# Canonical tag: definition

> The canonical tag, inserted in a page's via link rel="canonical", tells search engines which URL should be treated as the reference version when several addresses show identical or near-identical content.

- Source canonique : [https://allaux.fr/en/glossaire/canonical](https://allaux.fr/en/glossaire/canonical)
- Langue : EN
- Dernière mise à jour : 2026-09-30

## Why this tag is essential for an online shop

An e-commerce shop naturally generates many URL variants for the same content: filters by size or colour, sorting by price, pagination, tracking parameters added by a campaign. Without a canonical tag, a search engine can index each of these variants separately, spreading relevance across several URLs instead of concentrating it on one.

The canonical tag solves this by explicitly designating the reference URL: every variant points to it, and that is the URL Google favours in its results, even though it keeps crawling the others.

A typical case is a category page displayed with a sort order applied, for example a URL ending in ?order=price-asc: this page should carry a canonical tag pointing to the category URL without the sort parameter, so Google doesn't treat the two as separate, competing pages.

## FAQ

### Can a misconfigured canonical tag make a page disappear from Google?

Yes, if it points to another page by mistake, Google can stop indexing the original page in favour of the one designated as canonical.

### Does every page on a shop need a canonical tag?

Ideally yes, including a self-referencing tag on pages with no variants, which avoids any ambiguity if the URL were unintentionally duplicated later.

### Do PrestaShop and WooCommerce handle the canonical tag automatically?

Both generate it partly by default or through an SEO extension, but custom filters or parameters often need to be checked separately.