A noindex tag is a directive that tells search engines not to include a specific page in their search index, meaning it should not appear in search results. It is usually implemented as a meta robots tag in the page’s HTML, or as an HTTP response header for non HTML files. Even if a page is accessible and can be crawled, a noindex directive signals that the page is intentionally not meant to be searchable.
Noindex is useful when you want to keep certain pages available to users but out of public search visibility, such as thank you pages, internal search results, staging content, or duplicate variants. To avoid confusion, make sure you apply it only where you truly mean it, and confirm that important pages are not accidentally set to noindex during a site migration or template update. Also remember that blocking a page in robots.txt is not the same as noindex, since blocking can prevent crawlers from seeing the directive at all.