Privacy Policy

Last updated: October 2026 · “Wurfel” app

In short: Wurfel runs entirely on your device. There are no accounts, no ads, and no tracking. The camera is used locally only, to read the colors of your cube — no images or cube data are ever sent to us or anyone else. The one thing the app sends on its own is a technical report if it crashes or freezes outright (section 6).

1. Controller

The party responsible for data processing under the General Data Protection Regulation (GDPR) is:

Florian Preusner
Freester Weg 10c
13503 Berlin, Germany
Email: info@wurfel.app

2. Principle: on-device processing

Wurfel is built as a fully offline application. Every function — reading, entering, validating and solving your cube — runs locally on your iPhone or iPad. The app needs no internet connection for its core features and, apart from the crash reports described in section 6, sends nothing to us.

3. Camera access

When you use the scan feature, Wurfel requests permission to access your camera. The camera stream is analysed in real time, on your device, solely to detect the colors of the cube’s faces.

No photos or videos are stored unless you actively choose to save one.
No camera data is uploaded or shared with third parties.
You can revoke the camera permission at any time in your iOS settings. Entering the cube by hand still works without it.

4. No collection of personal data

Wurfel does not collect, store or process any personal data beyond the crash reports described in section 6. There is no registration, no login and no profiles. Your cube inputs and solutions stay local to your device.

5. No tracking, no ads, no analytics

The app contains no advertising, no analytics or tracking services, and no third-party services that profile your behaviour. No advertising identifiers are used. Crash reports (section 6) are not analytics: they contain no usage statistics and are not used to build a picture of how you use the app.

6. Crash reports

If the app crashes or stops responding outright, a technical crash report is sent to us automatically — after a crash, the next time the app starts. We cannot ask beforehand: the part of the app that would ask is what has just stopped. The report is produced by the open-source Sentry library built into the app and delivered to a server we operate ourselves, not to a third party.

A crash report contains:

the technical location of the crash (stack trace) and the app version,
device model, operating system version and the language and region set on the device,
a short log of recent technical events (screens opened, the app going to the background, low-memory and network changes),
a random identifier created by the reporting library on this installation, so that repeated crashes of one installation can be told apart. It is not linked to you, your Apple ID or Google account, and we cannot use it to identify you.

A crash report never contains your cube, camera images, or anything you typed. We use it solely to find and fix the fault, on the basis of our legitimate interest in a working app (Art. 6(1)(f) GDPR), and delete it once the fault is understood.

Other error reports — where the app keeps running but something went wrong — are sent only if you agree. Wurfel then shows you the exact lines that would go, before anything is sent. If you decline, Wurfel does not ask again.

7. App stores

The app is distributed via the Apple App Store and Google Play. When downloading and updating, these providers process data under their own responsibility (e.g. Apple ID, payment and usage data). We have no influence over that processing. The respective provider’s privacy terms apply:

Apple: apple.com/legal/privacy
Google: policies.google.com/privacy

8. Your rights

Apart from the crash reports described in section 6, we hold no data about you to which rights of access, rectification or erasure could apply, and we cannot link a crash report to a person. Regardless, under the GDPR you have the rights to access, rectification, erasure, restriction of processing, data portability and objection. You also have the right to lodge a complaint with a data protection supervisory authority.

9. Changes to this policy

We may update this privacy policy if the app or the legal situation changes. The current version is always available at wurfel.app.

10. Contact

For any privacy questions, reach us at info@wurfel.app.