How Search Actually Works
A plain explanation of what happens between a query and a result.
Before you can do SEO well, you need a clear picture of what Google actually does when someone types a query. This page strips away the jargon and walks through the real pipeline.
The pipeline
When someone searches, the results they see come from a pipeline that started long before their query.
There are three phases: discovery, processing, and serving.
1. Discovery
Google discovers URLs through:
- Links: Googlebot follows links from pages it already knows
- Sitemaps: a sitemap helps discovery but does not guarantee crawling
- Manual submission: URL Inspection can request a crawl
If Google cannot discover a page, everything else is irrelevant.
2. Processing
After a crawl, Google may:
- Parse HTML and extract content, links, and structured data
- Render JavaScript in a separate queue to see the final page
- Decide whether the URL is worth indexing
Crawled does not mean indexed. Indexed does not mean it will rank.
3. Serving
When a user searches, Google:
- Interprets the query and its intent
- Retrieves candidates from the index
- Ranks candidates using relevance, quality, authority, freshness, and other signals
- Assembles the SERP with multiple features, not just blue links
What this means for SEO
Most SEO problems come from a failure in one phase.
- Discovery problems look like pages never getting crawled
- Processing problems look like pages being crawled but excluded from indexing
- Ranking problems look like indexed pages that still do not earn impressions
Takeaway
When something is not working, diagnose the phase first: discovery, processing, or serving. The fix depends on which phase is failing.