Privacy Policy
Last updated: June 7, 2026
1. Data controller
The data controller is Killian Sonna, reachable at admin@preps64.com.
2. Data we collect
When you create an account: your email address and hashed password (or Google account identifier). When you use the service: your chess usernames (Lichess, Chess.com), the openings and moves you create, and your study activity. When you subscribe: payment is handled entirely by Stripe; we only store your subscription status and Stripe customer ID.
3. How we use your data
Your data is used to operate and improve the service, send transactional emails (email verification, subscription receipts), and provide customer support. We do not sell your data to third parties.
4. Analytics
We use PostHog for product analytics (page views, feature usage). PostHog data is pseudonymous and stored on EU infrastructure. We also use the Meta Pixel to measure ad campaign effectiveness. You can opt out of analytics by contacting us.
5. Third-party services
Stripe (payments), PostHog (analytics), Meta (pixel), Resend (transactional email), Vercel (hosting), Railway (database). Each of these processors has its own privacy policy.
6. Data retention
Your account data is retained as long as your account is active. If you delete your account, your personal data is erased within 30 days, except where retention is required by law (e.g. billing records for 7 years under Belgian law).
7. Your rights (GDPR)
You have the right to access, correct, delete, or export your personal data, and to object to or restrict its processing. To exercise these rights, email admin@preps64.com. You also have the right to lodge a complaint with the Belgian Data Protection Authority (APD — autoriteprotectiondonnees.be).
8. Cookies
We use a session cookie for authentication and PostHog cookies for analytics. No advertising cookies are set by preps64 itself.
9. Contact
Privacy questions: admin@preps64.com