CORS Header Checker

Check pasted CORS response headers against an origin, method and credential mode.

Origin allowed -
Method allowed -
Credentials -

Enter the example value or paste your own input, choose the mode when one is available, and read the first result card for the direct answer. The output area gives a copyable block for code reviews, documentation, API tests, classwork or troubleshooting notes.

What the result means

The checker compares the request origin and method with the CORS headers and flags the common wildcard-with-credentials problem.

What is not included

It does not perform a browser preflight request. Paste the headers you want to reason about.

Privacy note

The calculation runs in your browser. Avoid pasting production secrets, credentials, private keys, customer data or regulated personal data unless your own policy allows browser-based tools.