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.

More about WebAssembly

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

  • Faster smarter JavaScript debugging in Firefox DevTools

    Script debugging is one of the most powerful and complex productivity features in the web developer toolbox. Done right, it empowers developers to fix bugs quickly and efficiently. The DevTools Debugger team – with help from our tireless developer community – has just landed updates that significantly improve performance and reliability.

    Read more

  • Empowering User Privacy and Decentralizing IoT with Mozilla WebThings

    In designing Mozilla WebThings, we have consciously insulated users from servers that could harvest their data, including our own Mozilla servers, by offering an interoperable, decentralized IoT solution. Learn about the user research that informs our project, and how we’ve engineered privacy by design into every aspect of Mozilla WebThings.

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  • TLS 1.0 and 1.1 Removal Update

    As you may have read last year, Safari, Firefox, Edge and Chrome browsers are removing support for TLS 1.0 and 1.1 in March of 2020. That means there’s less than a year to enable TLS 1.2 (and, ideally, 1.3) on your servers, otherwise all major browsers will display error pages, rather than the content your users came to see.

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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