Firefox for iOS is the Mozilla-maintained, Swift-written monorepo that holds the complete source for the Firefox and Focus browsers on Apple's mobile platform, released under the Mozilla Public License 2.0 and intended for iOS engineers, Mozilla contributors, and anyone who wants to build, audit, or modify the browser running on an iPhone or iPad.
What it is
This is a public GitHub repository, mozilla-mobile/firefox-ios, published under the category Productivity and Utilities, Browsers and Extensions. It is a monolithic repository, which means the source for both the Firefox for iOS project and the Focus iOS project live in one checkout rather than in separate repositories. The codebase is written in Swift, licensed under MPL-2.0, and carries 13,039 stars, 3,265 forks, and 1,827 open issues, with the most recent push recorded on 17 September 2026. The repository tags itself with browser, firefox, ios-app, mozilla, and swift, which accurately describes both the products and the toolchain.
The concrete problem it solves is access. The shipping applications are distributed only as App Store binaries, Firefox under id989804926 and Focus under id1055677337, so anyone who wants to inspect the code, reproduce a build, patch behaviour, or ship a derived browser has no path through the store. This repository replaces that closed loop with buildable source, a single checkout that covers both apps instead of two, a public issue tracker, and a documented contribution process. It lives squarely in the Apple iOS ecosystem, and it depends on the Xcode toolchain rather than on any server-side runtime.
Key capabilities
- Ships Firefox for iOS and Focus iOS in one monolithic repository, each with its own build instructions in firefox-ios/README.md and focus-ios/README.md.
- Provides an automated setup route, documented in the wiki page titled Automated Project Setup with FXIOS, as the recommended way to get a working project.
- Supports a manual route that starts by cloning the repository locally and then following the relevant project readme.
- Requires a preflight check that xcode-select -p points to /Applications/Xcode.app/Contents/Developer, or to whatever the Xcode application has been renamed.
- Distributes the compiled products through the App Store, with Firefox at id989804926 and Focus at id1055677337.
- Maintains a contributor on-ramp through the Contributor OK issue label, issue templates, CONTRIBUTING.md, and the Mozilla Community Participation Guidelines.
- Hosts live discussion on the Element channels #fx-ios and #focus-ios at chat.mozilla.org.
Who uses it and how
- Mozilla's own iOS engineers work in this repository as the primary codebase for both shipping browsers, and outside contributors file issues and open pull requests against it.
- New contributors use the Contributor OK label to find issues that maintainers have deliberately scoped as approachable first tasks.
- Developers working on both products clone the repository once and switch between the two project readmes rather than maintaining separate checkouts.
- Contributors coordinate questions and general discussion through the two Element rooms, #fx-ios and #focus-ios, or by opening a ticket when an issue template fits better.
- Organisations that need to audit or fork an MPL-2.0 mobile browser codebase use the source instead of consuming the App Store binary.
Getting started
Building requires macOS with Xcode installed, after which the recommended path is the automated project setup described in the Automated Project Setup with FXIOS wiki page; the manual alternative is to clone the repository and follow firefox-ios/README.md or focus-ios/README.md. End users who only want the browser install Firefox (id989804926) or Focus (id1055677337) from the App Store.
How it compares
The provided facts name no paid products that this project replaces, and they name no competing tools, so firefox-ios stands alone in this registry. Its only sibling is Focus iOS, which ships from the same monorepo rather than competing with it. Both are MPL-2.0, both are client applications, and neither carries a paid tier or a hosted service.
When to use it — and when not to
This is the right starting point for anyone building, auditing, or forking an iOS browser, because the source is complete and the licence is permissive in the MPL-2.0 sense. It is the wrong choice for anyone without a macOS and Xcode environment, since no Linux or Windows build path is documented, and there is no server component to self-host, so deployment always ends at the App Store. The practical weaknesses are a thin top-level readme that mostly delegates to per-project readmes and a wiki, plus a backlog of 1,827 open issues that signals how much unresolved work sits in the tracker.
