How to Handle Functional Requirements in Frontend System Design Interviews

Frontend system design interviews often feel overwhelming because prompts like 'design a notification system' are intentionally vague and open to many interpretations. A practical first step is to establish functional requirements — defining what the system should allow users to do before thinking about architecture or implementation. For a notification system, this could include allowing users to receive, view, and mark notifications as read, as well as see an unread count in real time. Non-functional requirements, such as latency, scalability, and accessibility, then describe how well those features must perform. Asking clarifying questions during the interview is essential, as the prompt is deliberately incomplete and scoping the problem collaboratively with the interviewer is a key part of the evaluation.