And has an interesting tech-stack.

Edit: Links.

1. https://lichess.org/source

2. https://github.com/ornicar/lila

Indeed. It really made my day when I discovered that Lichess uses an open source library that I made (Snabbdom).

Link please? I mean, to something explaining what is interesting and how is it used. I can find the repo on my own but it's not immediately insightful

From https://lichess.org/source

> Lichess is written in Scala 2.13, 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 prismic.io. 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.

the UX with puzzles on chess.com is much better. The analysis after the game is also pretty cool. It did help me become better. (I'm a super noob) I would happily use lichess but there's a lack of feedback after games there (IMO)