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Reconnecting

Welcome Lichess Bots

@thibault Technical

A new way to play chess

Today we're officially introducing a special type of user account: Bots.

Lichess Bots are for:

  • Connected physical boards
  • Vote chess programs (letting spectators vote for the next move to play)
  • Custom online chess clients
  • Chess engines
  • Cyborg/Centaur chess (man and machine teaming up)
  • Anything you can think of that can play chess

Lichess Bots can:

  • Play casual and rated games with other players
  • Send and accept challenges
  • Follow and be followed by other players

Lichess Bots cannot:

  • Participate in tournament or simuls
  • Use lobby seeks or pools
  • Appear in leaderboards

Credit: Matīss Apinis

Who are these bots for?

Engine developers

You can use a lichess bot to try out your engine against actual players, and other engines. If your engine supports the UCI or XBoard protocol, you're in luck! Download the official lichess-bot client and you will be all set in no time.

UI developers

To interface your chess client or physical board with lichess, use the lichess bot HTTP API. Here's a JavaScript reference implementation and the OAuth Personal Token creation page.

Chess players

No need to be a coder to enjoy playing chess with bots! Here's a list of famous bots you can challenge for great chess fun:

More links

Frequently asked questions

  • Can bots play rated games?

Yes. However players only win or lose half rating points during rated games with bots. Cheating in a rated game versus a bot is a bannable offense. If you want to use computer assistance or play Centaur chess, create a Bot account.

  • Why do player ratings even change? Shouldn't the bot rating only be affected?

We don't play casual games the same way we play rated games. In order for the bots to get reliable ratings, we need their opponents to play their best, and that means putting their own rating on the table.

A couple years ago, we tried to give the "Play with the machine" levels actual ratings. It didn't work, because we don't play them seriously, because we don't lose rating to them.

  • Many bots will be strong engines. Won't they disrupt the rating system?

Creating a bot requires technical knowledge and we expect that they will remain a minority. As long as less than 0.1% of new accounts are bots, there won't be any visible change to the rating distribution. We'll keep an eye on it.

  • What about rating manipulation? One could create a bot to farm rating points out of it?

That is called sandbagging or boosting. You can do the same thing with a normal account. Lichess detects it and bans the offenders.

  • Will there be bot contests or tournaments?

Bot play cannot be competitive. No tournaments, no leaderboards, no trophies. Because it all boils down to who's got the biggest CPU to run Stockfish on. Only way we can have competitive engine play is by having lichess host the engines, in TCEC fashion, and we're not going to do that before a long time.