Shopify Duplicate URL Checker

Why Shopify creates two URLs for every product

A Shopify product has one handle and one page, but it is reachable at two addresses. The plain one is /products/handle. The second one appears the moment a collection page links to the product, because Shopify builds that link as /collections/collection-handle/products/handle so the product page knows where the shopper came from.

Both addresses return the same page with a 200 status. Add a product to three collections and it has four URLs. A store with 500 products in an average of two collections each serves 1,500 product URLs for 500 products, and every one of the extra 1,000 is a duplicate unless something says otherwise.

What says otherwise is one line in the theme layout, and it comes in two parts:

• canonical_url, a global Liquid object that Shopify's documentation describes as the canonical URL for the current page. On a product page it is the plain /products/handle address, whatever path the page was requested at and whatever ?variant= was appended.
• The link element that prints it. Dawn, Shopify's reference theme, does this on line 8 of layout/theme.liquid: <link rel="canonical" href="{{ canonical_url }}">.

Shopify's help centre lists auto-generated canonical tags among the SEO features every store gets. That is true of the object. The tag itself is the theme's job, which is why a store can lose it without anyone changing a setting, and why the check has to be run against the live HTML rather than the admin.

What a correct canonical looks like for each URL family

Google's canonicalization guidance treats rel=canonical as a strong signal, asks for an absolute URL, and asks the canonical page to carry a self-referencing tag of its own. On Shopify that produces a different right answer for each of the URL families a store serves.

The first three rows are what this tool fetches. The tag and pagination rows are listed because they are the two places people apply the product rule by mistake. Google's pagination guidance says not to use the first page of a sequence as the canonical, and Shopify's default self-referencing canonical on page 2 already follows that.

What breaks the canonical on a Shopify store

The canonical fails in one of three ways, and each one leaves a different fingerprint in the results table. Knowing which you are looking at decides whether the fix is a theme edit, an app setting or a redirect map.

The theme drops the line

A custom theme built from scratch, or a Dawn fork where someone rewrote the head to add a font preload, ships without the canonical link element. Every product row then shows no canonical on both URLs. The fix is one line in layout/theme.liquid, and the Shopify SEO audit guide walks through where it goes.

An app overrides it

SEO apps, translation apps and some page builders inject their own head tags, and a few write a canonical of their own. When theirs is built from the requested URL rather than canonical_url, the collection-path copy canonicalises to itself. That is the self-referencing Warning, and it appears on every product at once.

The target moved

A renamed handle leaves the old /products/ URL redirecting, and any canonical that still points at it is pointing at a redirect. A deleted product leaves it at 404. Both show up as an Error on the plain URL row, which then cascades to every collection path pointing at it.

Two failures that look like canonical problems are something else:

• A blocked fetch. Password-protected stores, and stores whose bot filter answers 403 or 429, produce Warnings that describe this tool being refused. The reason column says so. Nothing about the page is known.
• No product links at all. A theme that renders the product grid in the browser leaves crawlers with an empty collection page, which is a bigger problem than the canonical and is reported as its own note.

What to do with each verdict

The summary counts three verdicts across the sample, and the table shows which URL earned each one. Work them in this order, because an Error on a plain URL is the cause of every Error that points at it.

1. 01

   Paste the store URL, or one collection URL

   The tool fetches /collections/all by default. If your theme hides that collection, or you want to test the collection an app rewrote, paste the collection's own URL instead. A product URL also works and falls back to /collections/all on that store.

2. 02

   Read the Shopify signal first

   The result opens with the header or asset path that identified the store as Shopify. If nothing was found, the paths still get checked, but the verdicts describe whatever the site serves at those addresses rather than Shopify's behaviour.

3. 03

   Check the summary counts

   OK means both URLs of a product resolve to /products/handle, by canonical or by redirect. Warning means a canonical is missing or self-referencing on the collection path. Error means a canonical points at a 404, a redirect or another product, or the plain URL itself redirects.

4. 04

   Open the rows marked Error, then Warning

   Each row shows the status, the canonical and the reason for both URLs. An Error row on the plain URL means every canonical pointing at that product is broken, so fix it before any collection-path row that points at it.

5. 05

   Look at the ?variant= row

   The last row fetches one product with a variant id appended. The canonical should be the plain product URL with the parameter dropped. A self-referencing canonical here means every colour and size on the store is competing with its own product page.

6. 06

   Fix the theme layout, then rerun and crawl the whole store

   The canonical line lives in layout/theme.liquid as link rel=canonical href={{ canonical_url }}. Restore it, remove any app that rewrites it, publish, and run this check again. Then crawl every product rather than twenty, because a sample cannot clear the products it never fetched.

A clean sample means the theme prints the right canonical. It cannot find the one product an app rewrote last week, or a handle renamed without a redirect. Those need every product fetched, which the Shopify canonical and duplicate content guide covers along with the tag, vendor and type pages.

What this tool checks

Frequently asked questions