CORS Checker
Free online CORS policy checker tool
What is CORS?
CORS (Cross-Origin Resource Sharing) is a security mechanism that allows a web page to request resources from a different domain than the one serving the page. Without CORS, browsers block cross-origin requests to protect users from malicious websites. CORS headers tell the browser which origins, methods, and headers are permitted.
How to Check CORS Configuration
Enter the URL of the API or resource you want to test. Click Check CORS to see whether the server allows cross-origin requests. The tool shows the Access-Control-Allow-Origin, Allow-Methods, and Allow-Headers values if CORS is enabled.
▶Why do I get CORS errors in my web app?
CORS errors occur when your frontend JavaScript tries to call an API on a different domain, and the server does not include the proper CORS headers. The server needs to send Access-Control-Allow-Origin with your domain (or *) in the response.
▶What is a CORS preflight request?
Before certain cross-origin requests, the browser sends an OPTIONS request (preflight) to check if the actual request is allowed. The server must respond with appropriate CORS headers for the actual request to proceed.
▶Is setting Access-Control-Allow-Origin: * safe?
For public APIs, allowing all origins (*) is fine. For authenticated endpoints, you should specify exact origins to prevent unauthorized websites from making requests on behalf of your users.