Tag
#realtime
3 articles tagged realtime.
HLDintermediatePremium
Zoom HLD: Why Video Calls Use an SFU, Not a Mesh
A Zoom / video-conferencing system design: mesh vs SFU vs MCU topologies, an SFU that uploads once and fans out, simulcast layer selection, signaling vs media, NAT traversal, and scaling rooms.
14 min read
HLDintermediatePremium
WhatsApp HLD: Real-Time Chat for Billions, Online or Off
A WhatsApp / chat-at-scale system design: persistent connections and a routing registry, store-and-forward for offline users, idempotent ordered delivery, and the delivery-tick receipts.
23 min read
HLDintermediatePremium
HackerRank CodePair HLD: Two People, One File, No Conflicts
A real-time collaborative editor design (CodePair / Google Docs-style): a sequence CRDT with fractional positions, converging concurrent edits over WebSockets, presence, and per-room scaling.
23 min read