// TOPIC
#websocket
3 articles
◆◆◆AdvancedMetaSnapchat
01Design Nearby Friends (Real-Time Friend Location Sharing)
How to stream real-time friend locations to millions of users without collapsing under the write amplification of a 30× social-graph fanout.
#geo#realtime#pub-sub
24 min◆◆◆AdvancedGoogleMicrosoft
02Design Google Docs (real-time collaborative editor)
Design a real-time collaborative editor like Google Docs: Operational Transformation, the Jupiter model, CRDTs, doc sharding, presence, and offline sync.
#interview#realtime#collaboration
22 min◆◆◆AdvancedMetaDiscord
03Design WhatsApp / Chat System
Realtime 1:1 and group messaging at billions-of-users scale. WebSocket gateways, message store, presence, end-to-end encryption.
#interview#realtime#websocket
18 min