ChessDB is a cloud-based chess position database that covers an enormous range of opening and middlegame positions, providing pre-computed engine evaluations for each one. When you query a position, ChessDB returns the top moves with their evaluations, draw rates, and game counts from the underlying dataset — essentially a merged view of engine analysis and practical game statistics.

The database was built by systematically analyzing positions from master games and extending the tree with engine play, resulting in coverage that goes considerably deeper than conventional opening explorers. It integrates directly with several chess tools and GUIs, and the API is freely available for developers.

ChessDB is free to use and the web interface requires no registration. It is particularly useful for correspondence players and opening researchers who need deep engine-backed evaluations beyond what the Lichess or ChessBase opening explorers provide.