🌐CORS Tester

Test CORS headers on any URL and see what the server returns.

CORS must allow requests from this tool's origin. Blocked requests indicate a CORS policy issue.

Target URL

Origin Header

Method

About CORS Tester

Test CORS (Cross-Origin Resource Sharing) headers on any API endpoint or URL. Send a request with a custom Origin header and inspect the CORS headers returned by the server. Helps diagnose CORS configuration issues when building web applications that call external APIs.

How to Use CORS Tester

1
Enter the URL
Type the API endpoint URL you want to test for CORS support.
2
Set origin and method
Enter the origin your app will be making requests from and the HTTP method.
3
Test and review headers
Click Test CORS to send the request and view the CORS response headers.

Common Use Cases

Debugging CORS errors in web application development
Verifying API CORS configuration before deployment
Testing cross-origin API access for third-party integrations
Learning how CORS works through hands-on testing

Frequently Asked Questions

What does CORS stand for?

CORS stands for Cross-Origin Resource Sharing. It is a browser security mechanism that restricts web pages from making requests to a different domain than the one serving the page.

Why does CORS blocking happen?

Browsers enforce CORS to prevent malicious websites from making unauthorized requests to other sites on behalf of users. Servers must explicitly allow cross-origin requests by returning appropriate CORS headers.