CORS Tester

Use this little website to test if a URL is setup correctly to work with CORS.




If your CORS setup is not using a wildcard then this should be a domain that matches your AllowedOrigins


Shareable link:

Results

This URL will only work for specific domains.

What's that mean?

This url can only be loaded by pages that match https://rusosnith.static.observableusercontent.com. If you're trying to load it from a different origin and it's not working, you'll need to change it so the access-control-allow-origin header is set to *.

Headers

These are the response headers received when making the request.

access-control-allow-credentials: true
access-control-allow-headers: Accept, Authorization, Content-Type, Origin
access-control-allow-methods: GET, POST, OPTIONS
access-control-allow-origin: https://rusosnith.static.observableusercontent.com
cf-cache-status: DYNAMIC
cf-ray: 9371d584617b1cf4-ORD
connection: keep-alive
content-type: text/html; charset=UTF-8
date: Sun, 27 Apr 2025 22:42:38 GMT
link: ; rel="https://api.w.org/"
server: cloudflare
vary: Accept-Encoding, Origin
x-powered-by: PHP/7.4.33, PleskLin

CORS tester was built by @mscccc. The code is available on GitHub. Sponsored by HTML/CSS to Image.