Note: The Quickstart section has been updated with a new, more focused Firefox OS app essentials article, which replaces all the previous Quickstart articles. We hope you'll find this more useful, and a quicker learning experience than the older set of articles.
Firefox OS is a new mobile operating system developed by Mozilla's Boot to Gecko (B2G) project. It uses a Linux kernel and boots into a Gecko-based runtime engine, which lets users run applications developed entirely using HTML, JavaScript, and other open web application APIs.
Firefox OS (also referred to by its codename "Boot to Gecko" or "B2G") is Mozilla's open source mobile operating system, based a Linux kernel, which boots into a Gecko-based runtime engine that lets users run applications developed entirely using HTML, CSS, JavaScript, and open web application APIs. Firefox OS is a mobile operating system that's free from proprietary technology while still a powerful platform that provides application developers an opportunity to create excellent products. In addition, it's flexible and capable enough to make the end user happy.
Firefox OS comes with a suite of pre-installed applications called Gaia, which handle the fundamental functions of the phone such as settings, calls, SMS, taking and storing photos, etc.
For Web developers, the most important part to understand is that the entire user interface is a Web app, one that is capable of displaying and launching other Web apps. Any modifications you make to the user interface and any applications you create to run on Firefox OS are Web pages, albeit with enhanced access to the mobile device's hardware and services.
Firefox OS is currently under heavy development; we are constantly working on ways to make it easier for you to use and hack on Gaia and create apps. However, you need knowledge about systems in order to do things like build the entire Firefox OS stack, or flash a phone with a build of Firefox OS. To find such information, and lots more besides, head on over to our Firefox OS content zone.