The short version: we do not have accounts, we do not track you, and we keep as little of your game data on our server as we can. There is very little to disclose, by design.
When you submit a PGN for analysis, the game and its move-by-move Stockfish evaluation pass through our server only transiently, for the duration of the analysis itself. Once your browser receives the finished analysis, it saves the full result in your own browser (via IndexedDB) and we delete our copy immediately, so the game is stored only in your browser after that point. As a safety net in case that handoff fails, any leftover analysis record is automatically deleted after 30 minutes regardless.
Games you play against the computer are different: because the engine is an opponent running on our server, the in-progress game (moves, position, result) is kept there so both you and the engine can keep playing it, and so you can return to it later using its own private, unguessable link.
Your username is not stored on our server at all. It is kept only in your own browser (local storage) and is used solely to pre-fill the form and highlight which side is yours in the replay.
We do not require or collect accounts, email addresses, or any other identifying information to use the app.
Like all web servers, ours records standard access logs that include your IP address, the pages you requested, and timestamps. These logs are used solely for security and operational purposes (detecting abuse, diagnosing errors). Logs are kept only as long as they are useful and then deleted.
There are no logins, usernames, passwords, or user profiles. We do not ask who you are and we have no way to connect your games to any identity.
The one exception is the optional Chess Coins mode. If you choose to play for coins, you claim a lightweight handle and a PIN so your play-money balance can persist between visits. This is opt-in and used only for Chess Coins; the rest of the app stays fully anonymous. Chess Coins have no monetary value, cannot be purchased, and cannot be redeemed for anything: they are for bragging rights only.
Chess App does not use tracking pixels, advertising networks, or third-party analytics services. Only the essential cookies needed for the app to function (CSRF protection and the Rails session cookie) are used. No data is sent to Google, Meta, or any other third-party service.
You can delete any analyzed game at any time from the library page, which permanently removes it from your browser (there is no server copy to delete). Computer games can be resigned or abandoned; deleting one also removes it from our server. You can back up or move your analyzed game library using the Export and Import feature on the main page.
We do not sell, rent, or share user data with third parties. There is essentially no user data to share: we do not collect it in the first place.
Chess App is built, owned, and operated by Nuthatch, LLC. For questions about privacy, contact us at [email protected].
This policy may be updated from time to time. When it changes, we will update the effective date below. Continued use of the app after a change constitutes acceptance of the updated policy.
Effective date: July 1, 2026