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What is Crawl frontier?

Verified 5 August 2026

Managing the frontier is most of what a crawler does: deciding what is worth fetching next, when a host may next be contacted, and what to discard.

Prioritisation is where crawl budget is won or lost. Crawling breadth-first spends heavily on regions nobody queries; prioritising by demand spends where there is demand.

Common questions

What is Crawl frontier?

The crawl frontier is the prioritised queue of URLs a crawler intends to fetch, subject to per-host politeness constraints.

How does Crawl frontier work in practice?

Prioritisation is where crawl budget is won or lost. Crawling breadth-first spends heavily on regions nobody queries; prioritising by demand spends where there is demand.

See it working

The free tier is 10,000 requests a month with no card — enough to test any of this against your own queries.