How to give every product one canonical URL

Give each sellable product one address without parameters, return the same page to every visitor at it, declare it as canonical, and link to exactly that address from everywhere you describe the product. A model can only link an address it can repeat.

The rules

No parameters in the canonical address. Variant selectors, session

tokens and tracking codes make an address a model cannot confidently repeat.

Same page for everyone. No redirects by country or cookie at the

canonical address; if you localise, give each locale its own stable address.

Declare it. A <link rel="canonical"> pointing at itself, and the same

URL in the product's structured data.

Link to it. Collections, comparisons, guides, your blog — every internal

mention of the product points at the canonical address.

Keep it. When the product is discontinued, the address stays and says

so, pointing to the successor.

What goes wrong without them

When a seller's URL appeared in answers we graded, it pointed at the product's own page in 643 cases and at some other page of the same site in 1,445 (study). A stable, declared product address is the precondition for the first number to grow.

The evidence rules — including why a better number afterwards is not yet proof the change caused it — are at /evidence.

How to give every product one canonical URL

The rules

What goes wrong without them

Sources

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