HLD Interview Framework

A structured approach to ace system design interviews in 45 minutes

Total: ~45 minutes
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Ask clarifying questions to narrow the scope. Understand functional requirements (what the system does) and non-functional requirements (how it performs). Define the boundaries of the problem.

Tips

  • Ask about scale: How many users? DAU/MAU? Requests per second?
  • Ask about features: What are the core features vs nice-to-haves?
  • Ask about constraints: Latency requirements? Availability targets? Consistency needs?
  • Define the read:write ratio — this heavily impacts architecture
  • Ask who the users are (end users, developers, internal)
  • Clarify data retention and compliance requirements
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