Most canonical checkers only look at one page. This one thinks in clusters and chains.
🔗
Canonical chain detection
Follows one hop further to check whether your canonical target itself canonicalizes somewhere else — a common, hard-to-spot mistake.
📚
Cluster consistency check
Paste a group of related URLs (pagination, filters, sort variants) and see whether they all point to one consolidated target.
🚫
Duplicate tag detection
Flags pages with more than one canonical tag, which search engines may resolve unpredictably.
🔀
Protocol & www mismatch warnings
Catches http vs https and www vs non-www inconsistencies between a page and its canonical target.
🌍
Cross-domain awareness
Flags canonical tags pointing to another domain for a manual check, since this is a legitimate but unusual pattern.
🔒
100% client-side
Checks run from your browser or a CORS proxy chain. Nothing about the URLs you check is stored.
What is a canonical chain and why is it a problem?▾
A canonical chain happens when Page A canonicalizes to Page B, but Page B itself canonicalizes to Page C instead of confirming itself. Search engines generally only follow one hop, so the intended consolidation can fail. Every canonical tag should point directly at the final, self-referencing target.
Can a page have more than one canonical tag?▾
No. Only one canonical tag is valid per page. If multiple are present, search engines may ignore all of them or pick one unpredictably, so this is treated as an error rather than a warning.
What does 'split canonical signals' mean for a page cluster?▾
If several URLs that represent the same content (like paginated or filtered variations) canonicalize to different targets instead of one shared URL, search engines receive conflicting signals about which version to treat as authoritative.
Is a canonical tag pointing to another domain always wrong?▾
No, cross-domain canonical tags are a legitimate pattern for syndicated content, but they're unusual enough that this tool flags them for a manual double-check rather than assuming they're a mistake.
Why does a relative canonical href get flagged?▾
Relative hrefs resolve correctly in most cases, but Google's own guidance recommends absolute URLs to avoid ambiguity, especially on sites with multiple subdomains, protocols, or a base tag that could change how a relative URL resolves.