Glossary

OpenAPI / Swagger

OpenAPI is a standard for machine-readable REST API descriptions in YAML or JSON format. Swagger is the toolset built around this standard (Swagger UI, Swagger Editor). Documentation that never goes stale — generated from code or used as the source of truth for code generation.

What it provides

Interactive documentation (Swagger UI) — test endpoints directly in the browser
Client SDK generation — automatic TypeScript/Python/PHP client from the API description
Request and response validation against the specification
A contract between frontend and backend — describe the API first, then implement it

Minimal example

paths:
  /users/{id}:
    get:
      summary: Get user
      parameters:
        - name: id
          in: path
          required: true
          schema:
            type: integer