Canonical Tag Checker
Find and fix duplicate-content canonical issues.
Self-canonicals on every article, automatically.
Sight AI handles canonical tags, internal links, and the dozens of other on-page details so you can focus on what to publish next. 7 free articles to start.
How it works
- 1
Enter any URL
We check the HTML <link rel=canonical>, the HTTP Link header, and the meta robots tag in one pass.
- 2
Spot conflicts
When the HTML and Link header disagree, search engines pick whichever they want. We flag this immediately.
- 3
Resolve the canonical
We resolve relative href values against the page URL so you see the actual canonical Google would honor.
- 4
Sanity-check the destination
Same domain? Same path? Self-referencing? All shown clearly so you can decide if it's right.
A small detail that compounds.
Canonical tags are the difference between two duplicate pages competing with each other and one consolidating all the link equity. Get them wrong and your strongest page can lose to a thin variant.
A surprising number of CMSs ship with broken canonical defaults - staging URLs, www/non-www mismatches, or canonicals pointing to the wrong template. This tool catches all of them.
Every article ships with the right canonical, the first time.
Sight AI generates a self-referencing canonical for every article and respects your domain configuration (www vs apex, http vs https) automatically. No manual templating, no broken edge cases.
Combined with our internal linking and CMS auto-publishing, this means your content stack stays consolidated as you scale to hundreds of articles.
- Auto-generated self-canonicals on every article
- Respects www / apex / https domain configuration
- Auto-detects and warns about cross-template canonical drift
- Fixes legacy canonical issues during the publishing handshake
Common questions.
When should canonical NOT be self-referencing?
Pagination, filter URLs, tracking parameters, and AMP variants should canonical to the canonical version of the page. The default for unique content pages should always be a self-canonical.
What happens if HTML and Link header disagree?
Google has historically prioritized the HTTP header, but the official guidance is that they're both signals and the engine picks whichever seems most accurate. The fix is to make them consistent.
Is canonical a directive or a hint?
It's a hint. Google can ignore your canonical if it disagrees with the page (e.g. completely different content). Conflicting signals are when this happens most.
Can I canonicalize to another domain?
Yes - this is called a cross-domain canonical and is useful for syndicated content. Use sparingly and intentionally.
Get 7 free articles with Sight AI
Sight AI writes long-form, SEO-optimized articles for you and tracks how AI assistants like ChatGPT and Claude see your brand. Create a free account to claim your 7 starter articles.
7 articles, AI visibility tracking, and our full publishing suite included.
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