How should product variant URLs and canonicals work for Google Shopping?

What it usually looks like on a store

On a real store this shows up as variant links that all open the default option, a canonical tag that still points at a myshopify.com or staging address, or a canonical that sends every product to its collection page. Shopify's ?variant= links preselect correctly when the theme is current.

What Google says

Every variant should have its own URL (path segment or query parameter) that opens the page with that variant preselected: the right image, price and availability, and the ability to add it to the cart. On single-page variant sites, all variants share one canonical URL, usually the base URL with no variant preselected. Variant markup uses ProductGroup with productGroupID (or inProductGroupWithID on each variant), variesBy and hasVariant/isVariantOf, plus a unique ID (sku or gtin) for each variant. In the feed, variants share an item_group_id, each variant needs its own landing page URL, and the link should open the page with the correct variant selected.

The site must have the ability to preselect each variant directly with a distinct URL (using URL query parameters), for example https://www.example.com/winter_coat/size=small&color=green.Google, Product Variant Structured Data (ProductGroup, Product)

Preselecting each variant includes showing the right image, price, and availability, as well as allowing the user to add the variant to the cart.Google, Product Variant Structured Data (ProductGroup, Product)

For single-page sites, there must be only one distinct canonical URL for the overall ProductGroup that all variants belong to.Google, Product Variant Structured Data (ProductGroup, Product)

Each variant must have a unique ID in its corresponding structured data markup (for example, using the sku or gtin properties).Google, Product Variant Structured Data (ProductGroup, Product)

Also seen as: "Item group ID [item_group_id]", "Product variant structured data (ProductGroup, Product)".

How to fix it

Based on Google's help pages, in plain language:

1. Give every variant its own URL (path segment like /t-shirt/green or query parameter like ?color=green) that opens the page with that variant preselected: right image, price, availability and add-to-cart.
2. On single-page variant sites, point rel=canonical on every variant URL at the base product URL with no parameters; use the same URL in internal links, sitemaps and canonicals.
3. Mark up variants with ProductGroup (productGroupID, variesBy, hasVariant) or Product with inProductGroupWithID/isVariantOf, with a unique sku or gtin per variant.
4. In the feed, give every variant the same stable item_group_id and its own link that preselects that variant.
5. Make sure the page details for the selected variant match the feed values (title, color, price, availability, image).

What to check on your website

2 of our checks relate to product variants without their own preselecting urls, and a problem in any one of them can be enough:

• Product canonical URLs: Each product page's canonical URL points at that product on your own domain, and variant URLs (like ?variant=) point at the base product, as Google's variant guidelines describe.
• Product structured data: Each product page has valid Product markup (JSON-LD or microdata) with a name, image and offer.

Requesting a review

No dedicated review; variant price/availability mismatches surface as the normal page-crawl mismatch disapprovals and clear on recrawl.

Questions

Sources

• developers.google.com/search/docs/appearance/structured-data/product-variants
• developers.google.com/search/docs/specialty/ecommerce/designing-a-url-structure-for-ecommerce-sites
• support.google.com/merchants/answer/6324416
• support.google.com/merchants/answer/6324507

Quotes checked against Google's pages. Listvane is an independent tool made by Great Work LLC. It isn't affiliated with, endorsed by or sponsored by Google. Google and Google Merchant Center are trademarks of Google LLC.