When you scan a sudoku from a photo, the image is decoded and analysed on your device. It is never uploaded, never stored on a server, and never shared with anyone. Recognition uses our own algorithm bundled with the app; no cloud vision service is involved, and the app works with no network connection at all.
The app uses the Android Photo Picker, which means it does not request access to your gallery. The system hands over only the single image you choose. If you take a new photo, it is captured by your device's camera app and passed to us the same way. Once recognition finishes, the image is released from memory and is not kept.
The app embeds three Google services. Data they collect is governed by Google's own privacy policies, linked in section 7.
| Service | What it collects | Why |
|---|---|---|
| Google AdMob | Advertising ID, device and app information, approximate location derived from IP address | To show and measure the optional rewarded video that unlocks an extra scan |
| Firebase Analytics | Anonymous usage events with numeric parameters only: game started and finished, hint used, photo scanned, daily limit reached, ad result, technique practised | To understand which features are used and where people get stuck |
| Firebase Crashlytics | Crash reports and stack traces, device model, operating system version | To find and fix crashes |
Analytics events never contain photographs, file paths, or the contents of your puzzle — only counters such as difficulty level, number of hints, and elapsed seconds.
This app is not directed at children. On Google Play it is listed for an audience of 13 and older. It does not ask for your age or date of birth, and does not store either.
Whoever is using the app, it never grants consent for ad personalisation or for ad-related data storage in Firebase Analytics, does not build advertising audiences, and does not run remarketing lists. In the EEA and the UK, the consent form shown on first launch decides whether the rewarded video you may choose to watch is personalised.
If you believe a child has used the app and you would like the associated analytics or crash records removed, write to the address in section 9.
Name, email address, phone number, contacts, precise location, calendar, files on your device, the contents of the puzzles you solve, and the photographs you scan. The app has no user accounts, so there is nothing to sign in to and nothing tied to your identity.
The app requests internet and network-state access (needed by the ad and analytics services) and the advertising ID permission. It does not request gallery or camera permissions.
Data sent by these services is transmitted over encrypted connections. We do not sell data to third parties.
If this policy changes, the new version is published at this address with an updated effective date. Material changes will also be noted in the app's release notes on Google Play.
Questions about this policy or requests concerning your data: sergeypupochnikov@gmail.com