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Vulpes OS

Firefox OS fork · Open source

Website · Downloads · Changelog · Report a bug

Vulpes OS picks up where Firefox OS left off, adapting Gaia, its interface and HTML/CSS/JavaScript applications, to run on a recent Gecko engine.

I’m OverSu, and I develop Vulpes mostly on my own, with help from people who test and contribute to the project. Vulpes is free and open source, and will stay that way. There are no plans for subscriptions or paid features.

Gaia home screen and Settings · screenshots from the desktop version.

Try Vulpes

Platform	How to use it
Linux	Run Gaia from source to explore the interface or develop applications.
Android	Install the APK from the releases page. It runs as an Android application and does not replace your phone’s operating system.
Google Pixel 3a · Sargo	Run Vulpes as a native operating system with Tundra. A downloadable image is still being prepared; see the device page for tested features and known limitations.

On the Pixel 3a, Tundra boots Gecko and Gaia directly and provides access to the hardware. Droidian was used as a testing environment early in development. It is not included in Vulpes OS, and Tundra is not based on it.

Preview 20 · 13 October 2026

Download the APK. Shared updates cover Gaia settings, camera recording, contacts and media. Native network changes are included in the sources. See the changelog for checks and remaining limitations.

Desktop/Sargo use Gecko 156.0.1; Android uses GeckoView 156.0. Android 8 / API 26 minimum is declared; not every device is tested. Calls and SMS open Android applications. The APK is a signed development build, with debugging through authorized ADB.

Linux

You’ll need Linux x86_64, Git, Python 3 and the system libraries required by Firefox.

git clone https://nnsprod.com/git/oversu/VulpesOS.git
cd VulpesOS
./setup.sh
./run.sh

setup.sh downloads the Gecko engine selected for this version and verifies its checksum.

Build the APK

From the repository root:

cd android
./build-apk.sh

The development APK is created in android/dist/. A personal build uses its own signing key, so it cannot update an APK signed with the project’s key.

Contribute

You can test Vulpes, report an issue, improve translations or contribute code. When reporting a bug, include your platform, the version you’re using and the steps to reproduce it.

Development updates and test results are in the changelog. If you’d like to help cover project costs, the Support me page explains what your contribution supports.

Credits and licenses

Thanks to Mozilla, Gaia contributors, Capyloon, Droidian, UBports, libhybris, Debian and AOSP for the code, tools and work that have helped this project.

New Vulpes code is licensed under MPL 2.0. Gaia retains its Apache 2.0 license; other components retain their own licenses and notices. See LICENSE, NOTICE and Gaia’s license.

Vulpes OS is an independent project by OverSu / NNS Production, with no affiliation with Mozilla.