Firefox is Mozilla's popular Web browser, available for multiple platforms including Windows, Mac OS X, and Linux on the desktop and Android mobile devices. With broad compatibility, the latest in Web technologies, and powerful development tools, Firefox is a great choice for both Web developers and end users.

Firefox is an open source project; most of the code is contributed by our huge community of volunteers. Here you will learn about how to contribute to the Firefox project and you will also find links to information about the construction of Firefox add-ons, using the developer tools in Firefox, and other tasks.

Learn how to create add-ons for Firefox, how to develop and build Firefox itself, and how the internals of Firefox and its subprojects work.

  • Developer release notes

    Developer-focused release notes; learn what new capabilities for both Web sites and add-ons arrive in each version of Firefox.

  • Project documentation

    Get detailed information about the internals of Firefox and its build system, so you can find your way around in the code.

  • Developer guide

    Our developer guide provides details on how to get and compile the Firefox source code, how to find your way around, and how to contribute to the project.

Firefox is available in four channels. The release channel is for everyday use; it's the shipped version used by millions of people around the world. The other channels are for use by testers, early adopters, and serious enthusiasts.

  • Firefox Nightly

    Nightly builds of Firefox for testing purposes only.

    Download Nightly
  • Firefox Aurora

    The newest innovations in an experimental environment.

    Download Aurora
  • Firefox Beta

    The latest features in a more stable environment.

    Download Beta
  • Firefox

    Tried, tested, and used by millions around the world.

    Download Firefox

Join the Firefox community

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