Check the canonical tag on any public page and review the preferred URL being declared. You can also generate a clean self-referencing canonical tag when one is needed.
Canonical tags help search engines understand the preferred URL among duplicate or similar pages. This checker reports the observable canonical declaration without deciding whether a different URL should be canonical for your business.
Review whether the declared canonical is absolute, reachable and genuinely represents the preferred version of the content. Self-referencing canonicals are common on unique indexable pages.
Pointing every page to the homepage, canonicalizing to redirects or mixing contradictory canonicals across HTML and headers can create confusing signals.
Align canonicals with redirects, internal links and sitemap URLs, then recrawl affected templates and verify how search engines interpret the preferred URL.
A rel=canonical link identifies the URL you prefer search engines to treat as the representative version among duplicate or very similar URLs. It is a hint rather than an absolute command.
A self-referencing canonical is commonly used to make the preferred URL explicit and keep canonicalization consistent across templates. It should point to the actual preferred public URL.
A conflicting canonical can encourage search engines to consolidate signals toward another URL. Review canonicals carefully, especially on product variants, filters, pagination and copied templates.
The preferred canonical should normally be a valid accessible destination rather than a redirect, error page or blocked URL.
Cross-domain canonicals are supported in appropriate duplicate-content situations, but they should be used deliberately because they ask search engines to consolidate signals toward another domain.