Canonical URL

A canonical URL is the address you declare, in a tag in the page's code, as the primary version of a page that exists at more than one URL. Online stores generate duplicates constantly and legitimately: the same product reachable through three collection paths, with and without tracking parameters, in several colour variants, sorted different ways. Without a canonical, search engines either split the page's credit across the copies or choose one themselves — sometimes the tracking-parameter version, sometimes a variant you'd never have picked.

Most platforms set canonicals correctly by default, pointing every path to the clean product URL. The damage comes from themes and apps that override the tag, from imported catalogues that carry their own, and from the rare but serious misconfiguration where every product's canonical points at the home page or a collection — which quietly removes the entire catalogue from the index. Search Console flags the symptoms as "Duplicate" statuses and "Google chose different canonical than user." Because the tag lives in the template, the fix is almost always one setting rather than a page-by-page job.