Firefox Developer Edition

Built for those who build the Web

The only browser made for developers like you.

Firefox Developer Edition — English (US)

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Firefox Developer Edition — English (US)

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Firefox Developer Edition
  • Designed for developers

    The only browser made just for developers, Firefox Developer Edition was created with your workflow in mind. Build, test, scale and more all from one place, for the first time ever.

  • Debug any browser

    Inspect and debug your app across any browser or device with Valence — a powerful, pre-installed extension that you’ll only find in Firefox Developer Edition.

  • Pixel-perfect coding

    Target screen sizes with the Responsive Design View and tweak your CSS on the fly with the built-in Style Editor for pixel-perfect coding.

All your favorite dev tools and more

Firefox Developer Edition brings your core dev tools together with some powerful new ones that will extend your ability to work across multiple platforms from one place. It’s everything you’re used to, only better. And only from Firefox.

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    Visual Editing Tools

    Visually edit CSS and HTML animations playing on the page from the Inspector panel. Verify alignment, dimensions and padding of any element using the Ruler and Measurement tools.

    Learn more about Visual Editing Tools
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    DevTools Challenger

    Use Developer Edition’s visual animation and CSS editing tools to explore the depths of the ocean and interact with the strangest of creatures.

    Try DevTools Challenger
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    Performance Tools

    Examine your web content’s frame rate, memory consumption and JS profile in a consolidated timeline view to help easily identify and troubleshoot performance bottlenecks.

    Learn more about Performance Tools
    Play the game on Codepen
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    Page Inspector

    Examine the HTML and CSS of any Web page and easily modify the structure and layout of a page.

    Learn more about Page Inspector
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    Web Audio Editor

    Inspect and interact with Web Audio API in real time to ensure that all audio nodes are connected in the way you expect.

    Learn more about Web Audio Editor
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    Web Console

    See logged information associated with a Web page and use Web Console to interact with Web pages using JavaScript.

    Learn more about Web Console
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    JavaScript Debugger

    Step through JavaScript code and examine or modify its state to help track down bugs.

    Learn more about JavaScript Debugger
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    Network Monitor

    See all the network requests your browser makes, how long each request takes and details of each request.

    Learn more about Network Monitor
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    Style Editor

    View and edit CSS styles associated with a Web page, create new ones and apply existing CSS stylesheets to any page.

    Learn more about Style Editor
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    Responsive Design View

    See how your Website or Web app will look on different screen sizes without changing the size of your browser window.

    Learn more about Responsive Design View
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    Develop and debug your apps across multiple browsers and devices with this powerful extension that comes pre-installed with Firefox Developer Edition.

    Learn more about Valence