Effective date: 13 July 2026 · Last updated: 9 August 2026
This Privacy Policy explains how Sudoku Academy (“the app”, “we”, “our”) collects, uses, and protects your information when you play. By installing or using the app, you agree to the practices described below.
If you have questions about this policy, contact us at nguyenduyanhuit1989@gmail.com.
1. Information we collect
We do not ask for your real name, phone number, photos, contacts, location, or any other identifying personal information. There is no sign-up, no password and no email address: you never create an account. What is published, and only because a global leaderboard needs it, is the nickname and country you pick yourself — see 2.1. Everything else stays on your device. The data the app handles is described below.
1.1 Data you provide / that stays on your device
- Game progress — Best completion times, difficulty stats, Adventure stars, daily-challenge streak, coin balance, and power-up inventory. Stored locally on your device.
- Purchases — Whether you own “Remove Ads” (so ads stay off). Stored locally and restorable from your store account.
- Settings — Theme, language, sound/haptics, and mistake-mode preferences. Stored locally.
- Display name (required once) — A nickname you set before your first game, shown publicly next to your solve times on the global leaderboard. The prompt starts you off with a randomly suggested name, which you can accept or replace with your own; nothing is published until you save it. Change it any time in Settings → Display name, or remove it entirely with Delete my data.
- Country flag (required once) — A country you pick at the same prompt, shown as a flag on your leaderboard row. The prompt pre-fills it from your device's region setting so you can save in one tap, and you can change it to any country in the list. It is never derived from your IP address or GPS.
- Leaderboard entries — For each difficulty, your fastest solve time and the number of mistakes in that solve, stored with your display name, country and anonymous UID in Cloud Firestore so the global board can be shown to all players. Solves that used a Reveal hint are not submitted.
1.2 Data collected automatically
- Anonymous device identifier — Firebase assigns an anonymous user ID (UID) on first launch. It is not linked to your real identity and is used to tag crash reports and analytics from the same device and, if you set a display name, to own your leaderboard row so you can update or delete it.
- Crash reports (Firebase Crashlytics) — On a crash we collect stack trace, device model, OS version, app version, available memory, and gameplay context (mode, level, score) to diagnose and fix bugs.
- Gameplay analytics (Firebase Analytics) — Anonymous event counts (level started / completed / failed, power-up used, ad watched, purchase made, daily login, screen views), used in aggregate to improve game balance. No personal data is attached — only gameplay/monetization metrics.
- Advertising identifier (AdMob) — Android Advertising ID or iOS IDFA, collected only if you allow ad personalization via the consent prompt (EEA/UK) or the iOS App Tracking Transparency prompt. Decline and ads still show, just not personalized.
- Purchase tokens — When you buy Remove Ads or a tip, Google Play or Apple StoreKit sends a purchase token to verify the transaction. We do not receive or store your card number, billing address, or payment details — those stay with Google/Apple.
1.3 What we never collect
- Real name, email (unless you write to support), phone number, address.
- Contacts, photos, microphone, camera, precise GPS location.
- Health data, financial accounts, biometric data.
- Web browsing history outside the app.
2. Third-party services
Sudoku Academy uses the following services. Each has its own privacy practices — please review their policies for details.
| Service | Provider | Purpose |
|---|---|---|
| Firebase Analytics | Anonymous gameplay metrics | |
| Firebase Crashlytics | Crash diagnostic reports | |
| Firebase Authentication | Anonymous user ID (leaderboard ownership, crash / analytics tagging). No email, no password, no sign-up. | |
| Cloud Firestore | Global leaderboard storage (display name, country, solve time) | |
| Google AdMob | Banner / interstitial / rewarded ads | |
| Google Play Billing | In-app purchases on Android | |
| Apple StoreKit | Apple | In-app purchases on iOS |
Google privacy policy: policies.google.com/privacy · Apple privacy policy: apple.com/legal/privacy
3. How we use your data
- Make the game work — Save progress, fulfill purchases, and send any local reminders you opt into.
- Fix bugs — Crash reports help us resolve crashes.
- Improve gameplay — Aggregate analytics help us tune difficulty, reward economy, and feature priorities.
- Show ads — AdMob serves ads (personalized only with consent, otherwise contextual).
- Show the leaderboard — The nickname and country you chose, together with your fastest time per difficulty, are published on the in-app global board so other players can see them. Delete my data removes them.
- Detect abuse — Anonymous flags prevent claiming the same rewarded-ad reward more than once. Display names are checked against a profanity filter before they can be saved, and implausible solve times are not accepted onto the board.
We do not sell your data, share it with brokers, or use it for profiling outside the game.
4. Your rights and choices
4.1 Delete your data
In the app: Settings → Delete my data erases, in one step, all locally stored progress (best times, Adventure stars, Academy progress, coins, daily streak, statistics) and every leaderboard row tied to your anonymous UID, and then deletes the anonymous account itself. This cannot be undone. Purchases are deliberately left untouched, since removing them would take away something you paid for — use Restore Purchases if you reinstall.
By uninstalling: Removing the app clears all local data. Note that uninstalling alone does not remove a leaderboard row you have published — use Delete my data first if you want your name off the public board.
Anonymous diagnostics (on Google servers): Crash reports and analytics are tied only to an anonymous Firebase UID, never to your identity. To request removal of historical crash/analytics data tied to your device, email nguyenduyanhuit1989@gmail.com with your approximate first-launch date; we action it within 30 days.
In-app purchases are tied to your Apple ID / Google account, not our servers — they remain restorable after re-install.
4.2 Opt out of personalized ads
- EEA / UK / Switzerland: Settings → “Manage ad preferences” (appears automatically per Google UMP) → toggle off personalized ads.
- iOS (any region): System Settings → Privacy & Security → Tracking → Sudoku Academy → toggle off.
- Android (any region): System Settings → Google → Ads → “Opt out of Ads Personalization”.
4.3 Opt out of analytics & crash reporting
We do not provide an in-app toggle in non-EEA regions because the data is anonymous and aggregated. EEA/UK users can decline via the first-launch consent prompt. To request removal of historical crash reports tied to your anonymous UID, email support with your approximate first-launch date.
4.4 GDPR rights (EEA / UK users)
You have the right to access the data we hold (anonymous UID + diagnostics), request erasure (see 4.1, answered within 30 days per GDPR Art. 17), object to processing for marketing/analytics (revoke consent via Settings → Manage ad preferences), and lodge a complaint with your local data protection authority.
4.5 CCPA rights (California users)
You have the right to know the categories of personal data collected (see Section 2), the right to delete (see 4.1), and the right not to be discriminated against for exercising these rights. We do not sell personal information.
4.6 Vietnamese users (Decree 13/2023/NĐ-CP)
For users in Vietnam, the same rights apply under Vietnam’s Personal Data Protection Decree (PDPD). Contact support to exercise your rights.
5. Notifications
The app may send local reminder notifications (e.g., a daily-challenge reminder) only if you grant notification permission. These are local — they fire from your device, not our servers, and no data is sent to schedule them. Disable them anytime in iOS Settings → Notifications → Sudoku Academy, or on Android in System Settings → Apps → Sudoku Academy → Notifications.
6. Children’s privacy
Sudoku Academy is not directed at children under 13 (or the equivalent minimum age in your jurisdiction — 16 in most EEA countries). We do not knowingly collect personal data from children. If you are a parent and believe your child has provided data, contact support and we will delete it. The app is rated Everyone / 4+ and intended for casual puzzle players of any adult age; children may play under parental supervision.
7. Security
- Network traffic between the app and Google/Apple services is HTTPS-encrypted.
- Crash reports are processed by Firebase Crashlytics under their security standards (ISO 27001 / SOC 2 / SOC 3).
- Local game progress is stored in your device’s app sandbox, inaccessible to other apps.
No system is 100% secure. We follow industry-standard practices but cannot guarantee absolute security.
8. Data retention
- Local data — stays on your device until you delete it with Settings → Delete my data or uninstall the app.
- Leaderboard row — kept until you remove it with Settings → Delete my data. Uninstalling alone does not remove it (see 4.1).
- Crash reports — retained 90 days then aggregated.
- Analytics events — retained 14 months (Firebase default).
- Purchase receipts — retained as required by Google/Apple for refund processing.
9. Changes to this policy
We may update this Privacy Policy from time to time. Any change is posted on this page with a new “Last updated” date, so please check back here. Continued use after the change becomes effective constitutes acceptance.
10. Contact
Email: nguyenduyanhuit1989@gmail.com
Subject line tip: include “Privacy” or “GDPR” so we route it correctly.
This policy was prepared for compliance with Apple App Store §5.1, Google Play Data Safety, GDPR (EU Regulation 2016/679), UK Data Protection Act 2018, CCPA, and Vietnam PDPD Decree 13/2023/NĐ-CP.