CORS Checker for Security
Free CORS security checker — test Access-Control-Allow-Origin, wildcard origins, and credentialed cross-origin exposure on any URL. Quick Check, no signup.
- Access-Control-Allow-Origin and wildcard origin checks
- Credentialed CORS and origin-reflection analysis
- Allowlist-first policy and preflight guidance
What This Tool Checks
- Access-Control-Allow-Origin and wildcard origin checks
- Credentialed CORS and origin-reflection analysis
- Allowlist-first policy and preflight guidance
Why It Matters
A CORS security checker catches wildcard or reflected-origin policies that look fine in the browser while still letting untrusted sites read API or dashboard data. Those misconfigurations are easy to ship during integration and hard to notice later.
Best For
Best for API, frontend, and security teams that need a specialized CORS Checker before shipping cross-origin, credentialed, or split frontend/backend setups.
What To Do Next
Use the findings to confirm whether you need a tighter allowlist, safer credential handling, or a broader review of origin behavior across environments. Then re-run this CORS Checker after each policy change.
Related Resources
Frequently Asked Questions
A CORS security checker is a specialized CORS Checker for evaluating Access-Control-Allow-Origin, Access-Control-Allow-Credentials, and preflight responses. It tells you whether browsers can expose API or page data to untrusted origins — before a wildcard or reflected-origin policy becomes a data leak.