Online API Tester

What is Online API Tester?

An online API tester sends HTTP requests to any URL and shows the response. Input: HTTP method (GET/POST/PUT/PATCH/DELETE), URL, headers (JSON), and body. Output: status code, formatted response body, and request time in milliseconds. Use it to debug REST APIs, test parameters, and verify endpoints. Note: browser CORS policies may block some cross-origin requests.

▶Use Cases5 scenarios
  • ◆REST API debugging
  • ◆Endpoint parameter testing
  • ◆Backend verification
  • ◆Status code checks
  • ◆Frontend integration
▶How to Use5 steps
  1. 1Pick an HTTP method (GET/POST/PUT/PATCH/DELETE)
  2. 2Enter the request URL
  3. 3Optional: add headers as JSON
  4. 4Optional: add a body for POST/PUT/PATCH
  5. 5Click Send to see status, response, and timing
▶Features8 features
  • ✓Completely free
  • ✓5 HTTP methods
  • ✓Custom headers
  • ✓Request body support
  • ✓JSON response formatting
  • ✓Request timing
  • ✓Status code display
  • ✓No signup
▶FAQ6 questions
What is an online API tester?

An online tool that sends HTTP requests to any URL and displays status code, response body, and timing. Input: method, URL, optional headers and body. Output: formatted response. Used for debugging REST APIs and verifying endpoints.

Which HTTP methods are supported?

Five: GET, POST, PUT, PATCH, DELETE. The request body field applies to POST, PUT, and PATCH only.

Why do some requests fail?

Browser CORS policies can block cross-origin requests. The error message notes "CORS may block some requests". This is a browser security limit, not a tool bug.

How do I format headers?

As JSON, e.g., {"Authorization": "Bearer token"}. Leave {} for no custom headers.

Does it show request timing?

Yes. Total time in milliseconds is shown for every request, measured from click to full response.

Can I test a local server?

Yes, but localhost calls are subject to CORS. Start with a public API (e.g., jsonplaceholder.typicode.com) for reliable results.