API First Design
ELI5 — The Vibe Check
API First Design means you write the API contract (like an OpenAPI spec) before writing any code — like drawing blueprints before building a house. Frontend and backend teams agree on the interface first, then work independently. It prevents the classic 'the API returns what now?' surprise that derails sprint demos.
Real Talk
API First Design is an approach where the API specification is created and agreed upon before implementation begins. Teams collaborate on the API contract (typically OpenAPI/Swagger), generate mock servers for frontend development, and implement the backend to match the spec. It enables parallel development and ensures consistent contracts.
When You'll Hear This
"API First means our frontend team starts building with mocks on day one, not week three." / "We generate server stubs and client SDKs from our OpenAPI spec — the contract is the source of truth."
Related Terms
Contract Testing
Contract testing verifies that two services agree on their API contract — the request format, response shape, and status codes. It's like checking that the
Design System
A Design System is the IKEA instruction manual for your entire product's UI. It defines every color, button size, spacing unit, and component so your app l
OpenAPI
OpenAPI is a standard way to describe your REST API in a YAML or JSON file.