By Mehdi HassanWhat is indexing in SEO?
Indexing is how a search engine decides to keep a page. After Googlebot fetches a URL, Google processes it: it renders the content, works out what the page is about, checks whether it duplicates another page and decides whether to store it. Stored pages make up the index that every search draws from.
Indexing is a decision, not a formality. Google can crawl a page and choose not to index it. That's why "indexed pages" is one of the first numbers we check on any site, and why the term sits near the top of our SEO and AEO glossary.
How is indexing different from crawling and ranking?
Crawling, indexing and ranking are three separate stages, and a page can fail at any one of them. The table shows what each stage does and what usually breaks it.
Stage | What happens | Common failure |
|---|---|---|
Crawling | Googlebot discovers and fetches the URL | Blocked by robots.txt, no links pointing to it |
Rendering | Google runs the page's code to see the content | Content only appears after JavaScript runs |
Indexing | Google stores the page and its meaning | Noindex tag, duplicate content, low quality |
Ranking | Indexed pages are ordered for each query | Weak relevance or authority |
AI features depend on the same pipeline. Google's AI Overviews and AI Mode draw on pages in Google's index, and techniques like query fan-out can only retrieve pages that were indexed in the first place.
Why are pages not indexed?
Pages usually aren't indexed because of a technical instruction, a duplication signal or a quality judgment. Search Console's pages report names the reason for each URL, which tells you which fix applies.
- Excluded by noindex. A noindex tag, often left over from staging or a CMS setting, tells Google to skip the page.
- Alternate page with proper canonical tag. The page points to another URL as the main version, so Google indexes that one instead.
- Duplicate without user-selected canonical. Google found near-identical pages and picked one itself.
- Crawled, currently not indexed. Google fetched the page but didn't think it was worth storing yet, often a quality or uniqueness issue.
- Discovered, currently not indexed. Google knows the URL but hasn't crawled it, often because few internal links point to it.
- Blocked by robots.txt or returning errors. The page can't be fetched at all.
The full diagnosis process is in why your pages aren't showing on Google.
What does an indexing problem look like on a real site?
Indexing problems often show up on pages that look fine to people but give Google little reason to store them.
Hypothetical example: a B2B SaaS with dozens of thin feature pages
For example, suppose a SaaS company publishes a separate page for every small feature, each with a short paragraph and a screenshot. In Search Console, most sit in "crawled, currently not indexed".
The team merges them into a handful of outcome-focused pages, each explaining a job the product does, with real detail and clear internal links from the homepage and navigation. The guide to SaaS feature pages shows that structure. Fewer, stronger pages give Google a clear reason to index each one.
The same logic applies to campaign pages. Ad-only pages are often set to noindex on purpose, which is fine, as long as it's a choice. See landing pages for paid ads for when to index them.
