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Canonical URL
Definition
Canonical URL
The canonical URL is the main address of a page when multiple URLs can display the same content.
TL;DR
Key Definition
The canonical tag tells engines which version of a page is "the original". It avoids duplicate content penalties and concentrates authority on a single URL.
Importance
Why It Matters
- Avoids duplicate content penalties
- Concentrates SEO authority on one URL
- Simplifies crawling for engines
- Helps AI identify the original source
How It Works
The canonical tag is placed in the HTML head to indicate the preferred URL.
Implementation
<link rel="canonical" href="https://yoursite.com/main-page" /> in the head of each page.
Use Cases
URL parameters, http/https versions, with/without www, pagination, filters.
Metrics
How to Measure It
- Audit of pages without canonical
- Consistency check in Search Console
- Detection of incorrect canonicals
Pitfalls
Common Mistakes
- Canonical pointing to non-existent page
- Incorrect canonical (different page)
- Forgetting canonical on pages with parameters
- Missing self-referencing canonicals
Quick Checklist
Follow these steps to get started.
- Add self-referencing canonical on each page
- Use absolute URLs in canonicals
- Check canonicals on pages with parameters
- Regularly audit with a crawler
Examples
Tracking Parameters
yoursite.com/page and yoursite.com/page?utm_source=facebook should point to the same canonical: yoursite.com/page