Firefox collects telemetry data by default and sends this information to Mozilla, to help improve the performance and stability of Firefox. Telemetry data is made up of two data sets: interaction data and technical data.

What is interaction and technical data?

Interaction data includes information about your interactions with Firefox, such as the number of open tabs and windows, number of webpages visited, number and type of installed Firefox add-ons and session length. It also includes information about interaction with features offered by Mozilla or our partners, such as Firefox search features and search partner referrals.

Technical data includes information about your Firefox version and language, device operating system and hardware configuration, memory, basic information about crashes and errors, and outcome of automated processes such as updates and safe browsing. When Firefox sends data to us, your IP address is temporarily collected as part of our server logs. IP addresses are deleted every 14 days.

Can I learn more about telemetry data collection?

Yes! You can learn about our telemetry data collection by typing about:telemetry in the Firefox address bar. The page that opens will show you the data being sent to Mozilla for your current session. You can also see archived information.

Learn more about how we handle your data by reading the Firefox Data Documentation Overview and the telemetry documentation for Desktop. You can get additional information about specific probes in our probe dictionary which is publicly available for our users.

Any data collection or sharing adheres to our Firefox data collection policy.

To learn more about one example of how we collect and use telemetry data for Windows users, see Telemetry collection - Windows default browser trends.

How long do you keep telemetry data?

We keep telemetry data for 13 months.

How do I opt out or delete telemetry data?

You can opt out of sending any Firefox telemetry information at any time. If you opt out of sending telemetry data, we will also treat this as a request to delete any data we previously collected. Data will be deleted within 30 days after you opt out.

To opt out of sending any Firefox telemetry information:

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the Privacy & Security panel.
3. Go down to the Firefox Data Collection and Use section.

   

4. Deselect the Allow Firefox to send technical and interaction data to Mozilla checkbox.

To learn more about what data Mozilla receives and how it's used, see Mozilla's Firefox Privacy Notice.