Noindex

Noindex is a directive placed in a page's HTML head or returned as an HTTP response header that tells search engine crawlers to discover and crawl the page, but exclude it from the search index. When a page is noindexed, it won't appear in search results, though links on it can still pass authority and crawlers will still process it.

SEOs use noindex to prevent low-value or duplicate content—internal search results, staging environments, thank-you pages, or canonically inferior variations—from competing in the index without blocking crawl flow or link equity. It's gentler than robots.txt blocking, which prevents crawling entirely, and more appropriate than canonical tags when content shouldn't be indexed at all.

In practice, noindex is temporary or permanent depending on intent: temporary when testing or staging content, permanent when protecting thin pages or session-specific results. Misapplying noindex—say, to pages meant to rank—is a common SEO mistake; so is leaving it on by accident during migration or redesign. Search engines respect noindex, but there can be a lag between deployment and removal from the index.