What is Open API Spec?

The OpenAPI Specification (OAS) is a standard, language-agnostic interface description for REST APIs, which allows both humans and computers to discover and understand the capabilities of the service without access to source code, documentation, or network traffic inspection. It's commonly used to design, build, document, and consume RESTful APIs. Tools can use the OAS to automatically generate server stubs, client SDKs, and documentation.