Architecture Design Review

Approaching Design Reviews in Interviews

Architecture design reviews in staff-level interviews are fundamentally different from standard system design questions. Instead of building something from scratch, you're handed an existing design, often intentionally flawed, and asked to evaluate it. This tests a completely different muscle: the ability to read someone else's work, figure out what actually matters, and deliver feedback in a way that's constructive rather than adversarial.

The Systematic Review Framework

Structure your review around five dimensions, in this order:

1. Data Flow - Trace a request end-to-end. Where does data enter, how is it transformed, where does it persist? Look for single points of failure, unnecessary hops, and data consistency gaps.

2. Failure Modes - For each component, ask: "What happens when this fails?" Check for circuit breakers, retries with backoff, timeout configurations, and graceful degradation paths. The candidates who stand out are the ones who spot cascading failure scenarios that the original designers missed.

3. Scalability - Identify which components are stateful vs stateless, which are on the critical path, and where bottlenecks will show up at 10x load. Not everything needs to scale the same way.

4. Security - Authentication, authorization, data encryption at rest and in transit, input validation, and audit logging. At staff level, you should also be thinking about compliance implications (PCI, GDPR, SOC 2).

5. Operability - How will this system be deployed, monitored, and debugged? Are there runbooks? Can you roll back safely? What does the on-call experience look like?

Critique vs. Build: Key Differences

When reviewing an existing design, resist the urge to redesign the whole thing from scratch. Interviewers are evaluating your ability to work within constraints. The most effective approach is to acknowledge what works well, identify the highest-impact issues, and propose targeted improvements with clear rationale. Show that you understand the original designers probably had good reasons for their choices, even if you'd choose differently with the benefit of hindsight.

Communicating Trade-Offs

The hallmark of a staff engineer in design reviews is being able to frame trade-offs for different audiences. Practice presenting the same concern three ways: for a junior engineer (technical detail), for a peer staff engineer (architectural implications), and for a VP (business risk and timeline impact).