Api Documentation

Overview

API documentation provides clear, comprehensive information about API endpoints, parameters, responses, and usage examples.

Documentation Types

Reference Documentation

• Complete API reference
• All endpoints, parameters, responses
• Technical specifications

Guide Documentation

• Getting started guides
• Authentication tutorials
• Code examples and SDKs

Interactive Documentation

• Try-it-out functionality
• Live API testing
• Generated from OpenAPI specs

OpenAPI Specification

Basic Structure

openapi: 3.0.3
info:
  title: User Management API
  version: 1.0.0
  description: API for managing users
servers:
  - url: https://api.example.com/v1
paths:
  /users:
    get:
      summary: Get all users
      parameters:
        - name: limit
          in: query
          schema:
            type: integer
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/User'
components:
  schemas:
    User:
      type: object
      properties:
        id:
          type: integer
        name:
          type: string

Key Components

• Info: API metadata
• Servers: API server URLs
• Paths: Endpoint definitions
• Components: Reusable schemas
• Security: Authentication schemes

Documentation Tools

Swagger/OpenAPI Tools

• Swagger UI: Interactive documentation
• Swagger Editor: Design and edit specs
• Swagger Codegen: Generate client SDKs

Alternative Tools

• Redoc: Clean, responsive documentation
• Stoplight: Design, document, and test APIs
• Postman: API documentation with examples
• Apiary: Collaborative API design

Documentation Best Practices

Structure

• Overview: What the API does
• Authentication: How to authenticate
• Endpoints: Detailed endpoint documentation
• Examples: Code samples in multiple languages
• Errors: Error codes and messages

Content Guidelines

• Clear Language: Avoid jargon, explain terms
• Consistent Format: Standard structure for all endpoints
• Up-to-Date: Keep documentation current
• Comprehensive: Cover all use cases

Code Examples

# Get user by ID
curl -X GET "https://api.example.com/users/123" \
  -H "Authorization: Bearer YOUR_TOKEN"

// JavaScript example
const response = await fetch('/api/users/123', {
  headers: {
    'Authorization': 'Bearer YOUR_TOKEN'
  }
});
const user = await response.json();

# Python example
import requests
 
response = requests.get('/api/users/123', 
                       headers={'Authorization': 'Bearer YOUR_TOKEN'})
user = response.json()

Interactive Documentation

Swagger UI Features

• Try it out: Execute API calls directly
• Authentication: Test with real credentials
• Response Preview: See actual responses
• Schema Validation: Validate request/response formats

Benefits

• Immediate Testing: No separate tools needed
• Learning Tool: Understand API behavior
• Debugging Aid: Test edge cases
• Developer Experience: Integrated workflow

API Description Formats

API Blueprint

# User API
 
## GET /users/{id}
 
Get a specific user by ID.
 
+ Parameters
    + id (number) - User's unique identifier
 
+ Response 200 (application/json)
    + Attributes
        + id: 123 (number)
        + name: "John Doe" (string)

RAML

#%RAML 1.0
title: User API
version: v1
 
/users:
  get:
    description: Get all users
    responses:
      200:
        body:
          application/json:
            type: array
            items: User
  post:
    description: Create a new user
    body:
      application/json:
        type: UserInput
 
types:
  User:
    properties:
      id: integer
      name: string
  UserInput:
    properties:
      name: string

Documentation Maintenance

Version Control

• Keep specs in Git
• Version with API versions
• Review changes in PRs

Automation

• Generate from code annotations
• CI/CD documentation checks
• Automated testing from specs

Collaboration

• Use collaborative tools
• Review documentation changes
• Stakeholder feedback loops

Testing Documentation

Validation

• Schema Validation: Ensure specs are valid
• Link Checking: Verify all links work
• Example Testing: Test code examples
• Consistency Checks: Automated style checks

User Testing

• Developer Feedback: Get input from API consumers
• Usability Testing: Test documentation usability
• A/B Testing: Compare documentation versions

Metrics & Analytics

Usage Metrics

• Page views and time spent
• Search queries and results
• Popular endpoints and examples

Quality Metrics

• Documentation completeness
• Update frequency
• User satisfaction scores

Related

• Api Design
• Api Testing
• Api Management
• Documentation As Code