Firefox Quantum: Developer Edition

Welcome to your new favorite browser. Get the latest features, fast performance, and the development tools you need to build for the open web.

Firefox Developer Edition — English (US)

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Firefox Developer Edition — English (US)

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Faster Performance

A Next-Generation CSS Engine

Firefox has been rebuilt from the ground up to be faster and more powerful than ever. This includes a new CSS engine that has state-of-the-art innovations and is blazingly fast.

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New Tools

Firefox DevTools

The new Firefox DevTools are powerful, flexible, and best of all, hackable. This includes a best-in-class JavaScript debugger, which can target multiple browsers and is built in React and Redux.

Innovative Features

Master CSS Grid

Firefox is the only browser with tools built specifically for building and designing with CSS Grid. These tools allow you to visualize the grid, display associated area names, preview transformations on the grid and much more.

Design. Code. Test. Refine.

Build and Perfect your sites
with Firefox DevTools

Speak up

Feedback makes us better. Tell us how we can improve the browser and Developer tools.

Join the conversation

Get involved

Help build the last independent browser. Write code, fix bugs, make add-ons, and more.

Start now

Download the Firefox browser made for developers