How does Lemwatch validate canonical URLs?

Lemwatch checks every crawled page for a rel=canonical tag, verifies it resolves to a 200, and flags self-referencing errors or canonical loops.

Quick answer

On each SEO crawl we look for <link rel="canonical"> on every page, follow it, and confirm the target returns 200. We flag missing canonicals, self-referencing typos, canonical loops, and canonicals that 301/404.

What we detect

• Missing canonical on indexable pages
• Canonical pointing to a 404 or 500
• Canonical chain (A → B → C)
• Canonical to a noindex page
• Cross-origin canonical without hreflang

Where to find it in Lemwatch

Site → SEO → Canonical.

FAQ

What about paginated pages?

We treat rel=prev/next as valid canonical alternates.

Related

• Hreflang monitoring
• SEO monitoring overview