Design-First vs Code-First

API Design Approaches

In code-first development, implementation is created first and documentation is generated from code annotations or runtime metadata.

In design-first development, the API contract is designed before implementation. Teams can review resource models, status codes, schemas, and security requirements before writing server code.

Design-first is especially useful for teams with multiple consumers because frontend and backend developers can work against a shared contract.

Approaches
Code-first: Implementation → contract
Fast for implementation-oriented teams.
Design-first: Contract → implementation
Useful for collaboration and early API review.