It's helpful for Mozilla's engineers to be able to measure how Firefox for Android and Firefox OS behave in the real world. The Telemetry feature provides this capability by sending performance and usage info to us. As you use Firefox, Telemetry measures and collects non-personal information, such as memory consumption, responsiveness timing and feature usage. It then sends this information to Mozilla on a daily basis and we use it to make Firefox better for you.

For more about what kind of information is collected and how it's used, see our privacy policy.

How do I opt-in or opt-out of sending performance data?

Using Firefox on an Android phone

You can turn this feature on or off at any time in your Settings:

1. Tap the Menu button below the screen, select More and then choose Settings.

2. Check or uncheck the box next to Send performance data in the Privacy & Security section of your Firefox Settings.

Using a Firefox OS phone

You can turn this feature on or off at any time in your Settings:

1. Tap the [Home] button below your screen, find the Settings app (usually on the first page, right of the home screen)
   
2. Find and open the Improve Firefox OS section at the bottom, under the Device category
3. Check or uncheck the box next to Submit performance data