Canonical Tag Checker
Verify canonical URLs to prevent duplicate content issues
Note: Canonical tags tell search engines which version of a URL to index. Proper implementation prevents duplicate content issues.
Canonical Tag Guide
What is a Canonical Tag?
A canonical tag (<link rel="canonical">) tells search engines which version of a URL is the preferred one to index. This prevents duplicate content issues when the same content is accessible via multiple URLs.
When to Use
- ✓ URL parameters (sorting, filtering)
- ✓ HTTP vs HTTPS versions
- ✓ WWW vs non-WWW versions
- ✓ Mobile vs desktop URLs
- ✓ Syndicated or scraped content
Implementation Example
<head>
<link rel="canonical" href="https://example.com/page" />
</head>
Common Mistakes
- ✗ Multiple canonical tags on one page
- ✗ Canonical pointing to 404 page
- ✗ Canonical in body instead of head
- ✗ Relative URLs instead of absolute
- ✗ Canonical chains (A→B→C)
Canonical Tag Best Practices
| Practice | Recommendation |
|---|---|
| Self-Referencing | Every page should have a canonical pointing to itself |
| Absolute URLs | Always use full absolute URLs (https://...) |
| One Per Page | Only one canonical tag per page |
| In <head> | Place canonical in the head section only |
| HTTPS Preferred | Canonical should use HTTPS if available |
| Consistent | Align with og:url, twitter:url, and sitemap |