OpenAPISwaggerdokumentaatiota

The OpenAPI Specification (OAS) is a widely adopted, vendor-neutral description format for RESTful APIs. It provides a machine-readable contract that describes endpoints, operations, parameters, request bodies, responses, and authentication methods. Documents can be authored in YAML or JSON and can be used to generate documentation, client SDKs, and server stubs. It is maintained by the OpenAPI Initiative, under the Linux Foundation.

The term Swagger originally referred to a set of tools and to the Swagger Specification, which described APIs using JSON or YAML. In 2015–2016 the specification was renamed to OpenAPI Specification, while the tooling retained the Swagger branding (Swagger UI, Swagger Editor, SwaggerHub). Today, Swagger tools are commonly used with OpenAPI descriptions to render interactive docs, validate API definitions, and generate code.

Structure: An OpenAPI document includes info (title, version), servers, paths with operations, and reusable components such as schemas, parameters, and responses. It supports security schemes (API keys, OAuth2, OpenID Connect), and supports vendor extensions. The specification emphasizes a clear, language-agnostic contract that can be consumed by both humans and machines.

Usage and impact: The combination of OpenAPI and Swagger tooling accelerates API design, development, testing, and integration. It enables contract-first design, automated client generation for many languages, and interactive exploration of APIs via Swagger UI or similar tools. The approach has become a common standard in API development, fostering interoperability and consistency across teams and services.