Firefox - Developer Tools

About DevTools

DevTools is a toolbox, built-in to Firefox, for developers and designers to inspect, debug and modify Web code.

You can learn about using DevTools by reading its documentation.

DevTools is written in Javascript, HTML and CSS and has lots of opportunities to help out.

Who Works on DevTools?

A large community of volunteers throughout the world report bugs, test DevTools, submit code changes and localize the UI. The team assigned to work on DevTools at Mozilla is distributed around Europe. You will likely see the names of team members listed as mentors in the bugs and issues on this site. We are always excited to meet new Mozillians!

How Do I Get Started?

If you intend to work on a bug (in Bugzilla) or an issue (in GitHub), make sure you have an account on those sites.

Comment in the bug or issue and say that you are interesting in working on it. Ask any questions you may have. And make sure you do your research. Look the other comments, look at the documentation and source code, and try to figure out as much as you can first.

How Do I Write the Code?

Most of the code is hosted in the Firefox repository (called mozilla-central), while the Profiler is developed on GitHub.

Once you've figured out what you would like to work on, read about how to set up your local development environment.

Finally, create and send a patch for someone else to review and merge in the repository.

How Do I Get Help?

The best place to talk about a bug or issue is in the comments. Don't be afraid to ask questions or describe how you are solving the problem. That way, anyone watching the bug can answer your questions or offer useful advice.

Some bugs have an assigned mentor, and that person will usually be the one to reply.

We are also available on chat.mozilla.org.