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# Shared Items – February 8, 2010
- URL: https://oroup.com/blog/2010/02/shared-items-february-8-2010/
- Published: 2010-02-08T06:03:37.000Z
- Updated: 2010-02-08T06:03:37.000Z
- Description: How Facebook uses Erlang for real-time chat – Off the Grid!! February 8, 2010 – This is a somewhat old blog post from a Facebook engineer describing how they engineered the chat system in Erlang. It’s notable because it contains…
- Author: Oliver Roup
- Tags: Shared Items, #wp, #wp-post, #Import 2026-07-05 22:27

- [How Facebook uses Erlang for real-time chat – Off the Grid!!](http://gregosuri.com/how-facebook-uses-erlang-for-real-time-chat?ref=oroup.com)
- February 8, 2010 – This is a somewhat old blog post from a Facebook engineer describing how they engineered the chat system in Erlang. It’s notable because it contains a description of a scale testing technique I’ve never heard of before – they did a “dark launch” where real users pages were simulating status update connections and even fake message sending without ever drawing a single element on screen. This seems like a very novel way to get realistic load testing (realistic because it’s real people with real data) but without exposing your users to a system with bugs. Clever!