OpenAPI Specification

The OpenAPI Specification (formerly Swagger) is a standard, machine-readable format — written in YAML or JSON — for describing a REST API: its endpoints, parameters, request and response shapes, authentication, and error codes. A single `openapi.yaml` file becomes the single source of truth for what the API does. Its real power is tooling. From one spec you can auto-generate interactive documentation, typed client SDKs in a dozen languages, server stubs, mock servers, and contract tests — so the docs, the client, and the server never drift apart. For SaaS builders this matters in two directions. When you publish an API, shipping an OpenAPI spec makes your product dramatically easier to integrate, because customers can generate a client instead of hand-coding requests. When you consume a tool's API, the presence of a good spec is a strong signal of integration quality and saves you days of guesswork. It underpins ecosystems like Postman and drives the API import features in most iPaaS platforms.