TECHNICAL · SEO GLOSSARY
Canonical URL
The preferred URL for a page, declared via <link rel="canonical"> to prevent duplicate content from splitting ranking signals.
Definition
A canonical URL is the version of a page Google (and other search engines) should treat as the "original" for indexing and ranking. It is declared using a `<link rel="canonical" href="..." />` tag in the `<head>`. When multiple URLs serve identical or near-identical content, the canonical tag tells crawlers which one to credit.
Why it matters for SEO
Without canonical tags, crawlers may split link equity and ranking signals across multiple URL variants — for example, `example.com/page` vs `example.com/page?ref=twitter` vs `example.com/page/`. The result is that no version ranks as strongly as it would if all signals pointed to one URL. E-commerce sites with filter and sort parameters, and WordPress sites with tag/category archives, are especially vulnerable to unintentional duplicate content from missing or wrong canonicals.
How DeepSEOAnalysis checks this
The audit checks every crawled page for a canonical tag. It flags pages with no canonical as a warning, canonicals pointing to 404 pages as critical, pages where the canonical differs from the URL (redirect chains through the canonical), and cross-domain canonicals that may be misconfigured.
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