Privacy
Last updated October 2026.
What we collect
When you sign up: your email and a username, plus a password if you create an email account (stored and verified by our authentication provider, Supabase — we never see or store your password in plain text). We recommend “Sign in with Google” instead: with it there is no ProblemLab password at all, so there is nothing of yours to leak if this site is ever compromised. As you use ProblemLab: your goal and target date, your rating, which problems you've attempted, your answers, whether you used a hint, and your streak/XP. If you join a class: which class, when you joined, and your rating at that moment (to show progress since joining). That's it — no payment information is collected, because the product is free.
How we use it
Solely to run the product: calibrating your rating, building your daily plan, and showing your own progress back to you. We don't sell your data, and we don't run third-party advertising or analytics trackers on this site.
Hints
Hints are generated by a fixed, rule-based set of strategies that runs entirely on ProblemLab's own servers. No problem text or account data is sent to any third-party AI provider to produce a hint — nothing about your activity leaves ProblemLab for this feature.
Rankings and classes
On the Leaderboard page you see your own name in full, highlighted; every other name is shown with only its first and last letter, the rest replaced by asterisks, and the other names on it are currently placeholder content, not other students. You can turn off “Show me on the leaderboard” in Settings to keep your XP and streak off the board entirely. If you join a class using a code from a teacher, that teacher can see your rating, accuracy, number of attempts, current streak, and the date you joined — never your email. You can leave a class at any time from Settings, which removes you from that teacher's view immediately. A teacher's own students are visible only to that teacher, never to other students or other teachers.
Cookies
We use one functional cookie set by our authentication provider to keep you signed in. There are no advertising or tracking cookies.
Deleting your data
You can permanently delete your account and every record tied to it — rating, attempts, plans — yourself, at any time, from Settings. This is immediate and cannot be undone.
Questions
Reach us at support@problemlab.net.