OpenAPI Specification

A standard format for describing REST APIs, enabling documentation and code generation.

OpenAPI Specification (formerly Swagger) is an industry-standard format for describing RESTful APIs. It allows both humans and machines to understand API capabilities.

Benefits of OpenAPI

Documentation: Auto-generate interactive API docs
Code Generation: Create client SDKs and server stubs
Validation: Verify requests and responses
Mock Servers: Generate fake APIs for testing
Testing: Create automated test cases

Key Components

Paths: API endpoints and operations
Schemas: Data models and types
Parameters: Query, path, and header params
Responses: Expected response formats
Security: Authentication methods

Code Examples

OpenAPI YAML

openapi: 3.0.0
info:
  title: Users API
  version: 1.0.0
paths:
  /users:
    get:
      summary: List users
      responses:
        200:
          description: Success

Related Terms

API Mocking

Simulating API behavior to enable development and testing without real backend services.

Mock API

A simulated API endpoint that returns predefined responses for testing and development.

WebSocket

A protocol enabling full-duplex, real-time communication between client and server.

HTTP Status Codes

Standard response codes that indicate the result of an HTTP request.