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Privacy Policy

Sudoku Showdown · Last updated 22 June 2026

The short version: Sudoku Showdown has no ads, no analytics SDKs, no third-party trackers, and no account sign-up. Single-player works fully offline. The only data that ever leaves your device is the minimum needed to run a multiplayer match, and it isn't tied to your real identity.

1. Who we are

Sudoku Showdown (“the app”) is published by Expresso Codes (“we”, “us”). For any privacy question, contact privacy@expressocodes.xyz.

2. What we do not collect

No name, email address, phone number, or real-world identity.
No advertising identifiers (no IDFA / no Advertising ID). The app contains no ad networks.
No third-party analytics or tracking SDKs.
No contacts, photos, location, microphone, or camera access.
No selling or sharing of data with advertisers or data brokers, ever.

3. Data stored only on your device

The following stays on your device and is never uploaded to us:

Your active and saved games (board state, notes, timer, undo history, mistakes).
Your statistics and records.
App preferences (theme, sound, haptics, difficulty defaults, and the display name you choose).
Your saved friends list, which lives on-device and rides along with your device's own backup.

Deleting the app removes this local data from your device.

4. Data used for multiplayer

Only when you start or join a multiplayer match does the app contact our matchmaking service to relay the game. To do that it sends and stores the minimum needed:

Data	Why
A self-generated display name (e.g. `baller#1234`)	So an opponent can see who they're racing. You pick or regenerate it; it is not your real name.
An anonymous player & routing identifier	A random ID created on first launch so the service can route invites and matches. It is not linked to your Apple/Google account, email, or device identifiers.
Match data: the shared game number, difficulty, and room/invite codes	So both players generate and race the same puzzle.
Your result for a match: elapsed time, hints used, mistakes, completed yes/no	So the service can compare the two finished runs and show who won.

Single-player mode makes no network requests and needs no connection.

5. Where it's processed and how long it's kept

The matchmaking service is operated by us on our own server hosted in the European Union (Contabo, Germany). It is intentionally lightweight: match and queue state is short-lived and used to pair players and compare results, not to build a profile of you. We do not maintain a persistent saved-friends graph on the server.

6. Children's privacy

Sudoku Showdown is suitable for all ages and does not knowingly collect personal information from anyone, including children. Because we collect no personal identity data, the app does not build profiles of users of any age.

7. Your rights (GDPR & similar)

Because the app collects no personal identity data, there is normally nothing personal to export or erase. Local data is removed by deleting the app. If you believe we hold any data relating to you and want it removed, email privacy@expressocodes.xyz and we'll help. Depending on where you live you may have rights to access, correct, or delete data and to lodge a complaint with your local data-protection authority.

8. Security

We keep the data footprint small by design and limit what the service stores. As the app and service mature we are moving all multiplayer traffic to encrypted HTTPS connections.

9. Changes to this policy

If we change what the app collects, we'll update this page and revise the “Last updated” date above. Material changes will be reflected in an app update.

10. Contact

Questions or requests: privacy@expressocodes.xyz.