like

    Open source note-taking app with Markdown support, to-do integration, and synchronization with cloud services like Dropbox and OneDrive.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Self-Hosted
    • AppImageHub
    • Snapcraft
    • Google Chrome
    • Flathub
    • PortableApps.com
    • F-Droid
    • Cloudron
    • Homebrew
    • Chocolatey
    • Termux
    • Mozilla Firefox
    Desktop and mobile apps
    Example
    Cli version!
    +3
    Table inside table with KaTeX Math notations.
(Live-editing with Vim)
  25. Notesnook icon
     Like

    Notesnook is a simple and cross-platform private notes app that keeps your notes organized and synced on your phone, tablet and computer. Take notes, capture ideas, create to-do lists, keep a journal, write your assignments and manage projects, we have got you covered.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Google Chrome
    • Flathub
    • F-Droid
    • Software as a Service (SaaS)
    • Flatpak
    Notesnook screenshot 1
    Notesnook screenshot 1
    Notesnook screenshot 2
    +6
    Notesnook screenshot 3
  26. Userscripts

  27. Greasemonkey is a Firefox extension that allows you to customize the way webpages look and function.

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Mozilla Firefox
    Greasemonkey screenshot 1
    Greasemonkey screenshot 1
    Greasemonkey screenshot 2
  28. Email Aliases

  29. addy.io icon
     Like

    Open-source anonymous email forwarding, create unlimited email aliases for free.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Self-Hosted
    • Microsoft Edge
    • Google Chrome
    • Safari
    • F-Droid
    • Software as a Service (SaaS)
    • Mozilla Firefox
    Manage aliases from the dashboard
    The main interface for the Firefox extension
    Settings for the extension
    +1
    Generate Random Chars alias using the extension.
  30. Open source solution to protect your personal email address. Generous free plan with uncapped bandwidth and infinite sends/replies, self-hostable, lot of powerful features, open roadmap, you can count on SimpleLogin to guard your email inbox.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Self-Hosted
    • Microsoft Edge
    • Google Chrome
    • Safari
    • F-Droid
    • Mozilla Firefox
    Open source solution to protect your email address.
    Create alias quickly with SimpleLogin Chrome & Firefox extension.
    Alias management dashboard.
    +1
    Visualize all emails sent to or replied from an alias.
  31. Others

  32. Cross-platform, free media player supports multimedia files, DVDs, streaming, offers hardware acceleration, 4K, lossless audio, and more.

    Cost / License

    • Free
    • Open Source

    Application types

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • iPhone
    • Android Tablet
    • BSD
    • iPad
    • AppImageHub
    • Apple Watch
    • Snapcraft
    • Google Chrome
    • Apple TV
    • Flathub
    • PortableApps.com
    • F-Droid
    • Kindle Fire
    • Haiku
    • Android TV
    • Homebrew
    • Chocolatey
    • HUAWEI AppGallery
    VLC Media Player screenshot 1
    VLC Media Player screenshot 1
    VLC Media Player screenshot 2
    +4
    VLC Media Player screenshot 3
  33. This eye-care extension enables night mode creating dark themes for websites on the fly. Dark Reader inverts bright colors making them high contrast and easy to read at night.

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • iPhone
    • iPad
    • Microsoft Edge
    • Google Chrome
    • Safari
    • Thunderbird
    • Mozilla Firefox
    Dark Reader screenshot 1
    Dark Reader screenshot 1
    Dark Reader screenshot 2
    +1
    Dark Reader screenshot 3
  34. An AI-powered proofreading tool supports over 20 languages, offering free and premium versions with extensive grammar checks across multiple apps.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • iPhone
    • iPad
    • Microsoft Edge
    • ONLYOFFICE
    • Google Chrome
    • Microsoft Outlook
    • Safari
    • Visual Studio Code
    • Microsoft Word
    • Eclipse
    • TinyMCE
    • Google Docs
    • Thunderbird
    • Vim
    • Sublime Text
    • GNU Emacs
    • Opera
    • Gmail
    • LibreOffice
    • Apache OpenOffice
    • Mozilla Firefox
    • LibreOffice - Writer
    • Cloudron
    LanguageTool screenshot 1
    LanguageTool screenshot 1
    LanguageTool screenshot 2
    +4
    LanguageTool in OpenOffice.org 3.x
  35. SingleFile is an extension that helps you to archive a complete page into a single HTML file or HTM-File with Google Chrome and Chromium.

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Microsoft Edge
    • Google Chrome
    • Safari
    • Mozilla Firefox
    SingleFile screenshot 1
    SingleFile screenshot 1
  36. PDF Viewer (aka pdf.js) is a new revolutionary extension using web standard technologies that allows you to display within Mozilla Firefox icon Mozilla Firefox almost all PDF files found on the web without a plugin.

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Google Chrome
    • Opera
    • Mozilla Firefox
    Firefox PDF Viewer (PDF.js) screenshot 1
    Firefox PDF Viewer (PDF.js) screenshot 1
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