API & cURL Tester

Practical guide

Using the API Tester

Send HTTP requests and inspect API responses.

Example

Input

GET https://jsonplaceholder.typicode.com/todos/1
Header: Accept: application/json

Expected result

An HTTP status and response body from the endpoint, if the browser request is permitted.

Supported inputs

GET, POST, PUT, or DELETE requests.
A URL, JSON headers, query parameters, and an optional request body.

Limitations

The browser's same-origin policy and destination CORS settings may block requests.
Only send requests to endpoints you are authorized to access; requests go directly to the destination.

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How api & curl tester works

A lightweight request builder for testing JSON APIs, inspecting status codes, and validating payload behavior in real time.

The request builder composes fetch calls in the browser using the selected method, URL, headers, and body payload.

Query parameters are merged into the final request URL so developers can validate search and filter behavior quickly.

The response panel surfaces status, headers, and body content to help teams inspect API output without leaving the tool.

Because this is a lightweight client-side utility, it is ideal for endpoint smoke tests and quick payload validation.

Working code examples

Fetch JSON APIJavaScript

const response = await fetch("https://jsonplaceholder.typicode.com/todos/1", {
  headers: { Accept: "application/json" },
});
const data = await response.json();
console.log(data);

Request with PythonPython

import requests

response = requests.get("https://jsonplaceholder.typicode.com/todos/1")
print(response.status_code)
print(response.json())

Send a requestcURL

curl -X GET "https://jsonplaceholder.typicode.com/todos/1" -H "Accept: application/json"

Edge cases and troubleshooting

CORS restrictions can block some browser requests, especially when hitting third-party APIs without the proper server-side headers.
Verify the request URL and HTTP method before testing to avoid hitting the wrong endpoint or resource.
If JSON is malformed, check the body format and ensure the content type aligns with the API expectations.
When debugging, compare the browser request against a curl command to isolate client or server-side issues.

Frequently asked questions

Can this test real production APIs?+

It can, provided the endpoint allows browser access and is not blocked by CORS or authentication requirements.

Why do I need query parameters in the builder?+

Many APIs use query strings for pagination, filtering, and sorting, so including them here makes request validation realistic and reproducible.

Does it support JSON request bodies?+

Yes. The tool can send structured JSON payloads for POST and PUT requests while keeping the workflow fast and developer-friendly.