System Design: Practice High-Level Architecture Interviews

The System Design Framework

Every system design interview follows the same structure. Practice it until it is automatic:

1. Clarify requirements (5 min) — Functional requirements (what it does) and non-functional (scale, latency, availability)
2. Estimate scale (3 min) — Users, requests/sec, data stored
3. High-level design (10 min) — Main components and their relationships
4. Deep dive (20 min) — Database schema, API design, key algorithms
5. Tradeoffs (5 min) — What did you sacrifice? What would you change at 10x scale?

You are a staff engineer interviewing me for a system
design role. Give me this problem:

"Design [system: URL shortener / rate limiter / 
 news feed / ride-sharing / distributed cache]"

Conduct the interview interactively:
1. Ask me clarifying questions before I start
2. Let me present my design step by step
3. Ask follow-up questions like a real interviewer:
   "How would you handle 10x traffic?"
   "What happens if your database goes down?"
   "Why did you choose SQL over NoSQL here?"
4. At the end, give me feedback on:
   - What I covered well
   - What I missed
   - How my answer compares to a strong candidate

Systems to Know Cold

• URL shortener — Hashing, redirect, analytics. Great starter problem.
• Rate limiter — Token bucket, sliding window. Tests concurrency thinking.
• News feed — Fan-out, push vs pull, caching. Tests scale reasoning.
• Distributed cache — Consistent hashing, eviction policies, replication.
• Search autocomplete — Trie, prefix matching, ranking.