Last updated: October 22, 2026
We only collect what is needed to run your learning: your account, your progress and your submissions. This page explains what we store and why.
1. What we store
Account details: name, email, hashed password and the interface language you choose.
Learning data: enrolled courses, completed lessons, SQL submissions, grading results, XP and day streak.
2. Cookies
We use two httpOnly cookies to keep you signed in: a short-lived access token and a long-lived refresh token. They are not used for advertising and are not shared with third parties.
You can sign out at any time; the refresh token is revoked on the server immediately.
3. How we use it
Data is used to show progress, compute XP and ranks, grade submissions and answer your support requests. We do not sell personal data.
4. Retention
Account data and learning results are kept while your account is active. When you ask us to delete your account we remove or anonymise personal data within 30 days, except what we must keep to comply with the law.
5. Your rights
You can ask to access, correct or delete your data, and withdraw consent by stopping use of the service. Send requests to hello@datahoc.dev.
6. Security
Passwords are hashed with bcrypt, tokens are stored hashed and sent over HTTPS in production. Even so, no system is perfectly safe — use a password unique to DataHọc.