In one sentence
A canonical URL is the main version of a page that you tell search engines to count when the same product shows up at several addresses, so ranking signals aren't split across duplicates.
Why online stores end up with duplicate URLs
Stores create duplicates without trying. The same product can load at its own address, inside every collection it belongs to, with a variant picked, with tracking tags added, or with the list sorted a different way.
To a crawler, each address can look like a separate page with the same content. Without a canonical, search engines have to guess which one to show, and links and signals get split across the copies.
How a canonical tag works
A canonical tag is one line in a page's code, <link rel="canonical" href="...">, that points to the version you want counted. Every duplicate points to the same main URL.
Google treats the tag as a strong hint, not a command. If your internal links, sitemap and redirects all point to the same main URL, Google is far more likely to follow it.
Canonical tag vs. 301 redirect: when to use which
How to check canonical URLs on your store
- Open a product page, view the page source and search for "canonical". Confirm it points to the clean product URL.
- Repeat from a collection page link and a variant link. They should point to the same place.
- In Google Search Console, use URL Inspection to compare the canonical you declared with the one Google chose.
- Fix any mismatch at the source: internal links, sitemap or theme code.
Canonical URL FAQs
Does Shopify set canonical URLs automatically?
Yes. Shopify themes add a canonical tag, and product URLs reached through a collection point back to the main /products/ URL. Custom themes and apps can break this, so spot-check a few pages.
Should product variants have their own canonical URL?
Usually not. Variant links should point to the main product page, so all signals land in one place. Give a variant its own page only if shoppers search for it as a separate product.
Can a canonical URL point to another website?
Yes. If you publish the same article on your blog and on a partner site, the copy can point to the original. Search engines then credit the original page.
About the author
Jenn Starr, Co-founder, Selix
Jenn has spent 20+ years helping SaaS startups build their marketing and implementation playbooks. She has bootstrapped three marketing agencies and is a 500 Startups alum. At Selix, she leads the work of getting ecommerce brands named in AI answers.