Zones

MDN zones provide you one-stop access to information about specific topic areas or products. Here's a list of all the zones available to you.

Web and app development

App Center: Learn how to create open Web apps—rich experiences that run across multiple devices and form factors—using the same Web standards and open technologies you already know.
Developer tools: Learn how to use the Firefox developer tools to debug, test, and optimize your Web apps and sites.
Firefox Marketplace: An open, non-proprietary online marketplace for Web applications built using HTML, CSS, and JavaScript. Submit apps to the Firefox Marketplace or use the code to build your own marketplace.
Game development: Learn how to develop games for the Web, how to port existing games to Web technologies, and how to turn your games into Web apps.

Emscripten: An LLVM to JavaScript compiler; this lets you compile, for example, C++ code into JavaScript code which can be run in any Web browser.
L20n: A JavaScript localization framework for unleashing your natural language's power with simple code.
The MDN project: The Mozilla Developer Network (this site) relies on its community of readers and contributors to grow and improve. You can learn here how to help use, contribute to, and build the code behind MDN!1
Persona: A new simple, privacy-sensitive single-sign in system developed by Mozilla which lets users log into your Web site using their email address, freeing you from password management.

Add-ons: Learn how to build and install extensions, themes, and plug-ins for Mozilla-based software, including the popular Firefox Web browser.
Firefox: Learn all about Firefox, from how to build and revise it to how to build add-ons specifically for it.
Firefox OS: A new mobile operating system developed by Mozilla which lets users install and run open Web applications created using HTML, CSS, and JavaScript.