# Guide to our Experimental Tools

## Shield

• 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 (strategyandinsights@mozilla.com) team are product owners and shepherd the study development and release process along
• Opt-out experiments should be available soon?

## Preference Flipping experiments

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

## Heartbeat

Survey mechanism, also run via Normandy

## Funnelcake

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