PyChess is a free, open-source online chess platform whose standout feature is its breadth of chess variants. The server supports over 60 variants including Crazyhouse, Atomic, Chess960, Three-Check, Antichess, Horde, Racing Kings, Shogi, Xiangqi, Makruk, Minishogi, and many more — making it the most comprehensive variant platform available.

Beyond variants, PyChess offers standard chess with rated play, tournaments, and puzzles. The platform runs Fairy-Stockfish for analysis, which handles the variant rule sets that standard Stockfish cannot evaluate. Community tournaments are regularly scheduled for various variant types.

PyChess is entirely free and requires no account to explore. It is the platform of choice for chess variant enthusiasts who want a server dedicated to the breadth of chess-related games rather than just standard chess with occasional variant support.