Legal
Privacy policy
Draft — pending business details
What we collect
- Guest practice: a random token stored in your browser and, on our servers, only a one-way hash of it plus the answers you submit and their grades.
- Accounts: email address, a hashed password, optional display name and certificate name, timezone, learning preferences you choose, and your learning activity (attempts, hints used, progress, notes, bookmarks).
- Payments: handled by Stripe on its hosted pages. We receive a customer ID, subscription status, amounts, and dates — never your full card number.
- AI tutor (paid): the request you send and the task context needed to answer it, plus usage counts and token totals for limits and costs.
- Product analytics: event counts (for example “exercise submitted”) without names or emails, and aggregate, cookie-free page analytics from Vercel Web Analytics in production.
- Messages you send us through the contact or team forms.
How we use it
To grade your work, save your progress, show your dashboard and review queue, provide paid features, prevent abuse, send account and (only if you opt in) reminder emails, and improve lessons. We don't sell personal information and don't show advertising.
Service providers
Convex (database and backend), Vercel (hosting and analytics), Stripe (payments), Resend (email delivery), and OpenAI (AI tutor, paid users only). They process data on our behalf to run the service.
Leaderboards, certificates, and educators
Leaderboards are off by default and show only a generated pseudonym. Certificate verification pages are off by default; when you turn one on, it shows only the name you chose, course, date, and verification ID. If you join a class, instructors see your lesson and practice progress for that class — not your notes, AI chats, or billing.
Your choices
In Account → Privacy & data you can export your data, reset progress, or delete your account. Email preferences are in Account → Notifications, and every non-essential email has an unsubscribe link. Payment records that must be kept for financial bookkeeping are retained as required.
Children
The service is intended for learners aged 16 and older.
Contact
Use the contact form and choose “Privacy or data request”.