What is OpenAPI?

OpenAPI is a widely adopted specification for describing RESTful APIs, enabling both humans and machines to understand and interact with APIs without accessing the source code. Originally known as Swagger until version 3.0, it became OpenAPI under the Linux Foundation's OpenAPI Initiative in 2016. The specification supports writing API definitions in YAML and JSON, with YAML being favored for its readability. OpenAPI facilitates a design-first approach, allowing teams to define APIs before coding, thus serving as a single source of truth for organizations. It contrasts with the code-first approach, which can be useful for rapid development. Numerous tools, like OpenAPI-GUI and Swagger Editor, assist in editing, documenting, mocking, and testing APIs. OpenAPI's benefits include enhanced collaboration and streamlined API design processes, and users are encouraged to explore public API definitions and tools to develop their own APIs.