Privacy

What the extension reads

ChessDummy runs only on chess.com and lichess.org. On those pages it reads the list of moves of the game or analysis that is on screen, so that it can name the opening and check each move against its opening book. It does not read your messages, your password, or anything on other websites.

What it stores

The following is saved in Chrome's storage for the extension, on your own computer:

• Your settings, such as the corner and how the board behaves during a game.
• Your practice list: the opening lines you kept and which ones you marked as known.
• If you enter it, your chess.com or lichess username and a summary of the repeated opening mistakes found in your recent games.

None of this is sent to us. Removing the extension deletes it.

The one optional network request

If you enter a username, ChessDummy downloads your recent public games from the public chess.com or Lichess game API, directly from your browser to that site. Those services receive the request as they would from any visitor and apply their own privacy policies. If you leave the username empty, ChessDummy makes no network requests at all.

What runs on your computer

The opening book and an open-source chess engine (Stockfish) are bundled inside the extension and run locally. Positions are never sent anywhere for analysis.

Permissions

• Read chess.com and lichess.org. Needed to read the move list on those pages and show the corner board.
• Storage. Needed to save your settings and practice list in your browser.
• Offscreen document. Needed to run the bundled engine in the background without slowing down the page.

This website

chessdummy.com is a static site. It sets no cookies and loads no third-party scripts or trackers.

Changes and contact

If a future version changes what is described here, this page will be updated before that version is released. Questions can be sent through the Halfchess support page.