Mozilla Developers

Developer tools, resources, videos and more

Firefox Quantum: Developer Edition

Get the latest features, fast performance, and the development tools you need to build for the open web.

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Developer resources

MDN

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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Cross-browser testing

Easily test your site on every browser and operating system.

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Events to check out

Fresh from our blog

Fresh from our blog

  • The Power of Web Components

    Web Components comprises a set of standards that enable user-defined HTML elements. These elements can go in all the same places as traditional HTML. Despite the long standardization process, the emerging promise of Web Components puts more power in the hands of developers and creators.

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  • New & Experimental Web Design Tools: Feedback Requested

    We’re currently hard at work on some new tools for web designers: a comprehensive Flexbox Inspector as well as CSS change-tracking. Tell us about your biggest CSS and web design issues and pain points in the first-ever Design Tools survey from Mozilla! We want to hear from developers and designers, no matter what browser you use.

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  • Private by Design: How we built Firefox Sync

    Firefox Sync lets you share your bookmarks, browsing history, passwords and other browser data between different devices, and send tabs from one device to another. We think it’s important to highlight the privacy aspects of Sync, which protects all your synced data by default so Mozilla can’t read it, ever. In this post, we take a closer look at some of the technical design choices we made in order to put user privacy first.

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Projects we love

A new layout system for the Web.

See grids in action

Mozilla’s next-generation web engine.

Get involved

A systems programming language that is fast and safe.

Check out Rust

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

Learn more

Build exciting virtual reality Web pages using HTML.

Start building