Privacy & AI

Full account: email and optional first name, linked to a persistent login. Quick-access email: name and email, stored for the session only.

Solve history: time taken, hints used, attempts, and lines of code. Linked to your account if logged in, anonymous otherwise.

AI feature: we log your email, the problem you were on, and the type of call. If you're signed in, this is also linked to your account. We do not store your code or the AI's response.

Purchases: if you buy AI credits, Stripe (our payment processor) handles your card details directly, and we never see or store them. We keep a record of what you bought and when, linked to your account.

Email and name: to manage your account and address you by name.

Solve history: to show you your personal stats and calculate anonymous percentile rankings shown to all users after a solve.

AI usage log: to enforce the limit of three free AI calls per person per day, and to track any paid AI credits you've bought and used.

Purchase record: so paid features actually unlock for you, and so we can handle refunds or support questions.

Only you can see your solve history. Aggregate solve data contributes to percentile rankings shown to all users, without your name or email attached.

We do not sell data, share it with third parties, or use it for advertising.

Your data is kept until you delete your account. Deleting is immediate and irreversible. It deletes your login, email, name, AI usage log, tutor access and any tutor access request. It also takes you off every class list and deletes our records of the reminders we sent you and of any emails we couldn't send you.

Some records stay without your name or email, so that figures other people rely on stay correct. Your solve history is kept for percentile rankings. Quiz answers and scores you submitted stay in your tutor's results, under a code in place of your email. An exam you started but didn't submit is deleted and leaves no score. If you are a tutor, the quizzes, classes and problem sets you made stay. Your co-tutors keep those on a course you share, and only a site admin can open the rest. If you were a course's only owner, the tutor who has been on it longest and still has tutor access becomes its owner. If no other tutor on it has tutor access, a site admin gives it a new owner.

Purchase records are kept too, no longer linked to your name or email, because we're required to retain transaction records for accounting purposes. Stripe separately retains its own copy of every payment regardless of what we do on our end.

Bug reports reach us by email. If the email fails, we keep the report on our admin page until it is sent. Deleting your account deletes any kept report you sent while signed in. Reports already in our inbox, and any you sent while signed out, stay; email privacy@mxlabs.io to have them removed.

When you use AI review, your code and the problem's correct answer are sent to Anthropic via their API. Anthropic's privacy policy applies.

Three free calls per day. Provide your email so we can track usage. Use a name and email for session access, or create a full account to save your solve history and see your stats. Signed-in users can also buy additional AI credits, described under "Purchases" above.