What is OpenAPI 3.x?

OpenAPI 3.x is a specification for building and documenting APIs. It allows both humans and machines to discover and understand the capabilities of an API without requiring access to source code, documentation, or network traffic inspection. It is commonly used to design, build, document, and consume RESTful APIs. The specification defines a standard, language-agnostic interface to REST APIs which allows both humans and computers to discover and understand the service's capabilities without access to source code, documentation, or through network traffic inspection. When properly defined via OpenAPI, a consumer can understand and interact with the remote service with a minimum amount of implementation logic. OpenAPI 3.x defines the structure and syntax of API definition files, which can be written in YAML or JSON format.