server-assisted
HTTP headers
Status line, redirect chain and every response header of a URL, grouped by purpose.
we send one GET request from our server and read only the response headers
Enter a URL above to fetch its headers.
What this shows
One GET request is made from our servers and only the response headers are read — bodies are never downloaded. You get the status line, every redirect hop with its Location, and the full header set of the final response, grouped by what each header is for.
The redirect chain is often the interesting part: a single extra hop from http to https to www costs a round trip on every cold visit, and chains that loop or drop to plain HTTP in the middle are visible here in a way they are not in a browser.
Why do the headers differ from what my browser's devtools show?
The browser sends your cookies, your session and your Accept-Language, and it may be served from a CDN node near you. This request arrives cold and anonymous, which is how crawlers and monitoring see the site — usually the version worth checking.
Is a redirect chain actually a problem?
Each hop is a full round trip before anything renders, and search crawlers spend budget on them. Redirecting http://example.com straight to https://www.example.com in one step instead of two is a measurable win on mobile connections.
Why is the body not fetched?
Because nothing here needs it. Reading only headers keeps memory flat, avoids downloading megabytes to answer a question about a few hundred bytes, and means the tool cannot be turned into a bandwidth amplifier.
Can I inspect a URL behind authentication?
No. The request carries no credentials and no cookies, so you see exactly what an anonymous client sees. Anything requiring a session will return its login or error response, which is itself the honest answer.
Related tools: Security headers, CSP analyzer and SSL / TLS audit.