Privacy Policy
Last updated: 24 September 2026
The short version. Sudoku Workshop has no account, no advertising and no analytics. Your puzzles, progress and settings are stored on your device and are never sent to the developer. The app does rely on two Google components, handwriting recognition and Google Play Billing, which are described below.
What is stored on your device
The app keeps the following in its private storage, which other apps cannot read:
- Your puzzles: the information needed to recreate each puzzle (a seed, its size, difficulty and variant), the digits and pencil marks you have entered, time played, whether it is finished or starred, and the date for daily puzzles.
- Your settings: theme, input method, highlighting and timer preferences, the daily puzzle difficulty, and whether the daily reminder is on and at what time.
None of this is transmitted by the app. If you have Android backup turned on, Android may include this data in your own Google account backup, which is governed by Google’s Privacy Policy. Uninstalling the app deletes it from your device.
Handwriting recognition
Handwriting input uses Google’s ML Kit Digital Ink Recognition. The first time you use it, the app downloads a recognition model from Google, roughly 20 MB. After that, recognition runs entirely on your device and works offline. The strokes you draw are used only to recognize the digit, are not stored, and are not sent anywhere.
According to Google, ML Kit may contact Google’s servers to receive model updates and fixes, and may send Google limited information about the device, the app and how the recognition feature performs. This does not include your handwriting. Google describes this in its ML Kit data disclosure. If you never switch to handwriting input, the model is never downloaded.
Purchases
The Unlimited subscription and the Lifetime unlock are sold through Google Play Billing. Google handles the payment, and the app never sees or stores your name, email address, payment details or billing address. The app receives only a confirmation from Google Play of which products your Google account owns, which it uses to unlock features. See Google Play’s Terms of Service for how Google handles payment information. You can manage or cancel a subscription in the Google Play Store.
Notifications
The optional daily reminder is scheduled and shown by the app on your device. No server is involved. The app asks for notification permission only when you turn the reminder on, and it uses the RECEIVE_BOOT_COMPLETED permission only to reschedule the reminder after your phone restarts.
Network access
The app has no server of its own and makes no network requests of its own. It needs internet access only for the two Google components above: downloading the handwriting model and communicating with Google Play for purchases. Puzzles, including the daily puzzle, are generated on your device.
Third-party code
The app includes Google ML Kit and Google Play Billing. It contains no advertising, analytics or crash-reporting libraries. If the app crashes, Android may offer to send a report to Google. That is an Android feature you control in your device settings, not something Sudoku Workshop requests.
Children
Sudoku Workshop is a general-audience puzzle game. The developer does not collect personal information from anyone, including children.
Changes
If this policy changes, the new version will be published on this page with a new “last updated” date.
Contact
Questions about this policy can be sent to the developer contact email listed on the app’s Google Play store page.