SEO Tools
Canonical Tag Checker
Paste your page HTML to inspect canonical, hreflang, robots, Open Graph, title and description tags all in one place. The tool flags missing canonicals, conflicting robots directives, length issues and Open Graph gaps.
Your input is processed locally in your browser. It is not uploaded to Dueneo.
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How to use
- 1
Paste your HTML
Copy the full page HTML or just the <head>. The tool extracts canonical, hreflang, robots, Open Graph, title and description tags with the browser's DOMParser.
- 2
Read the status banner
The banner summarises errors, warnings and info notes. Errors block rich-result eligibility; warnings should be fixed; info is advisory.
- 3
Review the extracted tags
Every detected tag is listed with its value and character count. Missing fields are highlighted in red so you can spot gaps at a glance.
- 4
Fix issues and re-paste
Each issue lists what to fix. Update your HTML and paste it again — the tool re-validates instantly.
Common use cases
- Audit a page before launch for missing canonical, hreflang or OG tags.
- Catch conflicting robots + canonical directives (e.g. noindex with a canonical).
- Verify title and description lengths are within Google's snippet limits.
- Confirm hreflang pairs include an x-default fallback.
Limitations
- Only tags inside the pasted HTML are checked. Server-rendered or JS-injected tags added after parse time are not detected.
- The tool does not fetch live pages — paste the HTML yourself (View Source in your browser, then copy).
- Schema.org JSON-LD is not checked here — use the Schema Validator tool for structured data.
- Length thresholds (60 for title, 160 for description) are guidelines, not hard limits.