Email job queue
Design a simple background job/queue for sending emails in a small SaaS app (signup confirmations, password resets, notifications). When something triggers an email, the web request should return immediately rather than waiting on the mail provider. Volume is a few thousand emails a day. Describe how a job gets enqueued, processed, and what happens when sending fails.
What a strong answer looks like
Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts (data model, bottlenecks, consistency, failure modes) and name the trade-offs you are making.
Clarify3:30 left
Estimate3:30 planned
Design10:00 planned
Deep dive8:00 planned
Failure5:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.