The first devices to run Mozilla's HTML 5-based Firefox OS have been revealed as the "Keon" and the "Peak", developed in conjunction with Geekphone and Telefonica.

Rather than being full retail models, the handsets are aimed at developers who want to start building and testing apps that use the platform. Mozilla said that the first phones will be available to buy in February.

"Developer preview phones will help make the mobile web more accessible to more people. Developers are critical to the web, and to Mozilla's mission to make the web accessible to everyone," Stormy Peters, director of developer engagement at Mozilla, said in a blog post on Tuesday. "Now we are working on bringing the power of the web to mobile through Firefox OS, along with all the power of open standards and an open community, and once again, we'd like to invite web developers to join us."

The lower specced of the two devices, the Keon, will come with a Qualcomm Snapdragon S1 1GHz processor, 3.5-inch HVGA touchscreen display, 3-megapixel camera, and 4GB of internal storage. It also has the smartphone staples of microSD support, Wi-Fi (N), and GPS. It does not, however, have a forward-facing camera.

The Peak will come with a slightly higher specification that includes a dual-core 1.2GHz Snapdragon S4 processor, 4.3-inch qHD display, 8-megapixel camera on the rear, and 4GB of internal storage. It also has a forward-facing 2-megapixel camera and a higher capacity battery, too.

Mozilla announced the Firefox OS in February 2012, albeit under the name "Boot 2 Gecko" , and has since been working to secure partners for launch. Telefonica, one of the backers of the Geekphone devices, was also one of the first companies to show support for the HTML5-based OS.

Mozilla released a beta version of its Firefox OS simulator in December, but these devices will be the first real-world hardware designed specifically to run the OS.

On January 26, Mozilla will be hosting a set of "hack days" to give developers around the world the chance to "learn, hack, share, and celebrate Firefox OS", Peters said.