Practical guidance
Inspect Cache-Control, ETag and Vary for caching, and Location for redirects. Servers may handle HEAD and GET differently. Record the method and final URL when comparing responses.
Before using this tool
Define what you need from HTTP headers inspector and prepare the relevant input. When diagnosing a live service, record the test time and connection conditions so you can compare results after configuration changes. Check findings against the documentation for your software.
Tool availability
This is currently an information page. No working form, calculations or submission to diagnostic services is available yet. The interface and supported input formats will be documented when functionality is released.