HTTP & WebLOCALRuns in your browserInput may contain sensitive information
CORS Header Analyzer
Inspect supplied CORS response headers and optional preflight request details without contacting a server.
This tool handles input and primary processing in your browser and is designed not to send the input to QuickKit’s server.
Avoid live production secrets; use dummy or masked data where possible. Data handling details
Syntax and context notes
How it works
Paste response headers and, optionally, preflight request details. The tool checks local syntax and header relationships such as wildcard origins, credential mode, and Vary: Origin. It does not send a request, determine whether a live endpoint is accessible, or issue a security verdict.