Cianplan

Level 1: Foundations · L1.5 Design method, requirements & non-functional requirements

Core entities and API first

Derive entities and an API from requirements before drawing.

12 min · Free

What you take away

  • Entities are the nouns in your requirements, plus the relationships and their cardinality.
  • Writing the API before the architecture forces every ambiguity into the open while it is still cheap to resolve.
  • Three to six endpoints cover a design-session scope; more than that means the scope was never cut.
  • Entities are not tables — the physical schema comes later and is free to look completely different.

How the class is laid out

  1. The problem
  2. The simple version
  3. From requirements to entities to API
  4. Entities are not tables
  5. Check your understanding