Fruit is a chess engine developed by Fabien Letouzey. In the SSDF rating list released on November 24, 2006, Fruit version 2.2.1 had a rating of 2842. In the CEGT rating list released on January 24, 2007, Fruit version 2.2.1 had a rating of 2776.

At the World Computer Chess Championship in Reykjavík in 2005, Fruit 2.2 scored 8.5 out of 11, finishing in second place behind Zappa.

Until Version 2.1 (Peach), Fruit was free and open-source software subject to the requirements of the GNU General Public License and as such contributed much to the development in computer chess in recent years. Some people still work on the v2.1 source code and have created variations from the original Fruit.

As of July 23, 2007, Fruit became freeware. Fruit 2.3.1 was one of the top 3 free UCI chess engines.

Fruit uses the classical Negascout (principal variation search) algorithm with iterative deepening to traverse the game tree. It also uses the null-move heuristic. The original version used a simplistic evaluation function with a robust search. Later versions have improved evaluation functions. The board representation is distinct — Fruit uses a 16x16 board.

Although in 2007 Fabien Letouzey stopped the development of Fruit with version 2.3.1, the earlier open source 2.1 version provided the basis for many other programs.

Toga II is a derivative created by Thomas Gaksch, currently continued by Jerry Donald Watson. It has more chess knowledge, multi-processor support, and perhaps a better search algorithm. It is based on Fruit 2.1 and is free. The strongest version is Toga II 4.0, released on 29 December 2017 by Jerry Donald Watson. Experimental versions of Toga II running on computer clusters have competed in the World Computer Chess Championship (WCCC). At about 80 ELO above Fruit 2.3.1, Toga II is the strongest Fruit derivative as of March 2014^[update].

In 2008, forks of Toga II started to appear, like Grapefruit and Cyclone.