Work in Progress

This article is a work in progress. The work is being tracked in this bug.

Guide to our Experimental Tools


  • Shield is an addon-based experimentation platform with fine-tuned enrollment criteria. The system add-on landed in FF 53.
  • For the moment, it sends back data in its own shield type ping, so there's lots of flexibility in data you can collect.
  • Uses the Normandy server to serve out study “recipes” (?)
  • Annotates the main ping in the environment/experiments block
  • The shield system is itself a system add-on, so rolling out changes to the entire system does not require riding release trains
  • Strategy and Insights ( team are product owners and shepherd the study development and release process along
  • Opt-out experiments should be available soon?
  • Further reading:

Preference Flipping experiments

Uses Normandy, requires NO additional addon as long as a preference rides the release train


Survey mechanism, also run via Normandy

Telemetry Experiments

Pre-release only


Custom builds of Firefox that are served to some percentage of the direct download population