Crawling

Googlebot fetches pages, respects robots.txt, prioritizes by importance. Continuous — trillions of URLs.

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Crawling

Googlebot fetches pages, respects robots.txt, prioritizes by importance. Continuous — trillions of URLs.

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Parsing + rendering

Modern crawl runs JavaScript. Renders like a browser. Extracts text, links, structured data. Essential for SPAs.

Inverted index

word → list of documents containing it. Compressed heavily. Sharded across thousands of machines. Sub-millisecond term lookup.

Ranking layers

Hundreds of ranking signals: PageRank, freshness, relevance, quality (E-E-A-T). ML models (RankBrain, MUM) blend them.

Query serving

Query → shards contacted in parallel → results merged, ranked, served. All within 200ms budget. Personalization + SafeSearch layered on top.