Canonical tag

The canonical tag (rel=canonical) is an instruction in a page’s code that tells search engines which URL you consider the official version when several addresses hold identical or very similar content. The same page is often reachable through different URLs — with or without parameters, with or without a trailing slash, mobile versions or shop filters — and that can dilute SEO ✕ SEO (search engine optimization) covers all the measures that get a website to appear higher in Google's unpaid results and thereby attract more visitors. More in the glossary → strength and create duplicate content. By pointing to a canonical URL, you concentrate the ranking signals on it and stop the engine from getting confused or choosing one on its own. It is not an absolute command like noindex, but a strong hint that Google usually respects. It is a basic piece of technical SEO on large or e-commerce ✕ E-commerce is selling products or services online through a web store. It needs a catalog, a cart, secure payments and an SSL certificate. More in the glossary → sites.