Privacy Policy

Effective date: July 2, 2026

1. What We Collect

  • Account information. When you sign in with Google, we receive your email address, name, and profile picture. Your email address identifies your account.
  • Learning data. Your study progress: which cards you have reviewed, review scores, scheduling data, and learning streaks.
  • Content you create. Topics, decks, and cards you author in the Service.
  • Code you run. Code submitted to the exercise sandbox is processed to execute it and return results. It is not used for any other purpose.
  • Payment information. Payments are processed by Stripe. We never see or store your card number; we store your Stripe customer ID and subscription status.

2. How We Use It

We use your data to operate the Service: authenticate you, schedule your reviews (spaced repetition requires storing your review history), run your code exercises, manage your subscription, and prevent abuse (rate limiting). We do not sell your personal data, and we do not use it for advertising.

3. Third-Party Services

  • Google — sign-in (authentication only).
  • Stripe — payment processing and subscription billing. See Stripe's privacy policy.

4. Cookies

We use cookies solely to keep you signed in (session cookies). We do not use third-party tracking or advertising cookies.

5. Data Retention and Deletion

We keep your data for as long as your account exists. You can delete your account at any time from your preferences page; this permanently deletes your account, learning progress, and content you created, and cancels any active subscription. Billing records held by Stripe are retained as required for accounting and legal compliance.

6. Security

Data is stored in access-controlled databases, transmitted over HTTPS, and code exercises run in isolated sandboxes. No system is perfectly secure, but we take reasonable measures to protect your data.

7. Your Rights

Depending on where you live, you may have rights to access, correct, export, or delete your personal data. Account deletion is self-service (see above); for other requests, contact us and we will respond within a reasonable time.

8. Changes to This Policy

We may update this policy from time to time. If we make material changes, we will update the effective date above and, where appropriate, notify you in the Service.

9. Contact

Questions about privacy? See also our Terms of Service.