Using the “canonical” Tag on Ecommerce Websites

Phil Rothwell, CEO of EcomEvolveMost people who can read and write can optimise a web page using little more than common sense. However, a bit of technical know-how can make the difference between high ranking or no ranking.
For online retailers, one technical insight that is important to understand is the “canonical” tag, which you can find in the “header” section at the top of almost all well-optimised web pages.
The one on our homepage looks like this:
<link rel="canonical" href="" />
And, if you are wondering, the “/” at the end indicates that this is a self-closing tag.

Why is the canonical tag important?

The canonical tag plays an important role in ecommerce, because it is used to avoid the damage that duplicate pages can do to you search engine rankings. Duplicate pages are a necessary evil for most online retailers:

  • Necessary, because when you use a hierarchical content structure you often need to create duplicate product and section pages
  • Evil because when you create pages with duplicate content, search engines will assume you want them all to be listed. The result is that instead of having a single listing that is more highly ranked, you end up with multiple listings that have a lower ranking

I could go on, but that is probably sufficient for now.

What does the canonical tag do?

The canonical tag is used to tell search engines where the original version of a page is located. So, if the page being viewed is a copy of another page, then the canonical tag will tell the search engine where the original page is located.

How are canonical tags used in Sellerdeck?

The most recent versions of Sellerdeck insert a canonical tag on every page on the website. There are two bits of functionality that are useful to be aware of.

If you create a duplicate product, the html page it creates for the duplicate includes a canonical tag that points to the original product.

Where you use pagination on larger sections, there is an option to create an additional section page that lists all the products in the paginated sections. When this is selected, a canonical tag is added to the paginated pages pointing at this additional section page.

How are canonical tags used in Shopify?

Shopify works in a similar way. By default, product details  are published directly as:

Or can be organised onto collections:

Canonical tags are used to on the collections pages to inform search engines that the version of page in the collection is a copy of the original.

For instance, a tag like this:

<link rel="canonical" href="" />

Would be inserted on the page to inform Google that the page was a copy of the original product page.

Are there any pitfalls to avoid when using canonical tags?

Yes, look out for the following points:

  • Do not use a canonical tag when the content of the duplicate page is substantially different to the original.
  • We may think they are the same, but as far as Google is concerned the following pages are different:


You need to use the same domain name consistently across your website. This has been a serious problem for many online retailers when they have installed security certificates on their websites.

Further reading at:

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