Canonical URLs

Canonical URLs are the designated versions of a webpage that search engines treat as the authoritative source when multiple URLs contain identical or very similar content. Specified using the rel="canonical" link element, canonical URLs prevent duplicate content issues that can weaken rankings and cause confusion for crawlers.

Typical use cases for canonicalization include handling differences between HTTP and HTTPS, www and non-www domains, pages with tracking or filter parameters, desktop and mobile versions, or content available under multiple URL paths. By pointing to the canonical version, you signal to search engines which page should carry ranking authority, consolidating signals and avoiding duplicate content penalties.

For GEO and AI-driven search, proper canonicalization also matters. AI systems may encounter various page versions while crawling or citing sources. Clear canonical signals ensure the AI references the correct version, increasing the likelihood of proper attribution and consistent brand visibility in generated responses.

Best practices for implementing canonical URLs include applying them consistently across the site, choosing the most appropriate version of each page (typically HTTPS on the preferred domain), using absolute URLs rather than relative paths, ensuring the chosen page is accessible to both crawlers and users, and regularly reviewing implementation. Even for unique content, self-referencing canonical tags are recommended to clearly indicate the authoritative URL.