Canonical tag

Canonical tag

Definition

The canonical tag (<link rel="canonical">) tells search engines which URL is the reference version of a page when several URLs display identical or very similar content. It avoids duplicate content issues and concentrates SEO signals on a single URL.

When to use it

  • Product pages reachable from several categories
  • URLs with parameters (sort, filters, UTM)
  • HTTP / HTTPS or www / non-www variants
  • Printable, AMP or paginated pages
  • Content syndicated on other sites

Best practices

  • Place the tag inside the <head> of every page
  • Use absolute URLs in HTTPS, without unnecessary parameters
  • A page should point to itself (self-canonical) when it is the reference version
  • Keep consistency with the XML sitemap and internal linking
  • Do not combine canonical and noindex on the same page (conflicting signals)