These are LLD questions of the kind Amazon actually asks — the patterns reported from Amazon's AI-engineering rounds, where design trade-offs, scale and failure modes matter as much as definitions. Treat this page as a mock interview: say every answer out loud before revealing it. If one surprises you, the lesson behind it is linked at the bottom.
Amazon LLD concept questions
Amazon's LLD rounds are often full 'machine coding' — design AND implement working code in the session. Design an in-memory rate limiter for an API: allow at most N requests per user per minute.
Asked in
In an Amazon LLD round, after your initial design, the interviewer says 'now support per-endpoint limits, not just per-user.' What's the cleanest way to extend a well-factored rate limiter?
Asked in
Amazon interviewers frequently ask 'walk me through why you split it this way' mid-design. What's the strongest way to answer that for a class you just created?
Asked in
How to use this page: Amazon rarely asks something you've never seen — they ask a standard LLD concept and then push one level deeper ("why?", "what would you do if..."). Master the concept in the LLD course lessons, and the follow-up stops being scary.
Keep practising: SOLID Principles, Strategy Pattern, Design a Parking Lot and UML Diagrams cover what most Amazon LLD rounds test.