This document enumerates the metrics collected by Firefox using the Glean SDK. This project may depend on other projects which also collect metrics. This means you might have to go searching through the dependency tree to get a full picture of everything collected by this project.



This ping is intended to evaluate the behaviour of FOG before it ships beyond Nightly. This is a temporary ping. It is sent one hour after FOG is initialized, and every hour thereafter.

This ping is sent if empty.

This ping includes the client id.

Data reviews for this ping:

Bugs related to this ping:

This ping contains no metrics.


This is a built-in ping that is assembled out of the box by the Glean SDK.

See the Glean SDK documentation for the metrics ping.

The following metrics are added to the ping:

Name Type Description Data reviews Extras Expiration Data Sensitivity
fog.initialization timespan Time the FOG initialization takes. 1 never 1
fog.ipc.replay_failures counter The number of times the ipc buffer failed to be replayed in the parent process. 1 never 1

Data categories are defined here.