Lookup

HTTP Headers & Redirects

View the server's HTTP response headers, status codes and the full redirect chain including response times.

About this tool

The tool sends a browser-like request to the given address and follows every redirect. For each step it shows the status code, HTTP version, server IP address, response time and the complete response headers. Useful for debugging redirects from HTTP to HTTPS or from the non-www domain, and for checking cache headers, cookies and server configuration.

Glossary

HTTP and HTTPS
The protocol for transferring web pages. HTTPS is its encrypted variant over TLS, an HTTP address should today only redirect to HTTPS.
Status code
A three-digit number in the server response: 2xx success, 3xx redirect, 4xx request error (404 not found), 5xx server error.
Redirects 301, 302, 307, 308
301 and 308 are permanent (search engines move ranking to the new address), 302 and 307 temporary. 307 and 308 also keep the request method.
HTTP header
Additional information in the server response, e.g. Content-Type (type of content), Cache-Control (caching) or Server (server software).
HTTP/2 and HTTP/3
Newer protocol versions that transfer multiple files over one connection, so the website loads faster. HTTP/3 runs over UDP (QUIC).

How to use

  1. 1Enter a URL - to test the HTTPS redirect, start with http://.
  2. 2Click Fetch headers.
  3. 3Go through the redirect chain and the status codes.
  4. 4Expand the headers of any step and copy them if needed.
  5. 5Continue to the security headers grade.

Specifications and limits

The GET method is used and the response body is not downloaded. At most 10 redirects are followed and each step has a 10 second limit. Every step is checked against private and internal addresses. The certificate is not verified while fetching headers - use SSL Checker for that. An address without a protocol gets https:// added.