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How do search engines work?

Search engines work in three steps: crawling the web with bots to discover pages, indexing their content in a giant database, and ranking results by relevance and quality when you search — returning answers in milliseconds.

See it in motion.
Watch a 2-minute animated lesson that shows exactly how search engines works.
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Step by step

  • 1Crawlers (bots) follow links to discover and fetch web pages.
  • 2The engine indexes each page's content for fast lookup.
  • 3When you search, it finds matching pages and ranks them by hundreds of signals.
  • 4Relevance, quality, links, and freshness all influence ranking.

Frequently asked questions

What is crawling and indexing?
Crawling is discovering pages via links; indexing is storing and organizing their content so it can be searched instantly.
How do search engines rank pages?
By many signals — relevance to the query, content quality, links from other sites, freshness, and user experience.
What is SEO?
Search Engine Optimization: improving a site so search engines understand it and rank it higher for relevant queries.

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