Privacy
Last updated 10 September 2026 · applies to windmillchess.com and the Windmill Android app
Windmill collects nothing about you. There is no account, no sign-up and no analytics. Your games, your engine reports, your training schedule and your settings are stored on your own device and are never sent to us — we have no server that could receive them, because there is nothing to receive them into.
What is stored, and where
Everything the app knows about you lives in your browser's own storage, or inside the app's private storage on your phone:
- Games you import or link, and the engine reports built from them.
- Your drills, repertoire lines and their review schedules.
- Puzzle and bot ratings, goals, and the games you chose to keep.
- Settings: theme, board, engine depth, and the usernames you linked.
None of it leaves the device unless you export it yourself with Back up to a file. Clearing your browser data, or uninstalling the app, deletes all of it permanently — which is why the backup button exists.
What the app talks to
Windmill makes no requests to any server of ours beyond downloading the app itself. It does contact three public chess services, and only for the reasons below. We receive nothing back from them about you.
| Service | When | What is sent |
|---|---|---|
| lichess.org | When you link a lichess username, scout an opponent, open a lichess game link, or look up a cloud evaluation or opening statistics for the position on the board. | The username you typed, or the chess position. Cloud evaluations can be switched off in Settings. |
| tablebase.lichess.ovh | In the endgame trainer, and in positions with seven pieces or fewer. | The chess position. |
| api.chess.com | When you link a chess.com username or scout a chess.com player. | The username you typed. |
Those requests carry no identifier of you beyond what any web request carries. Each service has its own privacy policy, which governs what it does with them: lichess and chess.com.
Usernames you look up are public: the games fetched are the same ones anyone can see on that player's public profile. Nothing private is accessed, and no login to either service is asked for or accepted.
The engine
Stockfish runs on your device, inside the app. Positions you analyse are not uploaded to be analysed elsewhere — the only exception is the optional cloud-evaluation lookup described above, which you can turn off.
Permissions the Android app asks for
- Internet — to fetch your games from lichess or chess.com when you ask it to. The app works offline otherwise.
- Notifications — only if you switch on the daily review reminder. The reminder is scheduled on your phone; no message comes from a server.
- Run after restart — so that reminder survives a reboot.
There is no location, contacts, camera, microphone, storage or advertising-identifier access. The app contains no advertising and no third-party SDKs.
Cookies and tracking
Windmill sets no cookies and embeds no trackers, tag managers, pixels or analytics of any kind. The website's server keeps ordinary access logs with the last part of each IP address removed before it is written; those are used only to count visitors and are not linked to anything else.
Children
Windmill is a chess app suitable for general audiences, but it is not directed at children under 13 and collects no personal information from anyone, of any age.
Your data, your call
Because nothing is collected, there is nothing for us to hand over or delete on request. To remove everything Windmill holds, clear the site's storage in your browser, or uninstall the app. To take it with you instead, use Games → Your data → Back up to a file.
Changes
If this policy changes, the date at the top changes with it. If a future version of Windmill ever collects anything, that will be stated here plainly and before it happens.
Contact
Questions about this policy: hello@zappflux.com.