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
- GPT-5: Key characteristics, pricing and model card - 7th August 2025
- OpenAI's new open weight (Apache 2) models are really good - 5th August 2025
- ChatGPT agent's user-agent - 4th August 2025