Core Concepts

Question 1

What are the stages that you should target within a complete system design interview?

Answer 1

• Requirements
• Entities
• API / Interfaces
• Data Flow (Optional)
• High Level Design
• Deep Dive

Question 2

What are the three most important steps to define within the requirements stage of a system design interview?

Answer 2

• Define core requirements/functionality (bare minimum of what the system needs to do to function, try to target 3)
• Define non-functional requirements (e.g., scale, latency, etc.)
• Discuss scale (doesn’t require back of napkin math necessarily, suggest not going too overly in the weeds and come back if needed)

Question 3

In the entities stages of a system design interview, what’s the goal and easiest approach to handle that?

Answer 3

It’s to define all of the entities that play a role in the system so they can be discussed throughout the design. Typically a simple bulleted list with some properties can be enough.

Question 4

What are the three primary types of APIs you should focus on during a system design interview?

Answer 4

REST, GraphQL, and RPC

Question 5

Out of the three major API types, when would you use each within a system design interview?

Answer 5

You would use:
- REST - almost always, best general purpose option
- GraphQL - if you have a large number of diverse clients with different requirements
- RPC - generally reserved for service-service calls, ultra high performance in distributed systems/internal APIs

Question 6

Data flow can be a popular optional step during a system design interview, what’s its purpose?

Answer 6

As the name states, it simply walks through how data flows through the system and denoting each stage.

Question 7

If you hear the term over-fetching or under-fetching with regard to APIs, what technology should you consider?

Answer 7

GraphQL