---
name: thedaviddias/canonical-url
source: https://app.decimal.ai/s/thedaviddias-canonical-url@1/SKILL.md
source_sha256: 05006e0d5930
---

# Set canonical URLs for all pages

Duplicate content from URL parameters, www vs non-www, or pagination dilutes ranking signals—canonical tags consolidate these signals to the preferred URL.

## Quick Reference

- Canonical URLs tell search engines which version of a page to index
- Prevents duplicate content penalties from URL variations
- Use absolute URLs including protocol and domain
- Self-referencing canonicals are a best practice

## Check

Verify that this page has a canonical URL tag and that it points to the correct preferred version.

## Fix

Add or correct the canonical URL tag in the head section to prevent duplicate content issues.

## Explain

Explain how canonical URLs help search engines understand the preferred version of duplicate or similar pages.

## Code Review

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

---

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

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