Canonical URL
The single preferred URL for a piece of content when several URLs serve the same or similar page.
A canonical URL is the version of a page you want search engines to treat as the master when duplicate or near-duplicate URLs exist. You declare it with a rel="canonical" link in the page head (or an HTTP header), pointing to the preferred address.
Duplicates arise constantly: http vs https, www vs non-www, trailing slashes, tracking parameters, and print or pagination variants. Without a canonical signal, Google picks one itself, and it may not choose the one you want. Canonicalization also consolidates ranking signals onto a single URL instead of splitting them.
The important rule for sitemaps: list only canonical URLs. Including non-canonical variants sends mixed signals and wastes crawl budget. A URL's canonical tag should normally point to itself unless it is a genuine duplicate of another page.
Related terms
Stop worrying about your sitemap.
Indexly crawls your site, builds the sitemap, hosts it, and keeps it current — automatically.
Get started free