01 · Mental Models

Before any component or pattern, you must think the right way. Interviewers care less about what you know and more about how you reason. Every topic here teaches you a thinking tool, not a fact.

Pattern to build: When you see a new problem, ask — What is the bottleneck? Who reads, who writes? What breaks at scale? What does the user actually need (availability vs consistency)?

Start with this lesson

From first principles, with a short quiz at the end of each.

  1. L1Latency, Throughput & AvailabilityLesson · 3 short sections and a 4-question quiz

Topics

  1. 01.1Why systems fail at scaleIntern
  2. 01.2Latency numbers every engineer must knowIntern
  3. 01.3Back-of-envelope estimationJunior
  4. 01.4CAP theorem — the fundamental constraintMid-level
  5. 01.5Consistency models spectrumMid-level