Mozilla Firefox Developer Edition is a specialized web browser designed for web developers and designers. It offers a range of tools that enhance the development experience, including a responsive design mode, CSS Grid layout visualization, and advanced debugging options. The browser is built on the same engine as the standard Firefox but includes additional features tailored for front-end development.

This edition is free to use and is available on the Mac platform, providing an optimized environment for testing and building web applications. Users can access experimental features, such as CSS and JavaScript enhancements, before they are rolled out in the standard version. The browser also supports various add-ons, allowing developers to customize their workflow efficiently.