API Tester Skill

Quick API endpoint testing with comprehensive request/response validation.

Instructions

You are an API testing expert. When invoked:

1. Test API Endpoints:

   • Validate HTTP methods (GET, POST, PUT, PATCH, DELETE)
   • Test request headers and body formats
   • Verify response status codes
   • Validate response schema and data types
   • Check authentication and authorization

2. Generate Test Cases:

   • Create curl commands for testing
   • Generate Postman collections
   • Write automated test scripts
   • Test edge cases and error scenarios
   • Validate API contracts

3. Performance Testing:

   • Load testing with concurrent requests
   • Response time benchmarking
   • Rate limit verification
   • Timeout handling
   • Connection pooling tests

4. Security Testing:

   • Authentication/authorization checks
   • Input validation testing
   • SQL injection prevention
   • XSS prevention
   • CORS configuration

Usage Examples

@api-tester
@api-tester --endpoint /api/users
@api-tester --method POST
@api-tester --load-test
@api-tester --generate-collection

REST API Testing

GET Request Examples

Basic GET Request

# curl
curl -X GET https://api.example.com/api/users \
  -H "Content-Type: application/json"

# With authentication
curl -X GET https://api.example.com/api/users \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json"

# With query parameters
curl -X GET "https://api.example.com/api/users?page=1&limit=10&sort=created_at" \
  -H "Authorization: Bearer YOUR_TOKEN"

# Verbose output (includes headers)
curl -v -X GET https://api.example.com/api/users

JavaScript/Node.js

// Using fetch
async function getUsers() {
  const response = await fetch('https://api.example.com/api/users', {
    method: 'GET',
    headers: {
      'Authorization': 'Bearer YOUR_TOKEN',
      'Content-Type': 'application/json'
    }
  });

  if (!response.ok) {
    throw new Error(`HTTP error! status: ${response.status}`);
  }

  const data = await response.json();
  return data;
}

// Using axios
const axios = require('axios');

async function getUsers() {
  try {
    const response = await axios.get('https://api.example.com/api/users', {
      headers: {
        'Authorization': 'Bearer YOUR_TOKEN'
      },
      params: {
        page: 1,
        limit: 10
      }
    });
    return response.data;
  } catch (error) {
    console.error('Error:', error.response?.data || error.message);
    throw error;
  }
}

Python

import requests

# Basic GET request
response = requests.get('https://api.example.com/api/users')
print(response.json())

# With authentication and parameters
headers = {
    'Authorization': 'Bearer YOUR_TOKEN',
    'Content-Type': 'application/json'
}

params = {
    'page': 1,
    'limit': 10,
    'sort': 'created_at'
}

response = requests.get(
    'https://api.example.com/api/users',
    headers=headers,
    params=params
)

if response.status_code == 200:
    data = response.json()
    print(data)
else:
    print(f"Error: {response.status_code}")
    print(response.text)

POST Request Examples

Create Resource

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

# From file
curl -X POST https://api.example.com/api/users \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d @user.json

JavaScript/Node.js

// Using fetch
async function createUser(userData) {
  const response = await fetch('https://api.example.com/api/users', {
    method: 'POST',
    headers: {
      'Authorization': 'Bearer YOUR_TOKEN',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify(userData)
  });

  const data = await response.json();
  return data;
}

// Usage
const newUser = {
  name: 'John Doe',
  email: 'john@example.com',
  role: 'user'
};

createUser(newUser)
  .then(user => console.log('Created:', user))
  .catch(error => console.error('Error:', error));

// Using axios with error handling
async function createUser(userData) {
  try {
    const response = await axios.post(
      'https://api.example.com/api/users',
      userData,
      {
        headers: {
          'Authorization': 'Bearer YOUR_TOKEN'
        }
      }
    );
    return response.data;
  } catch (error) {
    if (error.response) {
      // Server responded with error
      console.error('Error:', error.response.status);
      console.error('Message:', error.response.data);
    } else if (error.request) {
      // No response received
      console.error('No response from server');
    } else {
      console.error('Error:', error.message);
    }
    throw error;
  }
}

Python

import requests

# Create user
user_data = {
    'name': 'John

...