h2check

Meta tag checker

Reads the title, meta description, canonical, robots directives and social tags a URL returns, and reports the resolved value of each rather than the raw attribute.

Checker offline. Follow the manual steps below, they give the same answer.

What it checks

  • Title and meta description, with their lengths.
  • The canonical URL, resolved against the document base, which is where a relative canonical on a staging host points at staging.
  • Robots directives from both the meta tag and the X-Robots-Tag header, and which wins when they disagree.
  • Open Graph and Twitter card tags, which of the four properties a card needs are missing, and what the card would say. The image named by og:image is not requested, so nothing here says the file exists.
  • A meta tag that appears outside the head. Google documents that it honours these, but parsers that stop at the closing head tag do not see them, so the page and the tool disagree.
  • Duplicate tags, where a second canonical or title silently overrides the first.

What is not stored

This checker runs on a server, and the server is not deployed yet, so the form above is disabled. The manual steps on the procedures below return the same answer from your own machine, and they are what the checker automates.

Limits

  • The served HTML is read. Tags a script injects after load are not seen, and that difference is the point of the rendering procedures below.
  • Only the URL you give is read, so a template problem affecting other pages is invisible here. The pages named by hreflang are not fetched either, which is why return links are reported as not measured.
  • The first 1,048,576 bytes of the document are read. When the head is longer than that, a tag that was not found is reported as not found in the part that was read, rather than as absent.
  • A tag being present and well formed says nothing about whether its content is any good.

Procedures that explain the result

Put it on your own page

Link to it with the value filled in, and the checker runs as soon as the page opens.

<a href="https://h2check.org/tools/meta-tags/">Meta tag checker</a>