Privacy
This site has no ads and no tracking cookies. The separate admin panel also uses a Steam sign-in session cookie. It sets cookies only if you sign in with Steam: scw_session keeps you signed in for up to 90 days, and scw_auth lasts ten minutes while Steam confirms who you are.
Visits are counted by Cloudflare Web Analytics, which uses no cookies or fingerprinting and stores no personal data.
The daily game also records a few steps of each visit: the page loading (in rough seconds), the guide offered, opened or skipped, the first move on a board, the first mistake, hints used, and how a board ended (win or loss, roughly how much of it was opened, lamps left). Each step adds one to a counter for that UTC day and is kept with a random ID for that page load and a random token kept in this browser's local storage (scw_device, not a cookie); we store only a keyed hash of the token. The token is not created or sent when Do Not Track or Global Privacy Control is on, and clearing this site's data starts a new one. If you came from another site, only its domain is kept with the visit, never the full address. No IP address or browser details are kept with these steps, and they are not linked to your Steam account. Visits are deleted after 30 days.
If you sign up for the beta, your email address and subscription status are stored in our database, with a copy in our own Google Sheet. Resend sends the beta and Sudochessweeper news. We keep delivery results and do not track opens or clicks.
The feedback form sends your message, any contact you leave, the page's address, your last daily result and the time, but not your name or IP address. Messages are stored in our database for handling by the site owner, with internal status and notes. Earlier messages remain in our Google Sheet and may be copied into the same inbox.
Without signing in, Daily and Endless results and started boards stay on this device, except the last Daily result, sent with your feedback. Guests and each Steam account have separate local saves. Signing in claims unassigned guest play once; switching accounts restores that account's saves.
If you sign in with Steam, we keep your Steam ID, name and avatar (refreshed when you sign in and at most once a day otherwise), your Daily results (day, win or loss, score, size, lives left and board map), and Endless board IDs, results, scores and streak counts. We also keep record times, Daily import source and client version, your profile link and sign-in sessions. Steam never shows us your password or email. Finished results sync with your account; started boards stay on their device.
Your profile page is unlisted: anyone with its link can see it. Its address is a random code, not your Steam ID. Until midnight UTC, today's map is hidden from anyone who is not signed in or has not finished today's daily.
To show which Steam friends play here, we ask Steam for your friends list and keep only those with a profile here. We refresh that list at most once an hour and may show the saved list if Steam doesn't answer. Those friends can see your streak and which dailies you played.
Voting for tomorrow's board needs no sign-in. We keep a keyed hash of your browser's random token, or of your player ID if signed in, to prevent repeat votes. Ballots and size totals are stored separately, with no link showing which size you chose. To limit votes per network, we keep a keyed hash of your IP address, never the address, until voting closes at midnight UTC.
Profile pages load Steam avatars straight from Steam's image servers, so Steam sees that request like any other image load.
You can delete your profile from its page at any time: your account, results, endless boards and sessions are erased and you vanish from your friends' lists, all at once. Hashed ballots and size totals stay. Device saves stay too: reconnecting the same Steam account can upload its retained Daily history again. Previously synced Endless boards stay local and aren't uploaded again, so a recreated profile's Endless totals can differ. There you can also download your profile, Steam identity, Daily results and Endless boards as a JSON file. If you cannot sign in, ask for an export or deletion, or have your address removed, through the feedback form on the home page.
Your manual language choice is kept in browser local storage (scw_site_language) until you change it or clear this site's data. It is not sent to the server.