Engineering @ Facebook: Facebook Chat. The new Facebook Chat uses Comet (long polling with a hidden iframe) against a custom web / chat server written in Erlang, designed to handle a launch to all 70 million users at once. It was tested using a “dark launch” period where live pages simulated chat request traffic without showing any visible UI.
Recent articles
- Adding dynamic features to an aggressively cached website - 28th January 2026
- ChatGPT Containers can now run bash, pip/npm install packages, and download files - 26th January 2026
- Wilson Lin on FastRender: a browser built by thousands of parallel agents - 23rd January 2026