Customize Firefox

Add-ons let millions of Firefox users enhance their browsing experience. If you know HTML, JavaScript, and CSS, you already have all the necessary skills to make a great add-on.

Learn How to Make an Add-on

Port a Chrome Extension

Firefox supports WebExtension APIs, which in most cases are compatible with the extension APIs supported by Chrome, Opera and Edge, so your extensions will run in Firefox with just a few changes.

Learn How

Publish Your Add-on

Have an add-on ready? Submit your extension or theme to be listed on addons.mozilla.org or sign and distribute your extension on your own.

Manage Your Add-on

Resources for a successful launch

You've built your extension and are ready to publish it. What comes next? Check out our tips for creating an appealing listing page, getting your extension featured on addons.mozilla.org, finding answers to development questions, and staying up-to-date with news and events relevant to extension developers.

View Resources for Publishers

Latest News

A new world of open extensions on Firefox for Android has arrived
fa 10 mesos, 3 setmanes
Open extensions on Firefox for Android debut December 14 (but you can get a sneak peek today)
fa 11 mesos, 1 setmana
Is your extension ready for Firefox for Android? Be part of the launch of a new open mobile ecosystem
fa 12 mesos
Changes to Android extension signing
fa 1 any
Test Firefox Android extensions and help developers prepare for an open mobile ecosystem in December
fa 1 any, 1 mes

Eines

Web-Ext
A command line tool to build, run, and test extensions.
Validador de complements
Automated code tests for your add-on.
Compatibility Test
Check to see if your extension is compatible with Firefox.
Live Testing
Temporarily install your extension in Firefox for live testing and debugging.