API Tester

Test REST APIs with custom headers and request body

Request

What is an API Tester?

An API Tester (also called REST API client or HTTP client) is a tool that allows developers to test and debug APIs by sending HTTP requests and viewing responses. It's similar to Postman but runs entirely in your browser without requiring installation. You can test GET, POST, PUT, DELETE, and other HTTP methods with custom headers and request bodies.

How to Use the API Tester

  1. Select the HTTP method (GET, POST, PUT, DELETE, etc.)
  2. Enter the API endpoint URL
  3. Add custom headers if needed (Authorization, Content-Type, etc.)
  4. For POST/PUT/PATCH requests, add a request body (JSON, XML, etc.)
  5. Click "Send" to execute the request
  6. View the response status, headers, and body
  7. Copy the response or use it for debugging

HTTP Methods Explained

  • GET: Retrieve data from the server (read-only)
  • POST: Send data to create a new resource
  • PUT: Update an existing resource completely
  • PATCH: Partially update an existing resource
  • DELETE: Remove a resource from the server
  • HEAD: Get headers only (no body)
  • OPTIONS: Check which methods are supported

Benefits of Using Our API Tester

  • ✅ No installation required - works in your browser
  • ✅ Test APIs instantly without authentication setup
  • ✅ Support for all HTTP methods
  • ✅ Custom headers and request body
  • ✅ View formatted JSON responses
  • ✅ Response time and size metrics
  • ✅ Copy responses with one click
  • ✅ Free and unlimited usage
  • ✅ Privacy-friendly - requests from your browser

Common Use Cases

  • 🔍 Test REST API endpoints during development
  • 🐛 Debug API integration issues
  • 📊 Verify API responses and status codes
  • 🔐 Test authentication and authorization
  • ⚡ Check API performance and response times
  • 📝 Document API behavior
  • 🎓 Learn how APIs work
  • 🔧 Quick API testing without Postman

Common Headers

  • Content-Type: application/json, application/xml, text/plain
  • Authorization: Bearer token, Basic auth, API key
  • Accept: application/json, application/xml
  • User-Agent: Identify your client application
  • Cache-Control: no-cache, max-age=3600

Tips for API Testing

  • 📌 Always check the API documentation first
  • 📌 Use proper Content-Type headers for JSON/XML
  • 📌 Test error cases (404, 500, etc.)
  • 📌 Verify response status codes
  • 📌 Check response times for performance
  • 📌 Use example endpoints to learn (jsonplaceholder.typicode.com)
  • 📌 Save common requests for reuse

🔧 Related Tools

→ JSON Formatter→ JWT Decoder→ Base64 Converter