An API tester lets you send HTTP requests with custom methods, headers, and body from your browser and inspect the response — status code, headers, body, and timing. It is a lightweight browser-based alternative to Postman for testing CORS-enabled REST APIs.
Response
Request History
No history yet. Send a request to start.
Access-Control-Allow-Origin: *.
How to Use the API Tester
The API tester uses the browser's built-in fetch() API to send HTTP requests. It supports all common REST methods with full control over headers, request body, and authentication — making it a quick browser-based alternative to Postman for testing CORS-enabled APIs.
Step 1: Configure the Request
Select the HTTP method (GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS) and enter the full API URL. The pre-filled URL uses JSONPlaceholder, a free mock API you can use to test the tool immediately.
Step 2: Add Headers and Body
Use the Headers tab to add custom headers as key-value pairs. Click + Add Header to add more rows. For POST/PUT/PATCH, switch to the Body tab to add a request body in JSON, URL-encoded form, or raw text format.
Step 3: Authentication
Click the Auth tab to configure authentication. Bearer Token adds Authorization: Bearer {token} automatically. Basic Auth encodes your username and password in base64 and adds the appropriate Authorization header.
Reading the Response
The response panel shows the HTTP status code (color-coded: green for 2xx, orange for 4xx, red for 5xx), response time, and body size. JSON responses are automatically syntax-highlighted. Switch to the Headers tab to inspect all response headers.
FAQ
Is this API tester free?
Yes, the API tester is completely free with no account required. Send unlimited HTTP requests to any CORS-enabled API endpoint.
Why am I getting a CORS error?
Browser-based API testing is limited by CORS (Cross-Origin Resource Sharing) policy. The API server must include Access-Control-Allow-Origin headers. If the API doesn't support CORS, use a browser extension to bypass CORS or use a server-side tool like curl. This is a browser security constraint, not a bug in this tool.
What HTTP methods are supported?
The tool supports GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS methods. Request body input is shown for POST, PUT, and PATCH requests. For GET, DELETE, HEAD, and OPTIONS, the body field is hidden.
How do I add authentication?
Click the Auth tab to add authentication. Choose Bearer Token to enter a JWT or API key (it is added as Authorization: Bearer <token> header automatically), or choose Basic Auth to enter a username and password (encoded as base64 in the Authorization header).
Is my request history saved?
Yes. The last 10 requests are saved in your browser's localStorage. Click any item in the History section to restore the full request configuration — method, URL, headers, and body — so you can quickly re-send or modify previous requests.
Can I send JSON in the request body?
Yes. Set the body format to JSON, paste your JSON payload in the body textarea, and the tool automatically adds Content-Type: application/json to the request headers if not already present. The response body is also formatted with syntax highlighting when it contains JSON.