Canonical URL

The one address you name as the main version of a page that can be reached in several ways. It stops agents treating duplicates as different products. See canonical URLs.

Why it matters

Most online stores can show the same product at several addresses, through filters, tracking tags or sale categories. Without a canonical URL, agents may treat these as different products, split what they know between them or quote an outdated version. Naming one main address keeps agents, and search engines, focused on the right page.

Read the guide Canonical URLs and duplicate pages for AI agents How to stop AI agents reading the same page at many URLs: rel=canonical, parameter and variant URLs, http, https and www redirects, and clean sitemaps. Read it

More terms in understanding pages

• Raw HTML The page exactly as your server sends it, before any JavaScript runs.
• Server-side rendering (SSR) and static generation Ways of building pages so the content is already in the raw HTML, rather than added afterwards by JavaScript.
• Structured data (schema.org, JSON-LD) Machine-readable facts in your page code, such as a product's name, price and stock, written in the shared schema.org vocabulary, usually as JSON-LD.
• XML sitemap A file listing the pages you want found, so crawlers and agents don't depend on following links.
• Alt text A short text description of an image.

Every term, A to Z → · Read the glossary in full →