Checkers & Validators
Canonical Tag Checker
Check a page's canonical tag for the classic failures: self-reference mismatches, redirect chains, conflicting header and HTML values, and loops.
What this checks
- Whether a canonical exists at all, in the HTML or the HTTP header.
- Whether the two agree — conflicting signals get both ignored.
- Whether it is self-referencing, and if not, where it points.
- Whether the target is a chain — A canonicalises to B, B canonicalises to C. Google ignores chains rather than following them.
- Whether the page is
noindexwhile also declaring a canonical, which is a direct contradiction.
The failure that costs the most
A page that was meant to rank quietly canonicalising to the homepage, usually from a CMS default or a template copy. It removes the page from results without any error anywhere.