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A quick way to understand who this helps, what it solves, and where it connects next.
SEO teams, marketers, developers, and founders reviewing page metadata before publishing.
Quick canonical QA when you have markup in hand and do not need a live URL fetch.
Capture canonical-tag-checker intent with a markup-first browser utility.
Cleanor Labs
These sections explain the job in plain language and set expectations for what the tool should do well.
To check a canonical tag, paste a page's full HTML or just the head markup. The Canonical Tag Checker scans for rel=canonical link elements, extracts the URL value, and reports what it finds. If no canonical is present, multiple canonicals are declared, or the value is relative or otherwise suspicious, the tool flags it as a practical warning.
Canonical mistakes are easy to miss and costly for SEO, because they tell search engines which version of a page to index. Catching a missing or conflicting canonical from the markup — before it reaches production — avoids duplicate-content and indexing problems. The check is paste-first and runs locally in your browser.
Canonical checks usually happen alongside title, meta description, and hreflang QA during on-page reviews. The Canonical Tag Checker keeps that one job focused and fast so it slots cleanly into an existing SEO workflow.
Because it works from pasted markup rather than crawling a live URL, you can validate canonicals on staging pages, drafts, or templated output that is not yet publicly reachable.
Short answers for the questions people usually have before trying a utility like this.
Yes. This tool is free to use with no sign-up, and it runs entirely in your browser.
No. The markup is parsed locally in your browser, so your HTML never leaves your device.
No. The first version is paste-first and browser-only, so you provide the HTML or head markup yourself.
Yes. Relative or suspicious canonical values are surfaced as practical warnings, since canonicals should normally be absolute URLs.
Yes. If a page declares more than one canonical, the checker flags it, since multiple canonicals can confuse search engines.
Every tool on Cleanor is free with no sign-up, no credits, and no limits. Files are processed privately in your browser. Looking for on-device phone cleanup and Premium features? That lives in the Cleanor app.
Paste HTML or head markup, extract canonical tags, and flag missing, multiple, relative, or suspicious canonical values.