canonical-tag-discipline

name	canonical-tag-discipline
description	Use when duplicates or near-duplicates exist. Canonical tells Google which URL is the master version.

Canonical Tag Discipline

Canonical = signal of master URL. Use to: consolidate near-duplicates, declare HTTPS over HTTP, www over non-www, mobile→desktop.

When canonical is needed

1. Mobile + desktop versions (canonical to desktop URL)
2. HTTPS + HTTP (canonical to HTTPS)
3. www + non-www (canonical to chosen version)
4. URL parameter variants (e.g., ?utm=...)
5. Print version + main version
6. Multiple URLs serving same content (uppercase/lowercase)
7. Pagination (rel=next + canonical to first page in some cases)

Implementation

<link rel='canonical' href='https://cardprepai.com/grading' />

Always:

• Absolute URL (not relative)
• Single canonical per page
• Self-canonical OK (canonical = current URL)

Common mistakes

1. Multiple canonicals (Google picks one randomly)
2. Canonical pointing to non-existent URL (404)
3. Canonical pointing to redirected URL (chain)
4. Canonical on every page pointing to homepage (mass de-indexing risk)
5. Missing canonical on duplicate-content pages

Where this fits in the X3 empire

Canonical hygiene for CardPrepAI.