Explain and diagram your past system architecture evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Whiteboard the architecture of a real system you have built or owned. Describe the main components, data flows, storage choices, scaling and resiliency strategies, deployment/DevOps topology, and key trade-offs. Justify technology selections and discuss how the design evolved.
Overview: Explain and diagram your past system architecture evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Key trade-offs and technology selections (with rationale)
How the design evolved over time (v1 → vN, and why)
If you cannot disclose specifics, present an equivalent system (e.g., a document preview/thumbnail pipeline, notifications, or search indexing) and keep details non-proprietary.
Clarifying Questions to Ask Guidance
Clarify users, core use cases, read/write patterns, scale, latency, availability, and data retention.
State explicit assumptions before making sizing or architecture decisions.
Prioritize the functional path first, then address reliability, security, observability, and rollout.
What a Strong Answer Covers Guidance
A scoped requirements summary with concrete non-goals and success metrics.
API, data model, architecture, consistency, capacity, and operations.
Reasoned trade-offs among simple and scalable designs, including bottlenecks and failure modes.
A validation, monitoring, migration, and launch plan appropriate for the risk level.
Follow-up Questions Guidance
What breaks first at 10x traffic or data volume?
How would you degrade gracefully during dependency failures?
What metrics and alerts would prove the design is healthy after launch?