After a year and a half of work, Mozilla unveils its browser-based mobile operating system at Mobile World Congress. It won't win many iOS and Android faithful, but it's credible for low-budget feature-phone owners.

The ZTE Open is one of the lower-end phones that will bring Firefox OS to developing markets later this year.

(Credit: Stephen Shankland/CNET)

BARCELONA, Spain--Firefox OS is real, and it works.

Mozilla's browser-based phone technology is a credible option for the emerging markets where it'll first arrive starting in the second quarter. The non-profit debuted the first version of the software at the Mobile World Congress show in front of 700 people curious to see how well it works. For that mobile-savvy audience, the answer is this: not well enough. For wealthier customers, Firefox OS will have a hard time standing up to the two powerhouses of the mobile market, Google's Android and Apple's iOS. With Firefox OS, Mozilla is in a race to improve its software and attract developers and partners faster than its rivals spread to the low-end smartphone market. Major allies like Telefonica, Deutsche Telekom, Telenor, and China Mobile will help spread Firefox OS around the world to markets where feature phones still rule. Firefox OS looks familiar to anyone who's used Android and iOS: when you turn it on, you're faced with the familiar grid of apps. Swiping left and right slides in other pages of apps. And across the bottom of each page is a fixed set of four apps... [Read more]