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# Facebook chat is developed in Erlang
- URL: https://www.process-one.net/blog/facebook-chat-is-developed-in-erlang/
- Published: 2008-05-17T22:00:00.000Z
- Updated: 2024-09-24T14:02:55.000Z
- Description: Facebook recently announced that their chat system is based on Erlang code running on a large cluster. It confirms that Erlang is a key tool for building large scale applications, especially for social networks.
- Author: Mickaël Rémond

Like ProcessOne has used Erlang to build its Instant Messaging suite of tools, Facebook is using [Erlang](https://www.erlang.org/?ref=process-one.net) to build its web based chat infrastructure.

The system uses a [Comet based programming](https://en.wikipedia.org/wiki/Comet%5F%28programming%29?ref=process-one.net) approach. From our knowledge the system uses [Mochiweb](https://code.google.com/p/mochiweb/?ref=process-one.net) as its web server to handle the massive number of long polling connections.

[More details are available from Facebook engineering blog](https://www.facebook.com/notes.php?id=9445547199).