LLMChess

LLMChess is a browser based chess board for playing against a large language model. The site does not run a model of its own: the player selects a model they already have access to, supplies their own API key, and the page sends each position to that model and plays its reply on the board. The human always plays white. A game is under way once the Start button changes to End, and pressing End or reloading the browser resets the board for a new game. It is a hobbyist and research curiosity rather than a business tool, suited to anyone who wants to see how a particular model reasons about legal moves and positions, or to compare several models on the same task. A log pane with a black border on the right of the board shows the exchange with the model as the game proceeds, which is the most useful part for anyone studying model behavior. The vendor notes the board has been tested in Google Chrome. Alongside the board the site publishes a small set of articles on chess strategy and playing chess online. There is no pricing. The page is free to use, and the only cost is the API usage billed by the model provider whose key is supplied. There is no account, subscription or paid plan, and the site does not store or resell access to any model.