The LibreJS project is seeking more JavaScript programmers to help maintain this browser extension. If you want to help, send an email to <>.


GNU LibreJS aims to address the JavaScript problem described in Richard Stallman's article The JavaScript Trap. LibreJS is a free add-on for GNU IceCat and other Mozilla-based browsers. It blocks nonfree nontrivial JavaScript while allowing JavaScript that is free and/or trivial.



It will add LibreJS to GNU IceCat or any Mozilla browser. You just need to give it the permissions it requires.

Latest installer

LibreJS is also available at the Mozilla Add-ons site. Due to Mozilla's review process, the version of LibreJS available at the Add-ons site is often outdated. This isn't in our control.

As with all Mozilla add-ons, disabling or removing LibreJS can be done without restarting the browser, via the Tools/Add-ons menu. This is even simpler in IceCat: the front page has a switch to enable and disable LibreJS.

Source files

They can be found on the main GNU download server (HTTPSHTTPFTP), and its mirrors. The automatic mirror selector will choose one for you.

Latest source

Releasing Your JavaScript as Free Software

If you administer a website, please read instructions on how to set your JavaScript free so that it respects your users' freedom. This is also documented in this section of the LibreJS manual.


Documentation for LibreJS is available online, as is documentation for most GNU software.

Contact Us

LibreJS has the following mailing lists:

  • bug-librejs for discussing most aspects of LibreJS, including development and enhancement requests, as well as bug reports;
  • help-librejs for general user help and discussion.

Announcements about LibreJS and most other GNU software are made on info-gnu (archive).

Security reports that should not be made immediately public can be sent directly to the maintainer. If there is no response to an urgent issue, you can escalate to the general security mailing list for advice.

There is also an Internet Relay Chat (IRC) channel named #gnu-librejs located on the Libera.Chat network.

Getting Involved

Development of LibreJS, and GNU in general, is a volunteer effort, and you can contribute. For information, please read How to help GNU. If you'd like to get involved, it's a good idea to join the discussion mailing list (see above).

Test releases
Trying the latest test release (when available) is always appreciated. Test releases of LibreJS can be found on the GNU “alpha” server (HTTPSHTTPFTP).
For development sources, issue trackers, and other information, please see the LibreJS project page at

LibreJS development happens in its Git repository. You can clone that repo with the command:

 git clone git:// 

If you prefer a web-based development workflow, there is also a repository on You can clone that repo with the command:

 git clone
LibreJS is currently being maintained by Ruben Rodriguez and Yuchen Pei. Please use the mailing lists for contact.
Special thanks go to GNU Chief Webmaster Jason Self for his feedback, testing, and support.


LibreJS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.