What is Canonical URL?

The canonical tag (link rel="canonical" href="...") consolidates SEO signals when the same content is accessible via multiple URLs. Common scenarios include HTTP vs HTTPS, www vs non-www, trailing slashes, URL parameters (sorting, pagination, tracking), and syndicated content. Without canonical tags, search engines may split ranking signals across duplicates or choose the wrong version to index. Self-referencing canonicals (pointing to the current URL) are best practice for all pages. Canonical URLs should be absolute (not relative), consistent with the sitemap, and match the URL returned by redirects. They are a hint, not a directive — search engines may override them.