Lichess is a free and open-source Internet chess server run by a non-profit organization of the same name. Users of the site can play online chess anonymously and optionally register an account to play rated games. Lichess is ad-free and all the features are available for free, as the site is funded by donations from patrons. Features include chess puzzles, computer analysis, tournaments and chess variants. Built for the love of chess, this app is open source and free for all.