🏷️ Canonical Tag Checker
Check canonical URLs — detect missing tags, mismatches, and canonicalization issues
What Is the Canonical Tag Checker?
Canonical Tag Checker fetches any webpage and inspects its <link rel="canonical"> tag and HTTP Link headers. It detects missing canonicals, self-referencing patterns, URL mismatches, and warns about common canonicalization mistakes that hurt SEO.
Key Features
- Canonical Detection: Finds the canonical URL in both HTML tags and HTTP headers.
- Self-Referencing Check: Verifies whether the canonical points to the same page.
- Warnings: Alerts for missing canonicals, relative URLs, and multiple canonical tags.
- HTTP Header Support: Also checks the Link header for canonical directives.
📋 When to Use
Use to audit canonical tags after migrations, verify proper cross-domain canonicals, debug duplicate content issues, check that paginated pages point to the correct canonical, and ensure parameter-based URLs consolidate properly.
⚙️ How It Works
The tool fetches the page HTML via the ToolStand proxy, parses it for <link rel="canonical"> elements, and also checks the HTTP Link response header. It compares the canonical against the requested URL and generates warnings for common issues.
How to Use the Canonical Tag Checker
- Enter a URL you want to check.
- Click Check Canonical to fetch and analyze.
- Review the canonical URL found in the page.
- Check the warnings for any issues detected.
Frequently Asked Questions
What is a canonical tag?
A <link rel="canonical"> tag that tells search engines which URL is the preferred version of a page.
Why check canonical tags?
Incorrect canonicals cause indexing of wrong URLs and split ranking signals across duplicates.
What is self-referencing canonical?
When the canonical URL matches the page URL — Google recommends this as best practice.
What if there's no canonical?
Google chooses its own, which may not match your intent. Add a self-referencing canonical.
Is it free?
Yes, completely free. No signup, no limits.