Privacy policy
Last updated 12 October 2026
Chess Sensei is a chess training app (game review, puzzles from your own games, opening courses and endgame drills) run by [operator's name] ("we"). This page says what we store about you, why, who else is involved, and what you can do about it. The short version: we keep what you give us to review your games, nothing else; there are no ads, no analytics and no tracking; and you can download or delete everything at any time.
What we store
| What | Why |
|---|---|
| Your email address and, if you set one, a display name | To log you in, and to send the emails you ask for (confirming your address, resetting your password) |
| Your password, only as a one-way scrypt hash | To check it when you log in. We can't see your password |
| The games you add (PGN or FEN), your notes, predicted lines and the moves you'd play instead | That's the service |
| Engine analysis of your games, worked out in your browser | So a game opens instantly next time, and for Practice |
| Your settings, puzzle attempts and review progress | So the app works the same on every device |
| Your opening repertoire, the courses you've started and the lines you've learned, your quiz answers, and the endgame drills you've played | To track your progress and bring back what you missed (spaced repetition) |
| Your experience points (XP) and level | To show your progress |
| Chess.com and Lichess usernames you link | To import your public games from those sites |
| Messages you send with the Feedback button (and your email, only if you tick "you can email me") | To improve the app |
| Counters of recent login and sign-up attempts, keyed by a hash of your email or IP address, deleted within about an hour | To stop password guessing and abuse |
We don't use analytics, advertising or tracking of any kind, and we don't sell or share your data.
Cookies and browser storage
We set one cookie, __Host-pm_session, which keeps you logged in. It's strictly necessary for the service, so no consent banner is needed. The app also keeps a copy of your settings in your browser's local storage, so pages look right before they load; nothing in it is sent anywhere else.
Who else is involved
- Railway (railway.com) hosts the app and its database.
- Resend (resend.com) delivers our emails, so it sees your email address and the email's content.
- Chess.com and Lichess: if you link an account, our server asks them for your public games, sending only your username. If you sign in with Lichess, Lichess tells us your username; we don't keep the access token.
- Stockfish, the chess engine, runs in your own browser: your games aren't sent anywhere to be analyzed. The opening statistics and endgame lessons are built in advance from public data (the Lichess open database and tablebase); using them sends nothing about you to anyone.
How long we keep it
Until you delete it. Deleting a game deletes its notes, analysis and puzzle attempts. Deleting your account deletes everything above at once, except feedback messages, which are kept without anything linking them to you. Our hosting provider keeps server logs (which include IP addresses) for a limited time for security.
Your rights
- Access: Account → "Download my data" gives you everything we store about you, as one file.
- Correction: you can change your name, email and password, and edit or delete any note or game.
- Deletion: Account → "Delete my account" removes it immediately.
- Questions or complaints: email support@thechesssensei.com. If you're in the EU or UK you can also complain to your data protection authority.
Where the law asks for a basis: we process your data to provide the service you signed up for, and, for the attempt counters and security logs, in our legitimate interest in keeping the service safe.
Age
You must be at least 13 to use Chess Sensei, or older where your country requires it (for example 16 in some EU countries).
Security
Everything travels over HTTPS. Passwords are hashed with scrypt, and session and email-link tokens are stored only as hashes. No system is perfectly secure; if something goes wrong we'll tell affected users.
Changes
If this policy changes in a way that matters, we'll say so in the app before it takes effect. Contact: support@thechesssensei.com.