What is OpenAPI 3.x?

OpenAPI is the industry-standard specification for describing RESTful APIs. Formerly known as Swagger, it enables automated code generation, documentation, and testing.

The API Standard

OpenAPI provides a machine-readable format for describing HTTP APIs, enabling tools to generate code, documentation, and test suites automatically.

Swagger Origins

Swagger 1.x and 2.x established the foundation for API description formats. The specification was donated to the OpenAPI Initiative in 2015 and evolved into OpenAPI 3.x.

OpenAPI 3.x

The current standard supports JSON and YAML formats, advanced schema definitions, multiple authentication schemes, webhooks, and links between operations.

Delphi Integration

sgcOpenAPI parses any OpenAPI or Swagger specification and generates native Object Pascal code — giving Delphi developers first-class API tooling.

What a Specification Describes

Endpoints & Operations

Paths, HTTP methods (GET, POST, PUT, DELETE), query parameters, headers, and request bodies are all defined in a structured format.

Schemas & Models

Data types, object properties, arrays, enumerations, and composition (allOf, oneOf, anyOf) describe the shape of request and response payloads.

Authentication

API keys, OAuth 2.0 flows, HTTP Bearer tokens, and OpenID Connect are defined as reusable security schemes applied to operations.

Bring OpenAPI to Delphi

Generate native Pascal SDKs from any OpenAPI specification.