Canonical Tags on All Filter URLs
A canonical tag (<link rel="canonical" href="/collections/dresses" />) placed in the <head> of every filtered collection page signals to Google that the base collection URL is the version to index and consolidate link equity toward. When a filter URL like /collections/dresses?color=black&size=medium is crawled, Google sees the canonical pointing back to /collections/dresses and passes equity there instead of splitting it.
In Shopify, you implement this by editing your theme’s collection.liquid or theme.liquid to output the canonical dynamically — always pointing to the handle URL without query parameters when filter tags or parameters are present. Many SEO apps like Plug in SEO or Booster SEO handle this automatically. The critical mistake we see in audits: stores that let each filter URL self-canonicalize (pointing to itself), which provides zero protection. In one audit of a fashion store with 12,000 SKUs, correcting broken self-canonicals on filter pages recovered 34% of crawl budget within 45 days and lifted the root collection pages an average of 6 positions.


























