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The best resource for the Open Web.

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Firefox DevTools

Edit and debug HTML, CSS, and JavaScript.

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WebAssembly

Use the .wasm format as a compiler target.

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Easily test your site on every browser and operating system.

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Events to Check Out

Fresh from our Blog

  • An inside look at Quantum DOM Scheduling

    Scheduling is a significant piece of Project Quantum, which focuses on making Firefox more responsive, especially when lots of tabs are open. In this article, we describe problems we identified in multi-tab browsing, the solutions we figured out, the current status of Quantum DOM, and opportunities for contribution to the project.

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  • Powerful New Additions to the CSS Grid Inspector in Firefox Nightly

    CSS Grid is revolutionizing web design. It’s a flexible, simple design standard that can be used across all browsers and devices. That’s why we built CSS Grid Inspector. We’ve been working hard on the Firefox Developer Tools Layout panel, adding powerful new features to the Grid Inspector and Box Model. The latest enhancements are now available in Firefox Nightly.

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  • Designing for performance: A data-informed approach for Quantum development

    What makes work on performance so challenging and why is it so important to include the user from the very beginning? This article explores the difference between technical and perceived performance, and describes an approach to testing and measurement that correlates the user’s quality of experience with characteristics that engineers can benchmark.

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Mozilla’s next-generation web engine.

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A systems programming language that is fast and safe.

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Powerful Web technologies that help push games to the new level.

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Build exciting virtual reality Web pages using HTML.

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