Several new device manufacturers and mobile carriers have lined up to support Mozilla’s mobile operating system. The software platform, which is based on Mozilla’s Boot2Gecko (B2G) project, will be called Firefox OS when it launches on handsets next year.

Mozilla began working on the B2G project last year, aiming to offer a truly open alternative to existing mobile operating systems. The B2G application stack and runtime environment are built around standards-based Web technologies instead of platform-specific development tools and frameworks.

Alongside B2G, Mozilla is also working on a complementary effort to extend Web standards with capabilities that are needed by mobile applications, such as APIs for power management and telephony. Mozilla hopes to ensure that the open Web will provide a rich platform for application development that is competitive with the native stacks supplied by rival platforms.

Telefónica became the first network operator to adopt the platform when it announced a partnership with Mozilla earlier this year. Mozilla announced several new partners today, including Deutsche Telekom, Sprint, Telecom Italia, and Telenor.

Hardware manufacturers TCL and ZTE have committed to building the first Firefox OS devices, which will use a Qualcomm Snapdragon SoC. The very first Firefox OS phone will be available to consumers in Brazil next year through Telefónica’s Vivo brand.

Ars met with Mozilla evangelist Christian Heilmann on Friday to discuss the status of the Boot2Gecko project. He explained that the platform is built to run on entry-level devices, primarily for the developing world. The idea is to give feature phone users an affordable new device that will offer a more complete Web experience.

Heilmann insists that B2G is not intended to compete with contemporary smartphone platforms such as Android and iOS. It’s worth noting, however, that Android has a growing presence in developing markets and is rapidly scaling down to work on feature phones.

During the opening keynote at Google I/O last week, the search giant touted Android’s massive growth in India, Thailand, and Brazil. It seems like Android and Firefox OS are eventually going to be rivals in those markets. The truly open and inclusive nature of B2G development could help make it attractive to carriers and handset manufacturers.

Unlike Android, Mozilla’s mobile operating system has been developed in the open since it was first announced. The code is published in a public repository as it is written, so there are no privileged parties who have more access or control than others. Mozilla’s platform also has a low barrier to entry for participation, making it more inclusive to independent contributors.

Heilmann said that the lightweight architecture of B2G makes it an ideal choice for affordable devices with lower hardware specifications than conventional smartphones. The idea that a Web-based technology stack could be less resource intensive than a platform largely built around native code may seem counterintuitive, but it works in practice.

Firefox OS is a much thinner platform, consisting of Mozilla’s Gecko HTML rendering engine, a Linux kernel, and a few background services. It doesn’t have all of the complex mobile middleware layers that are usually found in mobile operating systems. It is heavily optimized and relies on hardware-accelerated rendering to deliver good performance without heavy resource consumption.

Firefox users are accustomed to seeing the browser grow to consume multiple gigabytes of memory on the desktop during intensive browsing sessions, but the rendering engine can operate efficiently with much less. According to Mozilla, the B2G platform can run acceptably well in an environment with as little as 256MB of RAM.

We asked Heilmann several questions about the platform's capabilities. Third-party applications will be built largely with HTML and JavaScript, using open standards and the new Web APIs that Mozilla is working to turn into standards. Users will be able to install applications from Mozilla’s application marketplace and run them offline when connectivity isn’t available.

Although modern Web standards provide a lot of rich functionality for building interactive experiences, there are still some limitations and areas where the Web’s native security model will pose challenges. The lack of support for conventional TCP sockets, for example, could make it difficult to build a traditional offline IMAP e-mail client for B2G.

The platform will not come with a mail client when it ships on devices later next year, though users will be able to load various webmail services in a device’s Web browser. According to Heilmann, market research in Brazil has shown that text messaging (which is fully supported on the B2G platform thanks to new JavaScript APIs) is much more important than e-mail to Mozilla’s target audience in the region.

Firefox OS is obviously a very different critter than Android and iOS, but the growing amount of enthusiasm from mobile carriers suggests that the platform may have what it takes to succeed in the developing world.

Update: the article originally erroneously indicated that Firefox OS would ship later this year, but it was updated to reflect the expected 2013 launch date.

Update 2: Mozilla says that Heilmann was incorrect about the mail client. A new pure TCP socket API that will be available to applications is being used to build a conventional mail client that will ship with B2G.