---
name: thedaviddias/canonical-header
source: https://app.decimal.ai/s/thedaviddias-canonical-header@1/SKILL.md
source_sha256: 0ed65706379f
---

# Sync HTML canonical tags and Link headers

Conflicting canonical-url signals can lead search engines to ignore both declarations, potentially causing duplicate content issues and incorrect indexing.

## Quick Reference

- Ensure the `rel="canonical"` tag in your HTML matches the `Link` canonical-url header if both are used
- Avoid sending conflicting signals to search engines about the primary version of a page
- Maintain consistency across all methods of declaring your canonical URL

## Check

Compare the HTML canonical tag with the HTTP Link header to ensure they point to the exact same URL.

## Fix

Update either the HTML tag or the HTTP header so that they provide a consistent canonical URL signal.

## Explain

Explain the risks of sending conflicting technical SEO signals to search engine crawlers.

## Code Review

Review metadata generation, rendered HTML, structured data, and response headers related to Sync HTML canonical tags and Link headers. Flag exact routes or templates where search-facing output violates the rule, and describe how to verify the final page output.

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For full implementation details, code examples, and framework-specific guidance,
see `references/rule.md`.

Rule page: https://frontendchecklist.io/en/rules/seo/canonical-header