CORS Checker

Check the Cross-Origin Resource Sharing (CORS) configuration of any URL.

The domain that will be making the request.

Checking CORS...

CORS Status

CORS Access

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Status Code

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Response Time

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CORS Headers
CORS Header Value
All Response Headers
Header Name Value
About CORS

Cross-Origin Resource Sharing (CORS) is an HTTP-header based mechanism that allows a server to indicate any origins (domain, scheme, or port) other than its own from which a browser should permit loading resources.

About CORS Checker

Check the Cross-Origin Resource Sharing (CORS) policy of a web server. Analyze Access-Control headers.

Request a web endpoint and inspect whether its Cross-Origin Resource Sharing headers permit the intended browser origin, method, and credentials mode.

Key features

  • Diagnostic scope Request a web endpoint and inspect whether its Cross-Origin Resource Sharing headers permit the intended browser origin, method, and credentials mode.
  • Target input Enter a complete HTTP or HTTPS endpoint and, where available, the Origin and request method you want to simulate.
  • Checks to review Review Access-Control-Allow-Origin, methods, headers, credentials, exposed headers, preflight behavior, and response status.
  • Diagnostic result The report highlights returned CORS policy and common mismatches that can make a browser block frontend access.

How to use CORS Checker

Follow this workflow to work with CORS response headers safely and accurately.

  1. Enter the target Enter a complete HTTP or HTTPS endpoint and, where available, the Origin and request method you want to simulate.
  2. Select the diagnostic scope Review Access-Control-Allow-Origin, methods, headers, credentials, exposed headers, preflight behavior, and response status.
  3. Run the network check Run the CORS response headers diagnostic and retain status, timing, returned values, and the observation point needed to reproduce it.
  4. Correlate the result The report highlights returned CORS policy and common mismatches that can make a browser block frontend access.

Usage tips

  • Test the exact scheme, host, and port because together they form the browser origin.
  • A wildcard origin cannot be combined with credentialed browser requests.
  • Check both the preflight OPTIONS response and the actual method response.

Frequently asked questions

Request a web endpoint and inspect whether its Cross-Origin Resource Sharing headers permit the intended browser origin, method, and credentials mode.
Enter a complete HTTP or HTTPS endpoint and, where available, the Origin and request method you want to simulate.
Review Access-Control-Allow-Origin, methods, headers, credentials, exposed headers, preflight behavior, and response status.
Server-side probes cannot reproduce every browser rule, cookie policy, private-network check, redirect, service worker, or CDN cache variation. Confirm the final behavior in browser developer tools.