Using locally published components in Fenix

It's often important to test work-in-progress changes to Application Services components against a real-world consumer project. The most reliable method of performing such testing is to publish your components to a local Maven repository, and adjust the consuming project to install them from there.

With support from the upstream project, it's possible to do this in a single step using our auto-publishing workflow.


Both the auto-publishing and manual workflows can be sped up significantly by using the rust.targets property which limits which architectures the Rust code gets build against. You can set this property by creating/editing the file in the repository root and adding a line like rust.targets=x86,linux-x86-64. The trick is knowing which targets to put in that comma separated list:

  • Use x86 for running the app on most emulators (in rare cases, when you have a 64-bit emulator, you'll want x86_64)
  • If you're running the android-components or fenix unit tests, then you'll need the architecture of your machine:
    • OSX running Intel chips: darwin-x86-64
    • OSX running M1 chips: darwin-aarch64
    • Linux: linux-x86-64

Using the auto-publishing workflow

mozilla-central has support for automatically publishing and including a local development version of application-services in the build. This is supported for most of the Android targets available in mozilla-central including Fenix - this doc will focus on Fenix, but the same general process is used for all. The workflow is:

  1. Ensure you have a regular build of Fenix working from mozilla-central and that you've done a ./mach build

  2. Ensure you have a regular build of application-services working.

  3. Edit (or create) the file - this can be in the root of the mozilla-central checkout, or in the project specific directory (eg, mobile/android/fenix) and tell it where to find your local checkout of application-services, by adding a line like:


    Note that the path can be absolute or relative from For example, if application-services and mozilla-central are at the same level, and you are using a in the root of mozilla-central, the relative path would be ../application-services

  4. Build your target normally - eg, in Android Studio. or using gradle

If all goes well, this should automatically build your checkout of application-services, publish it to a local maven repository, and configure the consuming project to install it from there instead of from our published releases.

Using Windows/WSL

Good luck! This implies you are also building mozilla-central in a Windows/WSL environment; please contribute docs if you got this working.

However, there's an excellent chance that you will need to execute ./automation/ from your local application-services root.


  1. This assumes you are able to build both Fenix and application-services directly before following any of these instructions.
  2. Make sure you're fully up to date in all repos, unless you know you need to not be.
  3. Contact us if you get stuck.