Chat apps vary in complexity. Clarify scope.
Functional requirements:
- Send and receive messages in real-time
- View conversation list
- See message status (sent, delivered, read)
- Typing indicators
- Support text, images, files
Non-functional requirements:
- Messages appear within ms
- Handle k+ messages per conversation
- Work offline with sync
- Low battery consumption
Scope for interview: Focus on : chat. Defer group chat, threading, and search.