Self-referencing canonicals are something every company and webmaster should implement on their websites, yet they are often missing during our daily SEO checks at Brath. But what does the term actually mean, and why should self-referencing canonicals be implemented?
To answer these questions, we believe it’s best to start at the right end and first ensure that you, the reader, have a basic understanding of canonicals in general.
Let’s therefore take a closer look at canonicals from a general perspective, as well as how a “standard canonical” and a “self-referencing canonical” differ from each other.
The difference between a “standard canonical” and a “self-referencing canonical”
Standard canonicals
A canonical is an HTML tag whose task is to tell search engines which specific URL on a site represents the main version of a page, i.e., the canonical version.
Canonical tags can therefore be used to resolve issues related to identical and duplicate content, by pointing to the original source from pages that exist in multiple variations on your site. This also makes it clear to Google and other search engines which landing page you intend to rank in their respective search results.
There are many reasons why duplicates of pages may appear on a site and why they sometimes need to be kept rather than redirected (which would otherwise be recommended). Most often, this is due to factors related to improved user experience, for example when an extensive product feed needs to be paginated, i.e., divided into multiple pages.
In the example image below, you can see how a canonical tag should be set up when paginating a product category. In this case, the second page in the sequence points to the first, but the same implementation also applies to pages 3, 4, and so on.
Self-referencing canonicals
A self-referencing canonical takes things a step further, as it not only points to a canonical URL from other pages but also includes the same information within the page’s own code.
In the example image below, you can see how a self-referencing canonical tag should be set up for a product category, but the same implementation also applies to a site’s index page, as well as main and subcategories, and more.
The reason for this measure is to further clarify which page should be indexed and subsequently ranked, something Google’s own spokesperson John Mueller himself recommends in the YouTube clip below.
Self-referencing canonicals are also a good protection against scraping
Another benefit of self-referencing canonicals is that they can also serve as effective protection in cases where someone chooses to scrape your code (copy it), with the intent of creating a clone of your entire site or specific pages on another domain.
There is a high likelihood that the canonical tags will remain intact, in which case they will point back to your site and clearly signal to Google and other search engines the original source of all the content.
Good luck with your implementation!
Martin Ek
SEO specialist
Martin works as an SEO specialist at our Örnsköldsvik office