Seconding this! Lichess is also free/libre and open-source[0], and has a really nice API[1] allowing you to do pretty much anything you could think of wanting t

Seconding this! Lichess is also free/libre and open-source[0], and has a really nice API[1] allowing you to do pretty much anything you could think of wanting to do when it comes to online chess. [0]: https://github.com/ornicar/lila/ https://github.com/ornicar/lila/ [1]: https://lichess.org/api https://lichess.org/api