Requirements · Design drill
Scope a chat app
Design messaging for two people. Messages should arrive while both are online and still be there tomorrow.
Produce these
Write them in order. A diagram that is not forced by a requirement does not count.
- 01
Functional requirements for send, receive, and history.
- 02
A delivery rule: what the sender is promised if the recipient is offline.
- 03
A retention rule with a duration.
- 04
The feature you refuse in the first design, and the box it would have added.
Pressure
Group chats of 500 people are now in scope.
Leave out
Voice calls, encryption design, and contact discovery.