Amazon’s loop for SDE-2 and above includes 1-2 system design rounds alongside coding and behavioral (Leadership Principles) rounds. System design is evaluated on scalability, availability, and the ability to make clear trade-offs. Amazon values operational excellence - expect questions about monitoring, failure modes, and blast radius.
Lead with Leadership Principles. Even in system design, tie decisions back to “Customer Obsession,” “Bias for Action,” and “Ownership.” Amazon evaluates how you think, not just what you design.
Discuss operational readiness. Monitoring, alerting, runbooks, blast radius, and graceful degradation are expected in every design answer.
Quantify your design. Back-of-envelope math (QPS, storage, bandwidth) shows you can reason about scale. Amazon operates at massive scale - show you understand the numbers.
Address failure modes explicitly. What happens when a service goes down? How do retries work? What’s the dead-letter strategy? Amazon interviewers probe resilience deeply.