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CORS Checker

The CORS Checker sends a controlled cross-origin test and reports the response headers a browser uses to allow or block frontend access. It gives an immediate, focused result with no signup, explains the important limits beside the output, and keeps the workflow as private as the implementation allows.

Last updated · Free, no signup

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What does a CORS checker test?

A CORS checker tests whether a web server's response headers allow browser code from a specified origin to read a resource. It surfaces Access-Control-Allow-Origin and related preflight behavior, which helps distinguish a browser-enforced cross-origin restriction from an endpoint, authentication, or general network failure.

The controlled request is sent through a server endpoint protected by the shared SSRF guard so public targets can be inspected safely. A successful result applies only to the tested origin, method, and requested headers; it does not grant every site access, and command-line clients such as curl do not enforce CORS at all.