Back to the map

Module 19 · Interview playbook · Lesson 1 of 4

The 45-minute design interview

TODO: one-sentence summary of The 45-minute design interview.

CoreMust-knowMid 10 minStub Updated Nov 2026

Why it matters

Explain the problem the 45-minute design interview solves and where it shows up in production systems.

The idea

The core mechanism, with one diagram.

Trade-offs

What you give up, and the failure modes to name before an interviewer asks.

In an interview

How to bring it up, how deep to go for a mid candidate, and the follow-up questions to expect.

Key takeaways

  • One sentence you can say out loud.
  • When to reach for it, and when not to.
  • The neighbouring topic to connect it to.
The 45-minute design interview · Backplane