Mock Interview Prompt 003: Chat System
Mock Interview Prompt 003: Chat System
Prompt
Design a one-to-one and group chat system similar to WhatsApp or Slack messaging.
Interviewer Notes
Good candidates usually clarify:
- online vs offline delivery
- one-to-one vs group chat scope
- message ordering requirements
- read receipts and typing indicators
- attachment handling
Optional Follow-Ups
- Multi-device sync
- Message search
- End-to-end encryption
- Presence service
- Push notifications for offline users
What Strong Answers Usually Cover
- websocket or long-lived connection model
- message fan-out strategy
- message storage model
- ordering and delivery semantics
- unread counts and sync strategy
- handling large groups efficiently