A canonical link (also called a canonical tag) is an HTML element that tells search engines which version of a webpage is the preferred (original) version when multiple pages have similar or duplicate content.
It’s written in the page’s <head> section like this:
<link rel="canonical" href="https://www.example.com/preferred-page-url/" />
Why canonical links are important:
- Avoids duplicate content issues
If the same product/page can be accessed through multiple URLs (e.g., with tracking parameters, categories, or filters), search engines might treat them as duplicates. A canonical link tells them which one should be indexed. - Consolidates SEO signals
Backlinks, ranking signals, and authority are combined toward the canonical URL instead of being split between duplicates. - Improves crawl efficiency
Search engines focus on the preferred page instead of crawling many versions of the same content.
Example:
Imagine you have a product page accessible through:
https://www.shop.com/product?color=redhttps://www.shop.com/product?color=bluehttps://www.shop.com/product
Without a canonical link, Google may see these as three separate pages. By adding this:
<link rel="canonical" href="https://www.shop.com/product" />
…you tell Google that /product is the main page to index and rank.
⚡ In platforms like PrestaShop, canonical tags are often automatically added to product and category pages to handle duplicate URLs created by filters, sorting, or pagination.