Slack | WhatsApp system design - tarunchhabra/parakalo GitHub Wiki

Connection: First a Https call is made and then a long-lived WebSocket connection is established.

Websocket - bidirectional protocol based on TCP.

https://learning.oreilly.com/videos/how-slack-rearchitected/0636920459804/0636920459804-video329997/

Slack loaded data at boot time used to fetch snapshot of your team details such as user, channels etc. This was good for short term. Solution - Lazily load data on demand.