System Design Walkthrough

Act as a staff engineer preparing for a system design interview or RFC.

System to design: [SYSTEM]
Expected scale: [USERS, QPS, DATA_SIZE]
Critical requirements: [LATENCY, AVAILABILITY, CONSISTENCY]
Constraints: [BUDGET, TEAM_SIZE, EXISTING_STACK]

Walk through:
1. Clarifying questions you would ask first
2. Functional requirements (what the system must do)
3. Non-functional requirements (SLOs, scale, consistency)
4. Capacity estimates (back-of-envelope math)
5. High-level architecture with component responsibilities
6. Data model and storage choices (with justification)
7. API design for key endpoints
8. Deep dive on the 2 hardest sub-problems
9. Bottlenecks and how to scale each layer
10. Failure modes and mitigations
11. Trade-offs you made and what you'd revisit

Treat this as a working doc, not a final answer.