CORS Headers Checker

Validate and explain CORS headers for cross-origin requests.

Access-Control-Allow-Origin *

Specifies which origins are allowed

Access-Control-Allow-Methods

Allowed HTTP methods for cross-origin requests

Access-Control-Allow-Headers

Allowed request headers

Access-Control-Allow-Credentials

Allow cookies/credentials

Access-Control-Max-Age

Preflight cache duration in seconds

Access-Control-Expose-Headers

Headers accessible to JavaScript

Response Headers Preview

Access-Control-Allow-Origin: *

About this tool

Validate and explain CORS headers for cross-origin requests.