Canonical URL

Technical explanation

Site owners signal canonical preference through redirects, rel="canonical" annotations, sitemap inclusion, and consistent internal linking. Search engines combine these signals with their own assessment and may select a different canonical when signals conflict.

Business relevance

Canonicalisation consolidates indexing signals, reduces duplicate-content ambiguity, and helps crawlers focus on the intended public URL.

Implementation example

Filtered versions of a directory point to the clean primary page with rel="canonical", while internal links and the sitemap use only the canonical address.

Limitations and common misconceptions

A canonical annotation is a hint, not an instruction. It should not point to unrelated content, replace redirects for moved pages, or conflict with noindex, sitemap, and internal-link signals.

Topics

Sources