What are Chess engines ?

In computer chess, a chess engine is a computer program that analyzes chess or chess variant positions, and generates a move or list of moves that it regards as strongest. A chess engine is usually a back end with a command-line interface with no graphics or windowing. Engines are usually used with a front end, a windowed graphical user interface such as Chessbase or WinBoard that the user can interact with via a keyboard, mouse or touchscreen. This allows the user to play against multiple engines without learning a new user interface for each, and allows different engines to play against each other. Many chess engines are now available for mobile phones and tablets, making them even more accessible.

Types of chess engines

Public unavailable – are chess engines that are not available to the public
Free – are chess engines you can download for free and load into your chess software/GUI
Paid engines – are basically chess software that comes with an engine and a GUI. You can load other free chess engines into your paid chess software.

Chess engines list:

Free chess engines: (Require paid or free GUI)
Stockfish
Komodo
Houdini
Critter
Gull
Rybka
Strelka
Protector
Crafty

Paid chess software:
Shredder
Frtiz
Chessbase

Public unavailable chess engine
Alphazero – is the strongest chess engine at the moment.