Create API Documentation

# Create API Documentation

Generate comprehensive, developer-friendly API documentation following OpenAPI/Swagger standards and best practices.

## Documentation Sections

### 1. API Overview

**Introduction**
- API purpose and capabilities
- Base URL and versioning strategy
- Supported formats (JSON, XML, etc.)
- Rate limiting and quotas
- API stability and deprecation policy

**Getting Started**
- Prerequisites
- Authentication setup
- Making your first request
- Quick start examples
- SDKs and client libraries

### 2. Authentication

**Authentication Methods**
- API Keys
- OAuth 2.0 / Bearer tokens
- JWT tokens
- Basic Auth
- Custom authentication schemes

**Authentication Details**

Authorization: Bearer

**Security Best Practices**
- Token storage
- Token rotation
- Scope and permissions
- Rate limiting per token

### 3. API Endpoints

For each endpoint, document:

**Endpoint Format:**

POST /api/v1/users

Creates a new user in the system.

Authentication Required: Yes Rate Limit: 100 requests/hour

Request Headers

• Content-Type: application/json
• Authorization: Bearer {token}

Request Body

{
  "email": "user@example.com",
  "name": "John Doe",
  "role": "user"
}

Request Parameters

Parameter	Type	Required	Description
email	string	Yes	User’s email address
name	string	Yes	User’s full name
role	string	No	User role (default: user)

Response (201 Created)

{
  "id": "user-123",
  "email": "user@example.com",
  "name": "John Doe",
  "role": "user",
  "createdAt": "2025-10-01T12:00:00Z"
}

Response Codes

Code	Description
201	User created successfully
400	Invalid request body
401	Unauthorized
409	User already exists
429	Rate limit exceeded
500	Internal server error

Error Response

{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Invalid email format",
    "field": "email"
  }
}

Code Examples

cURL

curl -X POST https://api.example.com/api/v1/users \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -d '{
    "email": "user@example.com",
    "name": "John Doe"
  }'

JavaScript/TypeScript

const response = await fetch('https://api.example.com/api/v1/users', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'Authorization': `Bearer ${token}`
  },
  body: JSON.stringify({
    email: 'user@example.com',
    name: 'John Doe'
  })
});
const data = await response.json();

Python

import requests

headers = {
    'Content-Type': 'application/json',
    'Authorization': f'Bearer {token}'
}
data = {
    'email': 'user@example.com',
    'name': 'John Doe'
}
response = requests.post(
    'https://api.example.com/api/v1/users',
    headers=headers,
    json=data
)

### 4. Data Models

**Schema Definitions**

Define all data models used in requests and responses:

User Model

Field	Type	Description
id	string	Unique identifier
email	string	Email address
name	string	Full name
role	string	User role (user, admin)
createdAt	datetime	Creation timestamp
updatedAt	datetime	Last update timestamp

### 5. Error Handling

**Error Response Structure**
```json
{
  "error": {
    "code": "ERROR_CODE",
    "message": "Human-readable error message",
    "field": "field_name",
    "details": {}
  }
}

Common Error Codes

• VALIDATION_ERROR: Invalid input data
• AUTHENTICATION_ERROR: Invalid or missing authentication
• AUTHORIZATION_ERROR: Insufficient permissions
• NOT_FOUND: Resource not found
• RATE_LIMIT_EXCEEDED: Too many requests
• SERVER_ERROR: Internal server error

6. Pagination

Pagination Pattern

GET /api/v1/users?page=1&limit=20

Response Format

{
  "data": [...],
  "pagination": {
    "page": 1,
    "limit": 20,
    "total": 150,
    "totalPages": 8
  }
}

7. Filtering and Sorting

Filter Parameters

GET /api/v1/users?role=admin&status=active

Sort Parameters

GET /api/v1/users?sort=createdAt&order=desc

8. Webhooks

Webhook Events

• Event types
• Payload structure
• Signature verification
• Retry logic

9. Rate Limiting

Rate Limit Headers

X-RateLimit-Limit: 100
X-RateLimit-Remaining: 95
X-RateLimit-Reset: 1633046400

10. Versioning

Versioning Strategy

• URL-based: /api/v1/, /api/v2/
• Header-based: Accept: application/vnd.api+json; version=1
• Deprecation timeline
• Migration guides

Best Practices

Documentation Quality

• Use clear, consistent terminology
• Provide realistic examples
• Include error scenarios
• Keep documentation up-to-date with code
• Use OpenAPI/Swagger spec when possible

API Design

• Follow RESTful conventions
• Use appropriate HTTP methods
• Return meaningful status codes
• Implement proper error messages
• Version your API
• Support pagination for list endpoints
• Use consistent naming conventions
• Provide filtering and sorting options

Developer Experience

• Interactive API explorer (Swagger UI)
• Postman collection
• SDK code examples
• Sandbox environment
• API changelog
• Migration guides
• Support channels

Output Format

Create documentation in Markdown format that can be:

• Hosted on docs site
• Converted to OpenAPI/Swagger spec
• Used to generate interactive documentation
• Integrated into developer portal