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Requirements: ask what changes the design

The prompt says "shared albums" and nothing else. Which questions are worth your first five minutes, how do you turn "fast and highly available" into numbers you can design against, and what do you say out loud about the features you're leaving out?

12 minEasyStation: Requirements and scope

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Start a free lessonSee the path
  1. Interview & rubric
  2. Requirements and scope
  3. Back-of-the-envelope estimates
  4. API design
Interview Line — where this lesson sits

What you'll be able to do

  1. 1Explain the difference between functional and non-functional requirements, and name the five non-functional ones that most often shape a design — scale, latency, availability, consistency, durability.
  2. 2Choose the clarifying questions whose answers would change the design, skip the ones that wouldn't, and state an assumption when the interviewer leaves a number to you.
  3. 3Predict how a design changes when one non-functional requirement changes — stale reads allowed or not, 99.9% or 99.99% available — and write each requirement as a number with a list of what's out of scope.

Inside the lesson

steps
11
questions
13
simulations
0

More on the Interview Line

  1. Interview & rubric: 45 minutes, no answer keyOpen13 min
  2. Back-of-the-envelope: find the number that mattersMembers12 min
  3. API design: one line per requirementMembers12 min
  4. Data model: from endpoints to keysMembers14 min
  5. High-level design: every box answers to the boardMembers14 min