sudoku.day

Data retention

Account data

Your email, display name, solve history, and saved games are kept while your account exists. Deleting your account removes all of them.

Sessions and sign-in links

Sign-in links expire after 15 minutes and are single-use. Sessions expire after 30 days of inactivity. Only hashes of these tokens are stored.

Consent log

Consent decisions are kept as an append-only log (decision, policy version, requesting IP address, timestamp) so we can prove what you agreed to and when. Revoking a consent adds a new entry rather than erasing the old one.

Email delivery records

A log of outbound email sends (address and timestamp, no content) is kept for 30 days to enforce sending limits. Addresses that hard-bounce or report spam stay on a do-not-send list until removed; that list exists precisely so we never email those addresses again.

Device data

Local-storage data on your device (games, history, settings) is yours. Clearing your browser storage removes it.