If you are new to open source or to Mozilla, you might like this tutorial for new Marionette contributors.

We are delighted that you want to help improve Marionette! ‘Marionette’ means different a few different things, depending on who you talk to, but the overall scope of the project involves these components:

  • Marionette is a Firefox remote protocol to communicate with, instrument, and control Gecko-based applications such as Firefox and Firefox for mobile. It is built in to the application and written in JavaScript.

    It serves as the backend for the geckodriver WebDriver implementation, and is used in the context of Firefox UI tests, reftesting, Web Platform Tests, test harness bootstrapping, and in many other far-reaching places where browser instrumentation is required.

  • geckodriver provides the HTTP API described by the WebDriver protocol to communicate with Gecko-based applications such as Firefox and Firefox for mobile. It is a standalone executable written in Rust, and can be used with compatible W3C WebDriver clients.

  • webdriver is a Rust crate providing interfaces, traits and types, errors, type- and bounds checks, and JSON marshaling for correctly parsing and emitting the WebDriver protocol.

By participating in this project, you agree to abide by the Mozilla Community Participation Guidelines. Here are some guidelines for contributing high-quality and actionable bugs and code.

Writing code

Because there are many moving parts involved remote controlling a web browser, it can be challenging to a new contributor to know where to start. Please don’t hesitate to ask questions!

The canonical source code repository is mozilla-central. Bugs are filed in the Testing :: Marionette component on Bugzilla. We also have a curated set of good first bugs you may consider attempting first.

We have collected a lot of good advice for working on Marionette code in our code style document, which we highly recommend you read.

Next steps

Other resources