Crawlability vs Indexability: What's the Difference?

Crawlability is whether a search engine's bots, like Googlebot, can access and navigate a page at all - reachable through links, not blocked by robots.txt, and not stuck behind something the crawler can't process.

Indexability is whether a page that has been successfully crawled is then allowed to be stored in the search engine's index and shown in search results - a separate step that happens after crawling, not a guaranteed consequence of it.

A page can be fully crawlable and still fail to be indexed, which is the distinction that trips people up most often. Common reasons a crawled page never makes it into the index include a noindex tag, a canonical tag pointing to a different URL, thin or duplicate content the search engine judges isn't worth storing, or the page simply never being deemed valuable enough relative to everything else competing for index space. Diagnosing the two requires looking in different places: a crawlability problem shows up in crawl stats and coverage reports as pages the crawler couldn't reach or errored out on, while an indexability problem shows up as pages that were crawled successfully but are explicitly or implicitly excluded from the index anyway. Because indexability depends on crawlability happening first - a page has to be crawled before it can even be considered for indexing - fixing a crawlability problem is the necessary first step, but it's only half the job; a page can clear that bar and still need separate work to actually earn a place in the index.