Sudoku Dark — Last updated: March 5, 2026
Summary: Sudoku Dark is an offline-first game. You can play without creating an account and all gameplay data is stored locally on your device. If you choose to sign in, certain data is synced to our cloud service to enable cross-device play, leaderboards, and social features. We never sell your data, and we do not show ads.
This Privacy Policy describes how Sudoku Dark ("we", "our", or "the app") handles information when you use our mobile application and web app. We are committed to protecting your privacy and being transparent about our data practices.
Sudoku Dark is developed and maintained by Carlos Codes. This policy applies to all versions of the app distributed through Google Play, the Apple App Store, and the web at sudoku-dark.carloscodesfor.me.
The data we process depends on whether you use the app as a guest or sign in with an account.
When you play without signing in, no personal data is collected or transmitted. All gameplay data is stored exclusively on your device. The app does not require an internet connection to function in this mode.
If you choose to create an account or sign in (via Google or Apple), the following data is collected and stored on our cloud servers to provide cross-device sync, leaderboards, and social features:
| Data Type | Purpose | Required? |
|---|---|---|
| Account identifier | Authenticate your session and link your data across devices | Automatic on sign-in |
| Display name | Shown on leaderboards and to friends | Optional |
| Profile avatar | Shown on your profile and leaderboards | Optional |
| Game results & scores | Populate leaderboards and cross-device history | Automatic on sign-in |
| Statistics | Sync performance data (games played, win rate, best times, streaks) across devices | Automatic on sign-in |
| Achievement progress | Back up and restore your unlocked achievements across devices | Automatic on sign-in |
| Friends list | Manage your friend connections and enable friend challenges | User-initiated only |
We do not collect your email address, phone number, precise location, contacts, or any data unrelated to in-game functionality.
Regardless of whether you are signed in, the app stores the following data on your device using local storage. This data is always available offline and is the primary copy of your game data.
| Data Type | Purpose |
|---|---|
| Game state | Save and resume your current puzzle (board, notes, score, difficulty) |
| Statistics | Track your personal performance (games played, win rate, best times) |
| Streak data | Maintain your daily play streak and streak-freeze count |
| Game history | Record of your recent completed games for review |
| Preferences | Your chosen settings (sound, haptics, theme, display options) |
| Achievement progress | Track unlocked achievements and progress toward goals |
You can delete all locally stored data at any time by clearing the app's data through your device settings or by uninstalling the app.
We use the data described above solely to:
We do not use your data for advertising, marketing, profiling, or any purpose unrelated to app functionality.
We do not sell, rent, or trade any user data with third parties.
If you sign in, certain data is visible to other signed-in users as part of the app's features:
We may disclose data if required by law, court order, or governmental authority.
If you sign in, your data is stored and processed using Appwrite, an open-source backend-as-a-service. Appwrite processes data on our behalf and does not use your data for its own purposes. All data transmitted between the app and Appwrite is encrypted via HTTPS/TLS.
If you choose to sign in with Google or Apple, the respective provider's OAuth service is used to verify your identity. We receive only the minimum information needed to establish your account (a unique identifier and, if provided, your chosen display name). We do not receive or store your password. Each provider's own privacy policy governs how they handle your sign-in data:
Sudoku Dark does not integrate:
The app may send local notifications (e.g., streak reminders) if you grant notification permission. These notifications are generated entirely on your device and do not involve any push notification server, token, or external service. No notification data is transmitted off your device.
Sudoku Dark does not knowingly collect personal information from children under the age of 13 (or the applicable age of digital consent in your jurisdiction). The app does not contain ads and does not engage in behavioural profiling. If you believe a child has provided us with personal data through account creation, please contact us and we will promptly delete it.
We take reasonable measures to protect your data:
No system is 100% secure. While we strive to protect your data, we cannot guarantee absolute security.
Data stored on your device persists as long as the app is installed. You may delete it at any time by:
If you have a signed-in account, your cloud data is retained as long as your account exists. You may request full deletion of your cloud data and account at any time by contacting us at the email address below. Upon receiving a verified deletion request, we will permanently remove all your cloud-stored data within 30 days.
Deleting the app from your device does not automatically delete your cloud account or cloud-stored data. You must request account deletion separately.
Depending on your jurisdiction, you may have the following rights regarding your personal data:
To exercise any of these rights, contact us at the email address listed below.
In compliance with Google Play's User Data policy, we disclose the following:
| Declaration | Details |
|---|---|
| Data collected | Account identifier and display name (only if the user signs in); game activity (scores, stats, achievements) synced to cloud when signed in |
| Data shared with third parties | None — we do not share data with third parties for advertising, analytics, or any other purpose |
| Data encrypted in transit | Yes — all cloud communication uses HTTPS/TLS |
| Deletion mechanism | Users can clear local data via device settings; cloud data deletion available upon request via email |
| Advertising or marketing | Data is not used for ads, marketing, or profiling |
| App functionality | Collected data is used exclusively for core game features (cross-device sync, leaderboards, social) |
We may update this Privacy Policy from time to time. If we make material changes, we will update the "Last updated" date at the top of this page and, where appropriate, notify you within the app. We encourage you to review this policy periodically. Continued use of the app after any changes constitutes acceptance of the revised policy.
If you have any questions, concerns, or requests regarding this Privacy Policy or your data, please contact us at:
Email: carlos@carloscodesfor.me
Website: carloscodesfor.me