Free Online Meta Tag Analyzer and Head Tag Checker

Every other tool on this site runs entirely in your browser. That is a deliberate choice, and for most jobs it costs nothing: formatting JSON, converting colours or writing meta tags needs no help from anybody. Reading another site’s page is different. The same-origin policy stops a page on one domain from reading the response of a request to another domain, unless that other domain has explicitly opted in with a CORS header. Almost no website does. So a purely in-browser meta tag checker would work on about one site in a thousand, and fail silently on the rest.

The way round it is a small server-side fetcher, and this site has exactly one, shared by three tools. When you press Fetch, the URL you typed is sent to it, it makes the request, and it hands back the HTML it received. It refuses anything that is not http or https, and it refuses any host that resolves to a private, loopback or reserved address, so it cannot be used as a way into a network it should not reach. No cookies are sent with the request, which is why a page behind a login comes back either as a sign-in form or as nothing useful.

If none of that appeals, the Paste HTML mode does the whole analysis with no server involved at all. Open the page you want to check, view its source, copy it, and paste it in. Every check runs exactly the same way, because the checks were written against the parsed document and never care where the text came from.

About the Meta Tag Analyzer

A page’s head is where a surprising amount of trouble hides. The tags are invisible in the browser, they come from three unrelated specifications, and nothing complains when one is missing, spelled wrongly or pointing at the wrong address. The usual way this gets noticed is when a link shared in a chat app shows the wrong title, or when a page that should be indexed quietly is not. This tool exists to make that visible before somebody else finds it.

It reads the page with DOMParser, which is the same parser the browser itself uses, so malformed markup is handled the way a real browser would handle it rather than by a guess at a regular expression. Each check then asks one narrow question of the parsed document: is the tag there, is its value plausible, and does it agree with the other tags that claim to describe the same thing. A canonical that points somewhere else, an og:url that disagrees with it, or two h1 elements are all caught by comparison rather than by presence alone.

The hard part was honesty about what a single page can tell you. Plenty of checkers award a score that looks precise and quietly counts checks that never applied, or claim to verify things they cannot see. Here the score is out of the checks that actually ran, hreflang reciprocity is reported as uncheckable from one page because it is, and the fact that nothing JavaScript adds after load is visible is stated on the page rather than buried. A tool that overstates what it knows is worse than no tool.