Privacy Policy
Effective 2026-06-02
Sudokoi is a sudoku app for iPhone and iPad. This policy describes what data the app handles, where it lives, and who it's shared with. Plain language version: we collect almost nothing, your games stay on your device, and we don't track you across the internet.
1. What we collect
1.1 What stays on your device
Sudokoi stores the following information locally on your device, via Apple's SwiftData framework. This data is never transmitted to us or any third party:
- The puzzles you've started or completed and your progress within them.
- Your stats per difficulty (puzzles solved, best times, hint counts).
- Your daily-challenge history and streak.
- Your app preferences (sound, haptics, theme, etc.).
Deleting the app deletes this data. We do not back it up to our servers. iCloud sync may be added in a future version; if it is, this policy will be updated and the data flow disclosed.
1.2 What we receive
The app fetches the day's puzzle from sudokoi.com.
This is a plain HTTPS request for a static file with no user
identifier, no cookies, and no body. Our hosting provider
(Cloudflare) maintains standard CDN access logs that include
IP addresses for a short retention period; we do not analyze
or join these against any other dataset.
If you send us feedback via the in-app "Send Feedback" option (when shipped), the email client on your device will populate a draft with the app version and device model, which you can edit or remove before sending. We see whatever you send.
1.3 Anonymous usage analytics
Sudokoi sends anonymous usage signals via TelemetryDeck, an EU-based analytics service designed for privacy-respecting apps. The signal stream is on by default and you can turn it off at any time via the Help improve Sudokoi toggle under Privacy in the app's Settings. When the toggle is off, the next event simply doesn't send.
When the toggle is on, the app emits short event records such as "a puzzle was started at this difficulty" or "a hint was requested for this technique." TelemetryDeck does not collect your name, email, IP address, device identifier, or any data that could be used to identify you across apps. We use this data only to tune the app's defaults (which features matter to players, which techniques deserve better hints, etc.).
1.4 What we don't collect
- Your name, email address, phone number, or any account.
- Your location, contacts, photos, microphone, or camera.
- Advertising identifiers (we don't show ads).
- Crash logs.
- Anything from third-party tracking SDKs. We don't include any.
2. How we use what we have
The local data described in section 1.1 powers the app itself — your progress, your stats, your settings. It doesn't leave your device.
We don't sell, rent, or trade any data with third parties because we don't have any to share.
3. Subprocessors
The infrastructure Sudokoi depends on:
- Apple — the App Store distributes the app. Their privacy policy applies to your App Store account.
- Cloudflare — hosts the static daily-puzzle JSON files at
sudokoi.com. Their CDN logs include request IP addresses. - TelemetryDeck — receives anonymous usage signals only when you have opted in via Settings (see section 1.3). EU-based; does not collect personally identifying data.
That's the full list.
4. Children's privacy
Sudokoi is rated 4+ on the App Store and is suitable for all ages. We do not knowingly collect data from anyone, including children under 13. If you believe a child has somehow sent us information through this app, please contact us and we'll delete it.
5. Your rights
Because Sudokoi doesn't collect personally identifiable information about you, there is no account to access, export, or delete on our end. The data the app stores on your device is yours; deleting the app removes it.
6. Changes to this policy
If we change this policy, we'll update the effective date at the top of this page. Material changes that affect what data we collect or how we use it will be flagged in the app's release notes.
7. Contact
Privacy questions: feedback@sudokoi.com.