Noindex
A directive that tells search engines not to include a page in their search index, removing it from search results.
Definition
The noindex directive instructs search engine crawlers not to include a page in their index, meaning it will not appear in search results. It can be implemented in two ways: as an HTML meta tag (<meta name="robots" content="noindex">) in the page's <head>, or as an HTTP response header (X-Robots-Tag: noindex) in the server response — useful for non-HTML files like PDFs.
Noindex is appropriate for pages that should remain accessible to users but should not appear in search results: admin and login pages, thank-you pages after form submissions, internal search result pages, duplicate or thin content pages, and staging or preview environments. Unlike blocking via robots.txt, noindex allows the crawler to visit the page (and read the directive), but instructs it not to index or rank the page.
A critical conflict to avoid: do not block a URL in robots.txt and also apply noindex. If a URL is blocked by robots.txt, Googlebot cannot crawl it, so it cannot read the noindex directive. The result may be that Google indexes the URL anyway based on external links pointing to it — just without access to the page's actual content. Monitor noindex implementation via Google Search Console's Coverage report, which shows noindex pages under the "Excluded" section.