Prototypes

Prototypes are early, preliminary versions of a product built to explore ideas, validate a design, and gather feedback before committing to full-scale development. In the API world a prototype is usually a working-but-hollow version of an interface — a mock server generated from a specification — that behaves like the real thing without any backend behind it. The point is to learn cheaply, catch problems while they are still easy to change, and get consumers reacting to something concrete early.

• Mock-driven - A specification is turned into a mock API that returns realistic responses, so the interface can be exercised before code exists.
• Design-first - Prototyping pairs naturally with a design-first workflow where the contract is agreed before implementation.
• Fast feedback - Prototypes surface developer-experience and modeling problems while they are cheap to fix.
• Rapid and disposable - Rapid prototyping favors throwaway iterations over polished, permanent code.

In real API operations, prototyping is the bridge between design and build: a team publishes an OpenAPI contract, stands up a mock from it, and lets partners integrate against the prototype while the production service is still being written. This is the “prototype-first” path — distinct from code-first — that lets the conversation about an API happen before the expensive work begins. As tooling gets more capable, these mocks increasingly double as the fixture that automated tests and agents run against, keeping the prototype useful well past the initial design phase.