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Nimbus & Experiments

Cyndi Chin edited this page Sep 22, 2025 · 8 revisions

What is this?

Nimbus is Mozilla's platform for experimentation. This can take the form of A/B tests, different layouts, etc. Any experiment should be temporary, and, once results are in, the application code should be updated to remove the experiment and hard-code what is desired.

For more information specifically related to iOS, please see the topics found under Nimbus in the wiki home.

For documentation on Nimbus in general, please refer to the experimenter.info site.

Adding Advanced Targeting

If you are asked to add advanced targeting to be used in an experiment, here are some PRs that you can look at as an example.

Not only do we need to create a PR on our side, but we also need to create one in the experimenter repository (which you will need to fork).

As of writing this, it seems like both CI passes despite the order that they merged. We tested this theory with this PR. However, we prefer merging the PR in Firefox first.

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