Mozilla is a nonprofit project and global community building a better internet. Mozilla Stumbler is an open-source wireless network scanner that collects GPS data for the Mozilla Location Service, our crowd-sourced location database. As you move around, the app "stumbles" upon new Wi-Fi networks and cell towers. The Mozilla Location Service combines these wireless network measurements to provide geolocation services for Firefox and other open source projects. For more information, visit our project page:

How to use Mozilla Stumbler
• The app stops/pauses automatically when you are not moving or your battery is low. (This feature works better on newer devices as they have better sensors).
• Go to un-stumbled areas (not covered in blue) to fill in the coverage map:
• Improve the accuracy of the service by stumbling in the blue areas.
• Try walking, biking, or driving new routes with Mozilla Stumbler every day!
• Start with major streets and intersections, then explore smaller streets.
• Your contributions will take a day to show up on the coverage map.


• Please report bugs on GitHub:
• or the #geo IRC channel on

To conserve cellular data usage, the Stumbler's map view only shows high resolution map tiles on Wi-Fi. In the Settings, you can change this to always show the high resolution maps,


• Mozilla Stumbler is open-source software. The code is available on GitHub:

From version Mozilla Stumbler 1.8.8:

v1.8.8 adds a permissions fix that caused crashes in v1.8.7.

The 1.8.7 and 1.8.8 releases are mostly concerned with removing the Firefox Accounts integration and removing the leaderboard.

(Android 4.0+)
Latest: 1.8.8 on February 11, 2019
All versions
Mozilla Stumbler 1.8.8
February 11, 2019


Uploaded:February 11, 2019 at 5:29PM UTC

File size:4.73 MB


Mozilla Stumbler 1.8.7
February 8, 2019


Uploaded:February 8, 2019 at 11:35PM UTC

File size:4.76 MB


Mozilla Stumbler 1.8.5
May 10, 2016


Uploaded:May 10, 2016 at 5:07PM UTC

File size:4.78 MB