Privacy Policy
Last updated: January 8, 2026
1. Data we process
1.1. Account and subscription
- Email address β the account identifier
- Password β stored only as an irreversible hash
- Subscription status, payment identifiers and payment history
- The fact and date of consents (policy, personal data processing)
1.2. User content (sync)
When signed in, the server synchronizes between your devices:
- Your own opening courses (title, PGN text, settings)
- Learning progress per line (spaced-repetition state)
- Linked Lichess / Chess.com usernames (to fetch your games)
1.3. Games and AI analysis
- Your game records (PGN) fetched from Lichess / Chess.com
- When you request AI analysis: the game score and engine-computed data (evaluations, lines, move classifications) are sent to the Z.ai service to generate textual comments. No account content is sent.
1.4. Analytics and technical
- Anonymous device identifiers and usage events (AppMetrica)
- Server logs (including IP address) β for diagnostics and security
We do not collect data unrelated to the service. Learning statistics and settings are primarily stored on your device.
2. Purposes
- Registration, sign-in and account recovery
- Providing the subscription and syncing data across devices
- Generating AI game comments upon your request
- Improving the app and diagnosing errors
- Fulfilling the subscription agreement and legal obligations
3. Third parties
- Tochka Bank β payment acquiring. Card details are entered on the bank page and never reach us; we only receive the payment status.
- Z.ai β AI comment generation on request (game data only, no account content).
- AppMetrica β anonymized analytics.
- Lichess / Chess.com β fetching your public games by linked username (read-only).
- Hosting and email providers β as required to run the website and send emails.
Personal data is never sold or shared for marketing. Disclosure is possible only under lawful requests from authorized bodies.
4. Payments
Subscriptions are paid for only on the debutus.ru website; purchases inside the mobile app are not performed and store payments are not used.
- Payments are processed by the acquiring bank (Tochka Bank) on its secure page.
- We only receive the payment status and a subscription identifier.
- Payment records are retained as required by applicable law.
5. Cookies
The website uses a single technical session cookie (httpOnly) to keep you signed in to your account. There are no advertising or tracking cookies.
6. Retention
- Account data and content β until account deletion (available in the app: Settings β Delete account)
- Payment records β as required by law
- Analytics β up to 7 years (AppMetrica policy)
- Service logs β up to 1 year
7. Your rights
- Request information about your data and a copy of it
- Correct or delete data; delete the whole account β from the app
- Withdraw consent to personal data processing (withdrawal = account deletion; the service cannot operate without it)
- Opt out of analytics in device settings
Send requests to dev.epriori@gmail.com β we respond within 30 days.
8. Data protection
- Encryption in transit (HTTPS/TLS)
- Passwords β bcrypt hashing; sessions β signed JWT in httpOnly cookies
- Restricted server access and regular backups
9. Changes
We may update this Policy; the current version is always at debutus.ru/privacy. Material changes are announced in the app.
10. Contact
Operator: Daniil A. Fukalov
Email: dev.epriori@gmail.com