“coverage” ping

This ping is not enabled by default. When enabled, a ping is generated a total of once per profile, as a diagnostic tool to determine whether Telemetry is working for users.

This ping contains no client id and no environment data.

You can find more background information in this blog post.


  "appVersion": "63.0a1",
  "appUpdateChannel": "nightly",
  "osName": "Darwin",
  "osVersion": "17.7.0",
  "telemetryEnabled": 1

Expected behaviours

The following is a list of expected behaviours for the coverage ping:

  • The ping will only be sent once per ping version, per profile.

  • If sending the ping fails, it will be retried on startup.

  • A totally arbitrary UUID is generated on first run on a new profile, to use for filtering duplicates.

  • The ping is sent to a different endpoint not using existing Telemetry.

  • The ping does not honor the Telemetry enabled preference, but provides its own opt-out preference: toolkit.coverage.opt-out.

  • The ping is disabled by default. It is intended to be enabled for users on an experimental basis using the preference toolkit.coverage.enabled.

Version History

  • Firefox 64: