Canonical Tag Checker for Launching Websites

What this check catches

A canonical tag tells search engines which URL represents the main version of a page. AI site builders can leave it missing, point it at a preview domain, or emit more than one tag after a template change.

Why it matters before launch

A wrong canonical can send indexing signals to a staging URL or make duplicate homepage variants harder to consolidate. The tag is a signal, so it should match the public URL you intend people and search engines to use.

Common warning signs

• No <link rel="canonical"> in the served HTML
• The canonical still points to a builder or preview domain
• HTTP and HTTPS or www and non-www versions disagree
• More than one canonical tag is present

How to inspect it

1. View the raw response HTML, not only the browser DOM
2. Find every link element whose rel value contains canonical
3. Resolve relative values against the final homepage URL
4. Compare the result with the preferred public domain and redirect behavior

How to fix it

1. Choose one public HTTPS hostname for the site
2. Add one absolute canonical URL in the document head
3. Update the site-builder project domain and SEO settings
4. Redirect alternate homepage variants to the same preferred URL