About this tool
Raw header inspection is the starting point for diagnosing caching problems, unexpected redirects, CORS issues, and cookie scope misconfigurations. Unlike a browser's DevTools - which applies browser-side processing - this tool shows exactly what the server returned, including every hop in a redirect chain. IT leaders reviewing third-party vendor integrations or post-incident root-cause analysis will often want the raw picture rather than the graded view. For a security-focused analysis, use the Security Headers Checker.