Privacy
The short version: there is no account, no tracking and nothing to delete on our side, because nothing is sent to us.
What we store
No account. You never sign up, log in or give us your email address.
No tracking cookies. This site does not use cookies for analytics or advertising, and does not load third-party trackers.
Your progress stays in your browser. Completed lessons, exercise results, favourites and review schedules are stored in your browser's localStorage on your own device. We never see this data and cannot recover it for you.
How to keep or delete your data
Go to the progress page. Export progress downloads everything this site has stored as a single JSON file you keep; Import progress reads that file back, which is how you move your progress to another device or browser. Reset progress clears it permanently. You can also clear the site's data at any time through your browser settings.
Because nothing is stored server-side, we cannot back up or recover your progress for you — the export file is your only copy.