Developer Tools
Check a URL for common CORS response headers and review permissive or missing values.
Use this CORS Header Checker to fetch a URL and inspect common CORS response headers such as Access-Control-Allow-Origin, Access-Control-Allow-Methods, Access-Control-Allow-Headers, Access-Control-Allow-Credentials, and Vary. It is useful for debugging browser requests, API integrations, frontend issues, and basic cross-origin configuration checks.
Use this CORS Header Checker to fetch a URL and inspect common CORS response headers such as Access-Control-Allow-Origin, Access-Control-Allow-Methods, Access-Control-Allow-Headers, Access-Control-Allow-Credentials, and Vary. It is useful for debugging browser requests, API integrations, frontend issues, and basic cross-origin configuration checks.
Use cors header checker when you need a fast browser-based result without extra setup. It works well for quick checks, one-off tasks, and routine formatting or calculation work.
Read step-by-step usage guidance, best practices, and common mistakes.
See common questions and answers about input, output, and tool usage.
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Input
https://example.com/api/status
Output
Status, final URL, and CORS header values
Useful when debugging frontend requests to APIs.
Input
https://example.com/data.json
Output
Status, final URL, and CORS header values
Helpful for checking whether a resource is exposed cross-origin.
Fix: This tool checks visible response headers, not full browser-side CORS behavior.
Fix: CORS behavior can vary by method, route, and infrastructure.
Fix: Use a full URL like https://example.com/api/data.
It shows common CORS-related response headers such as Access-Control-Allow-Origin and related values.
No. It is a header inspection tool, not a full browser CORS emulator.
Yes. That is one of its main use cases.
Real browser CORS behavior depends on method, credentials, preflight, origin, and route-specific logic.
It can be overly broad depending on the type of endpoint and whether credentials are involved.