HTTP Headers Checker - Free SEO tool

Some of the most consequential SEO directives never appear in the HTML. They travel in the HTTP response headers, invisible in the page source and in a browser's rendered view. A single X-Robots-Tag: noindex sent by a server can remove a page from search results while the HTML looks perfectly healthy.

The Sorank HTTP Headers Checker requests any URL and shows the full response, grouped so you can read it without knowing every header by heart.

The headers that decide whether a page ranks

X-Robots-Tag: the header version of the robots meta tag. It can carry noindex, nofollow, noarchive and more, and it applies to non-HTML files too, which is how PDFs and images get excluded.
Status code: a page that answers 200 is indexable, a 301 passes signals to its target, a 302 declares a temporary move, and a 404 or 410 removes the page. Sites regularly serve the wrong one by accident.
Location: the destination of a redirect, which tells you whether the chain ends where you think it does.
Canonical link header: a canonical can be declared in a header rather than in the head, and the two sometimes disagree.

Caching and speed

Headers also decide how much of your site a returning visitor has to download again:

Cache-Control sets how long a response may be reused. Static assets deserve a long max-age, HTML usually does not.
ETag and Last-Modified let a browser ask whether anything changed instead of downloading the file again.
Content-Encoding shows whether the response was compressed with gzip or brotli. An uncompressed HTML response is an easy win left on the table.

Security headers

They do not rank a page, but they protect the people on it, and their absence shows up in audits:

Strict-Transport-Security forces HTTPS for future visits.
Content-Security-Policy limits which scripts and styles may run.
X-Content-Type-Options stops browsers from guessing a file's type.
Referrer-Policy controls what your site leaks to the pages it links to.

When to run this check

A page disappeared from search and the HTML shows nothing wrong. Check X-Robots-Tag first.
After a migration or a CDN change, when redirect rules and cache policies are rewritten in bulk.
On a staging server that leaked into production, where a blanket noindex header often survives the move.
Before a performance push, to see what is cached, what is compressed, and what is neither.

Frequently asked questions

What is the X-Robots-Tag header and why does it matter?

It carries the same instructions as the robots meta tag, but in the HTTP response rather than the HTML. Because it is invisible in the page source, a noindex sent this way is one of the hardest indexing problems to diagnose. It also applies to files that have no HTML at all, such as PDFs.

Which security headers should every site send?

Strict-Transport-Security, X-Content-Type-Options set to nosniff, a Referrer-Policy, and a Content-Security-Policy adapted to what your pages actually load. They do not improve rankings on their own, but their absence is flagged by most audits and by some enterprise buyers.

Do response headers affect page speed?

Yes, through caching and compression. Cache-Control and ETag decide how much a returning visitor downloads again, and Content-Encoding decides how heavy each response is on the wire. Both feed directly into Largest Contentful Paint on repeat visits.