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Firefox handles data with transparency—learn more about what that means for you. Read the Firefox Privacy Notice.
Table of Contents
What is this about?
As an independent browser, Firefox can only exist when people actively choose to use it instead of the built-in browser that comes bundled with their operating system. Unfortunately, the vendors of these operating systems often don’t play fair. Microsoft, for example, has used a number of deceptive tactics to subvert peoples’ browser choice and redirect them to the built-in browser.
On Android, Chrome comes preinstalled and users need to search for Firefox in the Google Play Store to find it. To make matters worse, Google accepts money from other companies to show their browser when a user searches for “firefox”. To combat this, Mozilla must either pay Google for placement in the Play Store, or promote direct links to the Firefox listing on other platforms like social media apps.
In both cases, Mozilla must divert money away from building Firefox to pay the companies that operate these big platforms. Mozilla can significantly reduce the amount it must pay to these platforms if it can notify them when someone they refer becomes a regular user. When Firefox detects during first-run that a user was referred by one of these platforms, it asks permission to send this notification to help future users find Firefox through these platforms and reduce what Mozilla pays the companies that operate them.
How does it work?
If you decline the request, nothing happens.
If you accept, Firefox sends an initialization message either to Mozilla or to Adjust, a vendor which interfaces with these large platforms on behalf of Mozilla. It also sends a notification when one of a handful of broad milestones are reached, like using Firefox on at least three different days within the first week. These messages are only sent for the short period of time when you first start using the browser. If and when you reach the current usage criteria, Mozilla or Adjust notifies the platform that you became a regular user of Firefox.
What data is sent?
Firefox is built on the principle that even Mozilla should never learn sensitive information about you like which websites you visit. The only information sent about your usage of Firefox is broad information like the fact that you used it for three days within the first week.
The messages contain an identifier, which tells the referring platform which specific user became a regular Firefox user. This may be a device identifier from the operating system, IP address, or a click identifier passed from the referring platform. That platform may have its own data corresponding to this user, but Mozilla does not receive such information.
The messages also include technical data like your country, operating system, and app version.
How to opt out on Android
You can opt out by simply declining the request during onboarding.
If you accept the request and change your mind, you can disable any further messages in your browser settings.
- Open Firefox and tap the menu button in the top-right corner.
- Select .
- Scroll to Privacy and Security, then tap .
- Toggle off the Campaign measurement data option at the bottom to opt out of this data collection. When you uncheck the box, a data deletion request is sent to Mozilla and/or Adjust.
