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Thibault Duplessis 6592a2bee3
Merge pull request #12007 from scala-steward/update/sbt-bloop-1.5.6
8 hours ago
.github try node 19 in github assets action 2 weeks ago
app simplify logger configurator 14 hours ago
bin opaque type I18nKey 1 week ago
conf is now the entry point 14 hours ago
modules ignore `pairMeAsap` in tournament join API, when the player already has a game 22 hours ago
project Update sbt-bloop to 1.5.6 10 hours ago
public add disguised pieces as symlinks 1 month ago
translation New Crowdin updates (#11988) 3 days ago
ui yarn run format 21 hours ago
.browserslistrc relocate browsers list 4 years ago
.eslintrc.json remove duplicate extends option 10 months ago
.git-blame-ignore-revs Add 'Reformat with scalafmt 3.6.1' to .git-blame-ignore-revs 1 month ago
.gitattributes Add .gitattributes 7 months ago
.gitignore ui/bleep 2 months ago
.gitmodules install jquery-bar-rating from npm (#6323) 3 years ago
.ignore don't ignore translation sources 2 years ago
.prettierignore yarn run format 6 months ago
.prettierrc.json prettier: mirror chessground scripts and more excludes 2 years ago
.sbtopts.default need more stack space to compile 3 years ago
.scalafmt.conf reorder template imports, disable scalamft import sort 4 weeks ago Fix typos/grammer in contributing 3 months ago Add disguised piece set 1 month ago Update 1 year ago
LICENSE update some old links 2 years ago Readme: Scala 3 2 weeks ago
build.sbt fix build 14 hours ago
crowdin.yml Update Crowdin configuration file 3 years ago
lila Fix logo rendering in bash 3 years ago
package.json Node 19 is now supported (#11932) 2 weeks ago
yarn.lock upgrade ui deps 6 days ago

Build server Build assets Crowdin Twitter

Lichess homepage

Lila (li[chess in sca]la) is a free online chess game server focused on realtime gameplay and ease of use.

It features a search engine, computer analysis distributed with fishnet, tournaments, simuls, forums, teams, tactic trainer, a mobile app, and a shared analysis board. The UI is available in more than 130 languages thanks to the community.

Lichess is written in Scala 3, and relies on the Play 2.8 framework. scalatags is used for templating. Pure chess logic is contained in the scalachess submodule. The server is fully asynchronous, making heavy use of Scala Futures and Akka streams. WebSocket connections are handled by a separate server that communicates using redis. Lichess talks to Stockfish deployed in an AI cluster of donated servers. It uses MongoDB to store more than 1.7 billion games, which are indexed by elasticsearch. HTTP requests and WebSocket connections can be proxied by nginx. The web client is written in TypeScript and snabbdom, using Sass to generate CSS. The blog uses a free open content plan from All rated games are published in a free PGN database. Browser testing done with Browserstack. Proxy detection done with IP2Proxy database. Please help us translate Lichess with Crowdin.

See for a list of repositories.

Join us on Discord for more info. Use GitHub issues for bug reports and feature requests.


./lila # thin wrapper around sbt

The Wiki describes how to setup a development environment.


Feel free to use the Lichess API in your applications and websites.

Supported browsers

Name Version Notes
Chromium / Chrome last 10 Full support
Firefox 63+ Full support (fastest local analysis since FF 79)
Edge 91+ Full support (reasonable support for 17+)
Opera 55+ Reasonable support
Safari 11.1+ Reasonable support

Older browsers (including any version of Internet Explorer) will not work. For your own sake, please upgrade. Security and performance, think about it!


Lila is licensed under the GNU Affero General Public License 3 or any later version at your choice with an exception for Highcharts. See copying for details.

Production architecture (as of July 2022)

Lichess production server architecture diagram


See and the contributors here:

GitHub contributors

Competence development program

Lichess would like to support its contributors in their competence development by covering costs of relevant training materials and activities. This is a small way to further empower contributors who have given their time to Lichess and to enable or improve additional contributions to Lichess in the future. For more information, including how to apply, check Competence Development for Lichess contributors.