In the World Computer Chess Championships 2004 Crafty won the fourth place with the same number of points as the third place finisher, Fritz 8, despite running on stronger hardware than all other programs. On the November 2007 SSDF ratings list, Crafty was 34th with an estimated ELO rating of 2608.
Crafty is written in ANSI C with assembly language routines available on some CPUs, and is very portable. The source code is available, but the software is for "personal use" only.
Crafty pioneered the use of rotated bitboard data structures to represent the chess board, and was one of the first chess programs to support multiple processors. It also includes negascout search, the killer move heuristic, static exchange evaluation, quiescence search, alpha-beta pruning, a transposition table, a refutation table, an evaluation cache, selective extensions, recursive null-move search, and many other features (cf manual). Special editions of the program include enhanced features such as an opening book, positional learning, and an endgame tablebase.