Privacy policy of the “RudelRally” app

Last updated: 15 November 2026 · applies to the Android app RudelRally (de.christiankempf.rudelrally). The website is covered by the general privacy policy. In case of doubt the German version prevails.

In short: RudelRally measures by GPS, OBD-II adapter or wheel sensor and stores vehicles, calibration runs, rallies and orienteering tasks only on your phone. From the internet the app loads map tiles and road data. Follow-me runs encrypted via your own OneDrive. There is no account with me, no server and no advertising.

1. Controller

2. Location

RudelRally uses your phone’s GPS to determine distance, speed and the exact time. This only happens while an average, the tripmaster or a recording is running – then also in the background, indicated by a persistent notification. Measuring does not start by itself when the phone restarts. Positions are processed and stored on the device; they are only passed on if you switch on follow-me (see 6).

3. What the app stores

• Vehicles and calibration runs: name of the vehicle, the assigned measuring device (OBD adapter or wheel sensor), measured and specified distances, factors calculated from them.
• Averages, tripmaster and time: target values, intermediate readings, corrections, time controls and countdowns.
• Rallies: the recorded positions per stage, imported GPX tracks and orienteering tasks with their sketches.
• Settings: such as tolerance, signal tones and competition mode.

4. Map and road data

For the map RudelRally loads vector tiles from OpenFreeMap (openfreemap.org, map data © OpenStreetMap contributors). For the orienteering solver, measuring along the road and the notice of fixed speed cameras the app requests the surrounding road network from an Overpass service for OpenStreetMap data: first from overpass-api.de (FOSSGIS e. V.) and, if it is busy, from the mirror overpass.private.coffee (Austria). The app stores the loaded road network on the device. In each case only the requested map area and, for technical reasons, your IP address are transmitted – no identifier, no recordings and not your position. In competition mode the map is not shown. The legal basis is Art. 6(1)(b) GDPR.

5. OBD-II adapter and wheel sensor

If you choose an OBD-II adapter or the RudelRad wheel sensor for a vehicle, RudelRally finds and connects it via Bluetooth. The same applies to the RudelRallyDisplay: it only receives the values you choose to show (such as deviation, trip, target average, gear, countdown), no positions, and sends button presses back. From the vehicle the app only reads the speed and – on supported vehicles – the odometer. The data stays on the device; only the adapter’s name and address are stored so it can be found again next time.

6. Follow-me via your OneDrive

If you switch on follow-me, RudelRally creates a folder “RudelRally” in your OneDrive and writes your latest position and the track driven there about once a minute – end-to-end encrypted (XChaCha20-Poly1305). The key is contained only in the invitation (RALLY1-…) that you send to your family yourself; whoever has it can see where you are. Viewers read the folder via a sharing link. For this you sign in with your Microsoft account (login.microsoftonline.com); the files run via the Microsoft Graph interface (graph.microsoft.com). The provider is Microsoft Ireland Operations Limited, One Microsoft Place, South County Business Park, Leopardstown, Dublin 18, Ireland; Microsoft’s privacy statement applies. Microsoft only sees encrypted files and the technical details that come with any storage. The sign-in tokens are stored encrypted in the Android Keystore. Follow-me can be switched off at any time; in competition mode it is locked. The legal basis is Art. 6(1)(a) and (b) GDPR.

7. Orienteering assistant (optional, only with your own key)

The orienteering assistant and reading sketches and regularity test tables from a photo are only visible if you enter your own API key from Anthropic in the settings. Then the photos and messages you send there go to the Claude interface of Anthropic, PBC (USA, api.anthropic.com); the assistant looks up place names and junctions at Nominatim (nominatim.openstreetmap.org, OpenStreetMap Foundation, United Kingdom). Your contract with Anthropic and its privacy policy apply. The key is stored encrypted in the Android Keystore. Without a key none of these transfers take place; in competition mode the assistant is locked. The legal basis is Art. 6(1)(a) GDPR.

8. Import and export

You can pass on a rally or stage as a GPX file via Android’s share function, and an orienteering task as well. Where it goes is up to you. GPX files you pick via the file picker are read in by the app.

9. Watch app

If you use RudelRally on a Wear OS watch, phone and watch exchange the display state and button presses via the Wearable interface of Google Play services, usually directly via Bluetooth. Only values such as deviation, task time and countdowns are transmitted, no positions.

10. Permissions

11. No advertising, no analytics

RudelRally contains no advertising, no analytics tools, no trackers and no crash reporting.

12. Retention and deletion

The data stays on your device until you delete it in the app or uninstall the app. You delete the follow-me folder in OneDrive there yourself. Android may include app data in your personal device backup if you have enabled this in the system settings.

13. Your rights

As I receive no data from the app, I cannot provide information about it or delete it; you are in control – on your device and in your OneDrive. For questions, contact me at the address above. You may also lodge a complaint with a data protection supervisory authority, for example the one responsible for me: the State Commissioner for Data Protection and Freedom of Information Baden-Württemberg, Lautenschlagerstraße 20, 70173 Stuttgart, Germany.