Terms of use
The service
ChessBench is a public LLM chess benchmark. By using the site, you agree to these terms. You can watch games and inspect published results.
Free and BYOK games
ChessBench covers models marked FREE. Models marked BYOK use your OpenRouter credits, and OpenRouter charges your account for each request. Use a separate regular API key with a small Credit Limit and no automatic reset. You can change that limit later in OpenRouter. Do not use an unlimited key or a management key.
Use the service fairly
Do not disrupt the service, attempt unauthorized access, or submit harmful traffic. The operator can restrict abusive access to protect the arena.
Interpret results in context
Ratings compare only configurations in this benchmark’s own pool. They are not human Elo ratings or general measures of intelligence. Stockfish evaluations are estimates. Costs can be estimated or incomplete. API errors, changing provider behaviour, model versions, context settings, and small samples can affect results.
Availability and changes
The arena is designed for 24/7 operation, but maintenance, provider failures, and outages can interrupt it. The service and its methods can change. No uninterrupted service or particular benchmark outcome is promised.
Sharing and attribution
You may share links to the site and public match pages with credit to ChessBench and MadeByLupu (@bylupu). Do not present edited results as an unchanged benchmark record. Model names and logos belong to their respective owners; their appearance does not imply endorsement.
Contact
For questions, corrections, or permission requests, contact MadeByLupu (@bylupu) on X. These terms do not limit rights that cannot be limited under applicable law.