You can now try Firefox OS on your Android handset without flashing a ROM on your device. Mozilla has released a developer preview of its mobile operating system that can be installed on Android devices as an app.
Firefox OS 2.5 Developer Preview acts as an Android launcher that can replace one's current home screen to replicate Firefox OS' interface and bring additional features. Users also get access to Firefox's Marketplace from where they can download apps and add-ons.
Users also get access to the Firefox Browser, which comes loaded with many privacy-centric features including the ability to enable tracking protection from websites and advertisers. The browser also lets you pin shortcuts to the websites you like on the home screen - turning them into Web apps.
In our test, we observed that the app was slightly slow - which is understandable as the app is in its preview phase. The app also seems to have been designed for an entry-level handset that presumably comes with a low-resolution screen. On our test Android device with FHD display, the icons and the interface in general appeared to be blown up. Even after making some adjustment in the settings, things still looked bloated.
For those unware, Firefox OS is an open-source, Linux-based mobile operating system meant for smartphones. The lightweight operating system uses open Web standards such as HTML5 and open Web APIs. It was first unveiled in February 2012, since then a handful OEMs have launched Firefox OS-powered handsets, with India's Intex and Spice being some of the recent partners.
Over the years, the traction of Mozilla's mobile operating system has remained negligible. A ROM for Firefox OS has been available for quite some time, but it required users to manually flash their device and replace the existing Android software. The move to make it available as an app could give Firefox OS more exposure.
The installation file weighs around 90MB and is available for download from the company's website (and not the Play Store).
Catch the latest from the Consumer Electronics Show on Gadgets 360, at our CES 2026 hub.