Whetstone Privacy Policy
Effective 8 November 2026 · applies to the Whetstone: Mental Math app for iPhone and iPad
- Data we collect
- Data on your device
- iCloud sync
- The daily reminder
- Purchases
- Permissions
- Diagnostics shared by Apple
- Deleting your data
- Children
- Your rights
- Changes
- Contact
Data we collect
None. Whetstone does not collect any information that identifies you, your device or how you use the app. It contains no analytics, advertising, tracking or crash-reporting libraries, and it makes no network requests of its own. In the App Store's privacy section the app is listed as Data Not Collected.
Data on your device
To work, the app keeps a few things on your device, in its own storage, where other apps cannot read them:
| What | Why |
|---|---|
| Your progress: best stars and times per level, and per day and skill how many problems you solved or missed, how many on the first try, and how long they took | To show your stars, streak, edges and charts, and to choose today's workout |
| Recently missed problem types (for example "division with remainder, level 1-3") | To bring them back in the Daily Workout |
| The level or workout in progress | To continue where you left it |
| Settings: sounds, haptics, reminder time | To remember your choices |
| Whether Whetstone Full was purchased (a copy of what the App Store reports) | To open the right levels when the app starts |
| A random install identifier | To keep each device's progress apart when syncing through iCloud; it contains nothing about you or your device |
This data is included in your device backups, according to your backup settings; the install identifier is excluded from them.
iCloud sync
If you are signed in to iCloud, Whetstone stores your progress in your own iCloud account, using Apple's iCloud key-value storage, so it is the same on your iPhone and iPad. This data is stored by Apple under your Apple Account and is governed by Apple's privacy policy. The developer cannot see or access it. The level in progress and your settings are not synced.
To turn sync off, disable iCloud for Whetstone in your device's iCloud settings. Progress then stays on each device.
The daily reminder
The reminder is off until you turn it on in Settings; only then does the app ask for permission to show notifications. Reminders are scheduled on your device by iOS. No server is involved and nothing is sent anywhere.
Purchases
Whetstone Full is sold by Apple through the App Store. Apple processes the payment; the developer receives no payment details and no information about who you are. The app only asks the App Store whether the purchase was made, so it can unlock the levels. Purchase and refund records are kept by Apple under its privacy policy.
Permissions
Whetstone asks for permission to show notifications only if you turn on the daily reminder. It does not ask for access to your location, contacts, photos, camera, microphone or health data.
Diagnostics shared by Apple
If you choose to share analytics with app developers in your device settings (Settings → Privacy & Security → Analytics & Improvements), Apple may give the developer anonymous crash reports and usage statistics. Apple collects and anonymizes these under its own policy; Whetstone itself sends nothing. You can turn this off at any time in the same settings.
Deleting your data
- Progress: Settings → Delete all progress. This clears it on all your devices.
- Everything on a device: delete the app.
- iCloud: turn off iCloud for Whetstone in your device's iCloud settings. Data in your iCloud account is managed by Apple and can be removed through your Apple Account's iCloud settings.
Children
Whetstone is suitable for all ages and collects no data from anyone, including children under 13.
Your rights
Privacy laws such as the GDPR (European Union, United Kingdom) and the CCPA (California) give you rights to access, correct, delete or port your personal data and to object to its processing. Because the developer collects and holds no personal data about you, there is nothing for us to access, correct, delete or share. The data the app keeps is on your devices and in your iCloud account, where you control it as described above. Whetstone does not sell or share personal data.
Changes
If this policy changes, the new version will be posted on this page with a new effective date. If the app ever starts collecting data, this page and the App Store privacy section will say so before the update is released.
Contact
Questions about this policy: open an issue at github.com/m42cococa/whetstone/issues. Issues are public, so please do not include personal information.