API Documentation Skill

Auto-generate comprehensive API documentation with examples, schemas, and interactive tools.

Instructions

You are an API documentation expert. When invoked:

Generate Documentation:
- Create API reference documentation
- Extract info from code comments
- Generate from OpenAPI/Swagger specs
- Include usage examples
- Document authentication methods
Interactive Documentation:
- Set up Swagger UI
- Configure Redoc
- Create interactive playgrounds
- Add try-it-out features
- Include code samples
Documentation Types:
- API reference guides
- Getting started tutorials
- Authentication guides
- Error handling documentation
- Rate limiting policies
Multi-Format Export:
- HTML documentation
- Markdown files
- PDF exports
- Postman collections
- SDK generation

Usage Examples

@api-documentation
@api-documentation --from-openapi
@api-documentation --interactive
@api-documentation --export-postman
@api-documentation --generate-sdk

Documentation Tools

Swagger UI

Setup with Express

const express = require('express');
const swaggerUi = require('swagger-ui-express');
const YAML = require('yamljs');

const app = express();

// Load OpenAPI spec
const swaggerDocument = YAML.load('./openapi.yaml');

// Serve Swagger UI
app.use('/api-docs', swaggerUi.serve, swaggerUi.setup(swaggerDocument, {
  customCss: '.swagger-ui .topbar { display: none }',
  customSiteTitle: 'My API Documentation',
  customfavIcon: '/favicon.ico'
}));

// Serve OpenAPI spec as JSON
app.get('/openapi.json', (req, res) => {
  res.json(swaggerDocument);
});

app.listen(3000, () => {
  console.log('API docs available at http://localhost:3000/api-docs');
});

Custom Swagger Options

const options = {
  explorer: true,
  swaggerOptions: {
    persistAuthorization: true,
    displayRequestDuration: true,
    filter: true,
    syntaxHighlight: {
      activate: true,
      theme: 'monokai'
    }
  },
  customCss: `
    .swagger-ui .topbar { background-color: #2c3e50; }
    .swagger-ui .info .title { color: #2c3e50; }
  `,
  customSiteTitle: 'My API - Documentation',
  customfavIcon: '/assets/favicon.ico'
};

app.use('/docs', swaggerUi.serve, swaggerUi.setup(swaggerDocument, options));

Redoc

Setup

const express = require('express');
const { createProxyMiddleware } = require('http-proxy-middleware');

const app = express();

// Serve OpenAPI spec
app.get('/openapi.yaml', (req, res) => {
  res.sendFile(__dirname + '/openapi.yaml');
});

// Serve Redoc
app.get('/docs', (req, res) => {
  res.send(`
    <!DOCTYPE html>
    <html>
      <head>
        <title>API Documentation</title>
        <meta charset="utf-8"/>
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <link href="https://fonts.googleapis.com/css?family=Montserrat:300,400,700|Roboto:300,400,700" rel="stylesheet">
        <style>
          body { margin: 0; padding: 0; }
        </style>
      </head>
      <body>
        <redoc spec-url='/openapi.yaml'></redoc>
        <script src="https://cdn.redoc.ly/redoc/latest/bundles/redoc.standalone.js"></script>
      </body>
    </html>
  `);
});

app.listen(3000);

Redoc CLI

# Install
npm install -g redoc-cli

# Generate static HTML
redoc-cli bundle openapi.yaml -o docs/index.html

# Serve with live reload
redoc-cli serve openapi.yaml --watch

# Custom options
redoc-cli bundle openapi.yaml \
  --output docs/index.html \
  --title "My API Documentation" \
  --options.theme.colors.primary.main="#2c3e50"

Stoplight Elements

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no" />
    <title>API Documentation</title>
    <script src="https://unpkg.com/@stoplight/elements/web-components.min.js"></script>
    <link rel="stylesheet" href="https://unpkg.com/@stoplight/elements/styles.min.css" />
  </head>
  <body>
    <elements-api
      apiDescriptionUrl="/openapi.yaml"
      router="hash"
      layout="sidebar"
    />
  </body>
</html>

Documentation from Code

JSDoc to OpenAPI

/**
 * @openapi
 * /api/users:
 *   get:
 *     summary: Get all users
 *     description: Retrieve a paginated list of all users
 *     tags:
 *       - Users
 *     parameters:
 *       - in: query
 *         name: page
 *         schema:
 *           type: integer
 *           minimum: 1
 *           default: 1
 *         description: Page number
 *       - in: query
 *         name: limit
 *         schema:
 *           type: integer
 *           minimum: 1
 *           maximum: 100
 *           default: 10
 *         description: Number of items per page
 *     responses:
 *       200:
 *         description: Successful response
 *         content:
 *           application/json:
 *             schema:
 *               type: object
 *               properties:
 *                 data:
 *                   type: array
 *                   items:
 *                     $ref: '#/components/schemas/User'
 *                 meta:
 *                   $ref: '#/components/schemas/PaginationMeta'
 *       401:
 *         $ref: '#/components/responses/UnauthorizedError'
 *     security:
 *       - bearerAuth: []
 */
router.get('/users', async (req, res) => {
  // Implementation
});

/**
 * @openapi
 * components:
 *   schemas:
 *     User:
 *       type: object
 *       required:
 *         - id
 *         - name
 *         - email
 *       properties:
 *         id:
 *           type: string
 *           description: User ID
 *           example: "123"
 *         name:
 *           type: string
 *           description: User's full name
 *           example: "John Doe"
 *         email:
 *           type: string
 *           format: email
 *           description: User's email address
 *           example: "john@example.com"
 */

TypeDoc (TypeScript)

/**
 * User management API
 * @module UserAPI
 */

/**
 * Represents a user in the system
 * @interface User
 */
interface User {
  /** Unique user identifier */
  id: string;
  /** User's full name */
  name: string;
  /** User's email address */
  email: string;
  /** User role */
  role: 'user' | 'admin';
}

/**
 * Get all users
 * @route GET /api/users
 * @param {number} page - Page number (default: 1)
 * @param {number} limit - Items per page (default: 10)
 * @returns {Promise<User[]>} List of users
 * @throws {UnauthorizedError} If not authenticated
 */
export async function getUsers(
  page: number = 1,
  limit: number = 10
): Promise<User[]> {
  // Implementation
}

/**
 * Create a new user
 * @route POST /api/users
 * @param {CreateUserRequest} data - User data
 * @returns {Promise<User>} Created user
 * @throws {ValidationError} If data is invalid
 * @throws {ConflictError} If email already exists
 */
export async function createUser(data: CreateUserRequest): Promise<User> {
  // Implementation
}

Python Docstrings (FastAPI)

from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from typing import List, Optional

app = FastAPI(
    title="User Management API",
    description="API for managing users and authentication",
    version="1.0.0",
    docs_url="/docs",
    redoc_url="/redoc"
)

class User(BaseModel):
    """
    User model representing a user account.

    Attributes:
        id: Unique user identifier
        name: User's full name
        email: User's email address
        role: User role (user or admin)
    """
    id: str
    name: str
    email: str
    role: str = "user"

@app.get("/api/users", response_model=List[User], tags=["Users"])
async def get_users(
    page: int = 1,
    limit: int = 10
) -> List[User]:
    """
    Get all users with pagination.

    Args:
        page: Page number (default: 1)
        limit: Number of items per page (default: 10)

    Returns:
        List of users

    Raises:
        HTTPException: If unauthorized (401)
    """
    # Implementation
    return []

@app.post("/api/users", response_model=User, status_code=201, tags=["Users"])
async def create_user(user: User) -> User:
    """
    Create a new user account.

    Args:
        user: User data including name, email, and optional role

    Returns:
        Created user object

    Raises:
        HTTPException: If validation fails (400)
        HTTPException: If email already exists (409)
    """
    # Implementation
    return user

Documentation Templates

Markdown API Reference

# API Reference

Base URL: `https://api.example.com/v1`

## Authentication

All API requests require authentication using a Bearer token:

```bash
Authorization: Bearer YOUR_ACCESS_TOKEN

Get your access token by calling the /auth/login endpoint.

Endpoints

Users

Get All Users

GET /api/users

Retrieve a paginated list of users.

Parameters

Name	Type	In	Required	Description
page	integer	query	No	Page number (default: 1)
limit	integer	query	No	Items per page (max: 100)

Response

{
  "data": [
    {
      "id": "123",
      "name": "John Doe",
      "email": "john@example.com",
      "role": "user"
    }
  ],
  "meta": {
    "page": 1,
    "limit": 10,
    "total": 42,
    "totalPages": 5
  }
}

Status Codes

200 OK - Success
401 Unauthorized - Missing or invalid authentication
500 Internal Server Error - Server error

Example Request

curl -X GET "https://api.example.com/v1/api/users?page=1&limit=10" \
  -H "Authorization: Bearer YOUR_TOKEN"

const response = await fetch('https://api.example.com/v1/api/users?page=1&limit=10', {
  headers: {
    'Authorization': 'Bearer YOUR_TOKEN'
  }
});
const data = await response.json();

import requests

response = requests.get(
    'https://api.example.com/v1/api/users',
    headers={'Authorization': 'Bearer YOUR_TOKEN'},
    params={'page': 1, 'limit': 10}
)
data = response.json()

Create User

POST /api/users

Create a new user account.

Request Body

{
  "name": "John Doe",
  "email": "john@example.com",
  "password": "SecurePass123!",
  "role": "user"
}

Response

{
  "id": "123",
  "name": "John Doe",
  "email": "john@example.com",
  "role": "user",
  "createdAt": "2024-01-15T10:30:00Z"
}

Status Codes

201 Created - User created successfully
400 Bad Request - Invalid request data
409 Conflict - Email already exists
401 Unauthorized - Authentication required

Error Handling

All errors follow a consistent format:

{
  "code": "ERROR_CODE",
  "message": "Human-readable error message",
  "details": {
    "field": "Additional error details"
  }
}

Common Error Codes

Code	HTTP Status	Description
UNAUTHORIZED	401	Authentication required
FORBIDDEN	403	Insufficient permissions
NOT_FOUND	404	Resource not found
VALIDATION_ERROR	400	Invalid input data
RATE_LIMIT_EXCEEDED	429	Too many requests

Rate Limiting

API requests are limited to:

100 requests per minute for authenticated users
20 requests per minute for unauthenticated requests

Rate limit headers are included in all responses:

X-RateLimit-Limit: 100
X-RateLimit-Remaining: 95
X-RateLimit-Reset: 1610000000

Pagination

All list endpoints support pagination with these parameters:

page - Page number (default: 1)
limit - Items per page (default: 10, max: 100)

Responses include pagination metadata:

{
  "data": [...],
  "meta": {
    "page": 1,
    "limit": 10,
    "total": 100,
    "totalPages": 10
  }
}

Versioning

The API uses URL versioning:

Current version: v1
Base URL: https://api.example.com/v1

Breaking changes will be introduced in new versions (v2, v3, etc.)


### Getting Started Guide

```markdown
# Getting Started

This guide will help you make your first API request.

## 1. Get Your API Key

Sign up at [https://example.com/signup](https://example.com/signup) to get your API key.

## 2. Make Your First Request

### Using curl

```bash
curl -X GET https://api.example.com/v1/api/users \
  -H "Authorization: Bearer YOUR_API_KEY"

Using JavaScript

const response = await fetch('https://api.example.com/v1/api/users', {
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY'
  }
});

const users = await response.json();
console.log(users);

Using Python

import requests

response = requests.get(
    'https://api.example.com/v1/api/users',
    headers={'Authorization': 'Bearer YOUR_API_KEY'}
)

users = response.json()
print(users)

3. Create a Resource

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

4. Handle Errors

Always check the response status:

try {
  const response = await fetch('https://api.example.com/v1/api/users', {
    headers: { 'Authorization': 'Bearer YOUR_API_KEY' }
  });

  if (!response.ok) {
    const error = await response.json();
    console.error('Error:', error.message);
    return;
  }

  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error('Network error:', error);
}

Next Steps

Read the API Reference
Explore code examples
Check out best practices
Join our developer community


## Documentation Generation Tools

### Docusaurus (Facebook)

```bash
# Create new site
npx create-docusaurus@latest my-docs classic

# Install OpenAPI plugin
npm install docusaurus-plugin-openapi-docs

# Configure
# docusaurus.config.js
module.exports = {
  plugins: [
    [
      'docusaurus-plugin-openapi-docs',
      {
        id: 'api',
        docsPluginId: 'classic',
        config: {
          api: {
            specPath: 'openapi.yaml',
            outputDir: 'docs/api',
            sidebarOptions: {
              groupPathsBy: 'tag'
            }
          }
        }
      }
    ]
  ]
};

# Generate docs
npm run docusaurus gen-api-docs all

# Serve
npm run start

Slate (Beautiful API Docs)

# Clone template
git clone https://github.com/slatedocs/slate.git my-api-docs
cd my-api-docs

# Install dependencies
bundle install

# Edit source/index.html.md
# Run server
bundle exec middleman server

# Build static site
bundle exec middleman build

ReadMe.io

# Install CLI
npm install -g rdme

# Upload OpenAPI spec
rdme openapi openapi.yaml --key YOUR_README_API_KEY

# Sync with GitHub
rdme openapi openapi.yaml --github --key YOUR_README_API_KEY

MkDocs (Python)

# Install
pip install mkdocs mkdocs-material

# Create new project
mkdocs new my-api-docs
cd my-api-docs

# Configure mkdocs.yml
site_name: My API Documentation
theme:
  name: material
  features:
    - navigation.tabs
    - navigation.sections
    - toc.integrate

nav:
  - Home: index.md
  - Getting Started: getting-started.md
  - API Reference: api-reference.md
  - Examples: examples.md

# Serve locally
mkdocs serve

# Build
mkdocs build

Code Examples Generator

Automatic Code Generation

// From OpenAPI spec
const CodeGen = require('openapi-client-axios-typegen');

async function generateSDK() {
  const api = await CodeGen.generateClient('openapi.yaml');

  // Generated TypeScript client
  const users = await api.getUsers({ page: 1, limit: 10 });
  const newUser = await api.createUser({
    name: 'John Doe',
    email: 'john@example.com'
  });
}

Multi-Language Examples

// examples-generator.js
const examples = {
  getUsersCurl: `curl -X GET "https://api.example.com/v1/api/users?page=1&limit=10" \\
  -H "Authorization: Bearer YOUR_TOKEN"`,

  getUsersJavaScript: `const response = await fetch('https://api.example.com/v1/api/users?page=1&limit=10', {
  headers: {
    'Authorization': 'Bearer YOUR_TOKEN'
  }
});
const data = await response.json();`,

  getUsersPython: `import requests

response = requests.get(
    'https://api.example.com/v1/api/users',
    headers={'Authorization': 'Bearer YOUR_TOKEN'},
    params={'page': 1, 'limit': 10}
)
data = response.json()`,

  getUsersGo: `client := &http.Client{}
req, _ := http.NewRequest("GET", "https://api.example.com/v1/api/users?page=1&limit=10", nil)
req.Header.Add("Authorization", "Bearer YOUR_TOKEN")
resp, _ := client.Do(req)`,

  getUsersRuby: `require 'net/http'

uri = URI('https://api.example.com/v1/api/users?page=1&limit=10')
req = Net::HTTP::Get.new(uri)
req['Authorization'] = 'Bearer YOUR_TOKEN'
res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http| http.request(req) }`
};

Best Practices

Documentation Content

Write clear, concise descriptions
Include code examples in multiple languages
Provide real-world use cases
Document all error codes
Include rate limits and quotas
Show authentication examples
Explain pagination
Document versioning strategy

Interactive Features

Add "Try it out" functionality
Include request/response examples
Show syntax highlighting
Provide copy-to-clipboard buttons
Add search functionality
Include navigation menu

Maintenance

Keep docs synchronized with code
Automate documentation generation
Version documentation with API
Review and update regularly
Test all code examples
Collect user feedback

SEO and Discovery

Use descriptive titles
Add meta descriptions
Create sitemap
Use proper heading structure
Include keywords
Make docs publicly accessible

Notes

Auto-generate docs from OpenAPI specs when possible
Include interactive API explorers
Provide examples in multiple programming languages
Keep documentation up-to-date with code changes
Use version control for documentation
Make documentation searchable
Include getting started guides
Document authentication thoroughly
Show error handling examples
Test all code examples before publishing
Collect and incorporate user feedback
Use consistent formatting and style

api-documentation