SEO Analysisstarter

Canonical Validator

What it does

Checks canonical tags are correctly implemented across your site. Finds duplicate content, misconfigured canonicals and missing tags.

Misconfigured canonical tags silently destroy your rankings

Canonical tags tell Google which version of a page is the "official" one. Errors in these tags — missing, self-referencing loops, pointing to wrong URLs or conflicting signals — cause Google to ignore your pages or index the wrong version. This is a technical SEO problem invisible to users but can destroy your rankings.

• Missing canonical tags on pages with parameters, filters or sorting
• Canonical tags pointing to wrong URLs or non-existent pages
• Conflicting signals between canonical tag, hreflang and sitemap
• Duplicate content not handled with canonical tags

Validate all canonical tags and fix errors automatically

Canonical Validator crawls your entire site and checks every single canonical tag. You get a complete report of missing tags, misconfigurations, conflicting signals and duplicate content — with auto-generated fixes you can implement directly.

• Complete canonical audit of entire site with error categorization
• Auto-generated fixes: correct canonical tags for each page
• Conflict detection: finds conflicting signals between canonical, hreflang and sitemap
• Duplicate content report: pages without canonical that Google may interpret as duplicates

Features

• Full-site crawl checking canonical tags on all indexed pages
• Error categorization: missing, wrong-pointing, loops, HTTP/HTTPS mismatch
• Automatic generation of correct canonical tags for all pages with errors
• Export of fixes in format adapted for WordPress, Shopify, Next.js and other CMS

How it works

1. Enter website URL for automatic canonical validation
2. Tool crawls all pages and checks canonical tags against best practices
3. Implement the auto-generated fixes to clean up errors

Use cases

• E-commerce stores with thousands of product pages, filters and sorting parameters
• Multilingual websites where canonical and hreflang must work together correctly
• Websites after migration needing validation that canonical tags are updated

Why use Canonical Validator?

Canonical tags are one of the most critical technical SEO elements — and one of the most error-prone. A wrong canonical tag can remove a page from Google's index entirely, and you won't notice until traffic has dropped. Canonical Validator gives you peace of mind by checking every single tag on the site and alerting about problems before they affect rankings.

For e-commerce stores, canonical tags are especially critical. Product pages with filters, sorting and parameters generate hundreds of URL variants for the same content. Without correct canonical tags, Google spends crawl budget indexing all variants instead of important pages — and link authority splits between them.

After site migration, canonical validation is mandatory. Wrong canonical tags are the most common cause of traffic drops after migration. Canonical Validator checks that all tags are updated to new URLs and none point to pages that no longer exist. It's the cheapest insurance against migration disasters.

FAQ

What is a canonical tag?

An HTML tag (rel="canonical") that tells search engines which URL is the preferred version of a page. If you have the same content available at multiple URLs (e.g. with and without parameters), the canonical tag tells Google which one to index.

What happens if canonical tags are missing?

Google must decide on its own which version of the page is "correct". This can lead to the wrong version being indexed, link authority splitting between duplicates, or Google spending crawl budget indexing unnecessary duplicates instead of important pages.

Can wrong canonical tags remove pages from Google?

Yes, if a canonical tag points to another page, Google will treat the original page as a duplicate and remove it from the index. This is a common error after site migration where canonical tags point to old URLs that no longer exist.

How does canonical work with hreflang?

On multilingual sites, canonical and hreflang must work together. Each language version should have a canonical pointing to itself (not to another language version), and hreflang tags pointing to all other language versions. Errors here are extremely common and can destroy international SEO.

How often should I validate canonical tags?

After every major site change (migration, redesign, new sections) and at least quarterly to catch errors that have crept in. E-commerce stores with dynamic URLs should check monthly.

Try Canonical Validator free