Privacy

Updated October 20, 2026

Without an account

Progress, your streak, Daily puzzle results and the theme you chose stay in your browser only (localStorage). The site language is remembered in a lang cookie.

With an account

We keep your name, email, a hash of your password (or your Google profile if you sign in with it), plus progress, your streak, Arena duels, coins and skins. The email is for signing in and, when enabled, for password reset and address confirmation mails. No newsletters.

Statistics

We count which pages and features are used ourselves: no third-party trackers and no ads. Events carry no names, emails or answers you typed; your browser gets a random id. Events are deleted after 90 days.

Online lessons

For class lessons we keep the schedule, the topic and the materials. Invites (.ics) are emailed to you when mail is on. When a lesson uses the site's video (Jitsi by 8x8), 8x8 carries the call and tells us when you joined and left: that makes the attendance your teacher sees. Lines you write on a lesson's T-account board are saved with the lesson under your name, and the class sees them.

Lesson recordings

A lesson is recorded only when the teacher turns recording on. Before joining you agree to recording with a separate checkbox that is never ticked for you; without it you still take part but are left out of the recording. Recordings are stored by 8x8; the class's members and teachers see the link.

If you connect the Telegram bot, we keep the chat id and your language to send lesson and due-date reminders, duel invites and marks. /stop in the bot, or Disconnect on the Lessons page, removes the link.

Where data lives

The site runs on Vercel and stores data in a PostgreSQL database; mail goes out through Resend. Data is never sold or shared for advertising.

Deleting

Your profile has a Delete account button: the account and all progress are deleted at once and for good. Browser data goes when you clear the site's data.