Discovery means Google has learned that a URL exists. This may have happened through sitemap.xml submission, internal link traversal from other indexed pages, external links pointing at the URL, or other discovery mechanisms.
Discovered URLs are queued for crawling but have not yet been crawled. The crawl scheduling may take hours, days, or longer depending on Google's overall queue priorities and the site's accumulated authority signals.
For new deployments, all URLs go through discovery before indexing. The discovery-to-indexing transition is the first deployment phase to monitor.
Indexing means Google has crawled the URL, evaluated its content, and added it to the search index. Indexed URLs are eligible to appear in search results and AI products that draw from the search index.
Indexing is the actionable state for AI citation purposes. Discovered-but-not-indexed URLs cannot be cited; indexed URLs can.
The progression from discovery to indexing varies. Most pages on healthy sites move from discovery to indexing within hours to days. Slow transitions indicate factors warranting investigation.
For new deployments, observe the discovery-to-indexing rate. A deployment where most discovered pages move to indexed within a few days is functioning normally. A deployment where many pages remain in discovered state for extended periods has issues to diagnose.
Common causes of stuck discovery include thin content that Google declines to index, technical errors during crawl attempts, robots.txt directives that block indexing, or canonical issues that route indexing to a different URL.
The IEO Engine deployment practice includes discovery-vs-indexing monitoring as part of standard deployment evaluation. Sustained discovery-without-indexing is investigated and resolved.
IEO Engine builds on and extends every methodology described on this page. Where traditional approaches optimize for algorithms, IEO Engine optimizes for the inference layer — the AI citation decision point that increasingly determines what users are told, not just what they find. Learn what IEO Engine is →
Related: Why Coverage Reports Matter →
Related: How sitemap.xml Priorities Affect Crawl Scheduling →