SEO & Marketing
Canonical Tag Checker
Inspect live canonical tags across public pages and find multiple declarations, insecure targets, repeated destinations and sitemap contradictions.
Preparing the release cockpit…
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Transparent methodology
What the result includes—and what it does not
Built for developers and SEO teams finding canonical regressions across templates or migrations.
Calculation method
- 1Resolve every rel=canonical value against the final page URL and count multiple declarations.
- 2Flag invalid or insecure targets and cross canonical values across the crawl.
- 3Group pages sharing one canonical so template regressions appear as one cause with all affected URLs.
Assumptions and limits
- A missing canonical on a genuinely unique URL is informational, not an automatic release blocker.
- A declared canonical is a signal, not a command; search engines can select another URL.
- The initial release does not fetch every canonical destination as a separate crawl unless it also enters the discovered scope.
Worked example
Product template canonicalized to the home page
Input: Two hundred product URLs whose template publishes the same home-page canonical.
Output: One critical repeated-canonical cause with the home URL as evidence and all product URLs attached.
Primary sources
- Google Search — Crawling and indexingPrimary documentation for crawl access, indexability signals, canonicals, sitemaps, redirects and JavaScript search behavior.
- Google Search — robots.txtExplains that robots.txt primarily controls crawling and is not a guaranteed removal mechanism.
- Google Search — Canonical URLsOfficial guidance for canonical signals and duplicate URL consolidation.
- Sitemaps protocolOpen protocol for sitemap XML, sitemap indexes and loc elements.
How to use it
From public URL to verified release.
- 1Choose the release mission and declare whether the scope should be public.
- 2Keep the page open while respectful batches read public HTML and cross page signals.
- 3Export the evidence, deploy the fix, then load the project to verify the same scope.
Built for trust
Evidence without a false promise.
- No registration or paywall before your result.
- Only public URLs are fetched; HTML is not written into the project.
- Ready to ship describes the checked scope; it never guarantees indexing or ranking.
Frequently asked questions
How can I check canonical tags in bulk?
Run a domain or sitemap crawl. The checker resolves the canonical on every page, reports multiple and insecure values, then groups distinct pages pointing to the same destination.
Does every page need a self-referencing canonical?
Not as an absolute rule. A unique page can be indexed without one, so absence is informational here. Self-referencing canonicals are useful when duplicate URL variants can exist.
Can Google ignore my canonical tag?
Yes. Google documents rel=canonical as one signal among several. Redirects, sitemaps, internal links and page similarity can contradict it, which is why this checker reports cross-signal conflicts.
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