Testing and Debugging CORS

Testing with Tools

• Postman: Use Postman to test CORS settings by manually sending requests with different origins and headers.
• Browser Developer Tools: Use the network tab to inspect CORS requests and responses. Look for CORS-related errors and examine response headers.

Common CORS Errors

• No ‘Access-Control-Allow-Origin’ header: Indicates that the server did not respond with the required CORS headers.
• No ‘Access-Control-Allow-Credentials’ header: Indicates issues with handling credentials (cookies, authorization headers).
• Preflight request failed: Often due to incorrect handling of OPTIONS requests or missing CORS headers.