CORS Header Checker

API & Web

Check pasted CORS response headers for common preflight and credentialed-request errors.

Parameters

Input

Output

Auto-calculate

0 characters · 0 bytes

Use cases

When to use CORS Header Checker

Check pasted CORS response headers for common preflight and credentialed-request errors.

1Review CORS headers copied from browser DevTools

2Check whether credentials are compatible with the allowed origin

3Verify preflight methods and custom request headers

4Parse URLs, run XPath queries, and inspect HTTP status codes

5Build minimal reproducible HTTP requests for frontend/backend debugging

6Review error codes and API compatibility before release

Guidance

This is a static header checker. Proxy behavior, server routing, and browser preflight still need an end-to-end test.

Inspect the components and query parameters of an absolute URL.

Look up the standard meaning of an HTTP response status.

Turn common cURL requests into JavaScript Fetch or Axios code.

Test HTTP APIs directly from the browser.