Practice · High Level Design · Real-Time and Location
Design a Chat App
IntermediateWebSocketsMessage storeDelivery receiptsPresence⏱ 3-4 h
WhatsApp-style chat for millions: persistent connections, storing and delivering messages, the sent / delivered / read ticks, online presence, and group chats.
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The full solution is on its way. Here is its outline, so you can try designing it yourself first.
- 01Problem introduction
- 02Problem statement
- 03Requirements
- 04Capacity estimation
- 05API design
- 06Database design
- 07Architecture
- 08Request lifecycle
- 09Component deep dive
- 10Scaling, 100 to 10M users
- 11Failure scenarios
- 12Reliability and observability
- 13Security
- 14Trade-offs
- 15Final architecture
- 16Interview discussion
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