Free Online HTTP Header Checker

1. Enter the full URL you want to inspect, including http:// or https://.
2. Press Check — our server fetches the page and reads its response headers.
3. Note the status code and final URL at the top to confirm where the request landed.
4. Scan the header table for cache-control, content-type and any x-robots-tag set to noindex.
5. Compare two URLs by checking them in turn to confirm consistent caching and security headers.

HTTP response headers are the metadata a server attaches to every reply, defined by HTTP semantics in RFC 9110. They control how a page is cached (cache-control, expires, etag), how it is delivered (content-type, content-encoding, content-length), and how browsers should treat it for security (strict-transport-security, content-security-policy, x-frame-options). For SEO specifically, the status code and the x-robots-tag header matter most — an x-robots-tag set to noindex will quietly keep a page out of search results even when its on-page markup looks fine.

We fetch the URL on our server to avoid browser CORS limits: client-side JavaScript cannot read another origin's response headers, so a purely in-browser tool simply cannot do this. Our server makes the request with a normal GET, follows redirects, and returns the final URL alongside the full header set, so the headers you see belong to the page that actually answered.

Use it to confirm caching is configured, to verify HTTPS is enforced via HSTS, and to catch headers that silently block indexing before they cost you traffic.