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Canonicalisation SEO Best Practices Guide

by Andreas Voniatis Founder. Fractional SEO Consultant.

Canonicalisation issues arise when website content that has more than one possible URL. The most common scenarios are:

  • URLs with tracking parameters and Session IDs
  • Product variations e.g. different colours or other specifications

Best Practice

  • Ensure all internal links within your website point to the primary URL (also known as the canonical), rather than the duplicate URL versions of the same content
  • Never set canonical tags to expired, redirecting, or erroneous content
  • Ensure the canonical includes the full URL address including the domain
  • Never set canonical tags in URLs that are disallowed in the robots.txt file or on pages with the noindex tag.
  • Ensure the HTTP header canonical link matches the one set in the HTML
  • If the user does not need to view the non-canonical URL version of the primary URL: Use 301 redirects in .htaccess server file to permanently redirect the non-canonical version to its primary URL:
    Redirect 301 /non-canonical/ http://artios.io/primary-url
  • If the user does need to view the non-canonical URL version of the primary URL: Use the rel="canonical" tag in web pages inserting the following inside the <head> tag:
    <link rel="canonical" href="http://artios.io/canonical-url">
  • If in doubt, set the rel="canonical" tag to self canonicalise inside all of the primary URL pages. This prevents the crawl and indexing of tracking parameters such as “utm_campaign”, for example
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