Lichess

Lichess is the most complete chess experience, with a simple interface that focuses on the game, a massive array of game related tools and a huge, worldwide community.

The Lichess covenant:

• lichess.org will always be free.
• lichess.org will never contain advertisements.
• lichess.org will always be open source.

FEATURES

• Two-player games between humans
• Single-player games (versus Stockfish, the most powerful open-source engine)
• Spectator mode
• Premoves
• Support for moretime
• Resignation and draw offers
• Ability to abort uninitiated games
• Ability to force resignation
• 'Arena' style tournament feature

Customization

• Time controls for chess clocks, including Fischer delay
• Optional Black and White player randomization
• Ability to request a player to take back a move
• Support for variants: Chess960, King of the Hill, Three-check Chess, Atomic chess, Antichess, Horde chess
• User-defined restriction of who can join games, based on player rating
• Board editor to set up and practice positions against players or people.

Learning

• Opening puzzles to learn good continuations
• Tactics puzzles
• Coordinate trainer to train the locating of chess squares
• Curated library of publicly available chess videos
• PGN import and ability to load positions from FEN

Technology

• Mobile app for iOS and Android
• Works in any modern web browser (except Internet Explorer 8 and lesser versions), with no plugins such as Flash or Java needed
• Availability in over 80 languages
• Ability to toggle the overall theme of the website between black and white
• Basic chess set and background theme switching
• Ability to invite friends to a game via unique links created for every game
• Optional username and password registration
• Option for users to close their accounts