DigitalBanzai Knowledge

Canonical

Understand what a canonical is for and read the declaration TrustyRunner observes without assuming guaranteed effects.

Italian version
Severity
Moderate
Estimated fix time
15-45 min
Technical level
Beginner / Intermediate
Applies to
WordPressStatic HTMLCMS / E-commerceSEO Plugins

Quick answer

A canonical is an HTML declaration that indicates which URL a site considers the reference version. It can be useful where similar versions of a page exist, but it does not require Google or another search engine to choose that URL.

Why it may deserve attention

A missing, invalid, or inconsistent declaration may come from a template, plugin, or configuration. Before changing it, compare it with the URL the site intends to declare: a canonical to another domain or page can be intentional.

What TrustyRunner checks

TrustyRunner uses the first observed link rel="canonical" and compares it with the page's final URL. It observes presence, validity, self-reference, domain, scheme, www, and the number of canonicals within a limit.

It does not compare the declaration with sitemaps, redirects, or internal links, and does not retain the href as general output.

How to read the result

A missing or invalid canonical is reported only when evidence is conclusive. Multiple canonicals, a different scheme, or different www are low-priority technical findings; they do not measure SEO impact.

A canonical to another domain or another page on the same host calls for checking intent, without automatically being an error. One valid canonical with no items to review is a positive result only for the markup observed.

If the parser or body is incomplete, the canonical limit is reached, the HTTP response is not 200, or the scan did not collect enough markup, it cannot conclude that a canonical is missing, unique, or free of items to review.

  1. Missing or invalid with conclusive evidence: correct the markup where it is generated.
  2. Multiple declarations or technical differences: review template and configuration if they do not reflect an intended choice.
  3. Another domain or page: verify the declaration's intent first.

Limits of this check

TrustyRunner cannot confirm Google's chosen URL, deduplication, indexing, or consistency with sitemaps, redirects, and internal links. A cross-domain canonical is not necessarily wrong.

Verify with a new scan

A new scan can review canonical HTML facts in the markup it collects. It cannot confirm a search engine's choice.