Updated on: 2021-11-23
Referred to as: Canonical URL
Category: General, Technical SEO, On Page SEO

Correct Use:
<link rel="canonical" href="https://stolber.com" />
Description: A canonical URL is considered the original source or the primary content. It is related to paginated content. Where there are several URLs that return essentially the same content the original or primary source should be designated a canonical URL.
This is intended to avoid index bloat and lots of duplicate content.
Our take: Specifying a canonical URL is important. It’s a good way to ensure clean indexing of your site and avoid index bloat and other issues that result in a poor site-wide quality score. It is particularly important for eCommerce sites and other sites with multi-faceted navigation and sites that rely heavily on parameterized dynamic URLs.
Much noise is made about self-referencing canonical URLs, however, we see this as perfectly acceptable. Some SEO tools cite a self-referencing canonical as a warning or information.
Do: Specify a canonical version of your URL.
Make sure the canonical Google has chosen and you have chosen are not in conflict.
Don’t: Leave it to chance and omit the canonical reference on any page.
Tip: Inspect a URL in Google search console (GSC) and look at to see if Google considers it a canonical URL or if it has chosen a different canonical URL before specifically setting a page as a canonical.
Introduced:
Canonical tags were first introduced in 2009. You can read more about it here on Semrush’s beginners guide to canonical URLs.
What Google Says:
Google considers a canonical tag an advanced SEO feature. Read up on Google’s canonical documentation.