Web crawler
A web crawler is an automated program (also called a bot or spider) that systematically browses the web, following links to discover and fetch pages so a search engine can evaluate them for indexing.
What it means
A web crawler is software that browses the web automatically — requesting a page, reading its links, then queuing those links to fetch next. Search engines run crawlers to find content before it can be indexed.
Why it matters for indexing
If a crawler can't reach your pages (a robots.txt block, no inbound links, server errors), they're never fetched — and a page that's never crawled can never be indexed.
How to check it
Check server logs or Search Console's Crawl Stats for crawler activity; use URL Inspection → “Test live URL” to see what Google's crawler fetches and renders.
How FastIndexing helps
Our pre-flight check flags what's blocking crawlers — robots rules, a stray noindex, orphaned URLs — before you spend credits.
Frequently asked questions
What do web crawlers do?
They discover URLs by following links and reading sitemaps, fetch each page's content, and hand it back to the search engine, which then decides whether to index it. Crawling and indexing are separate steps — crawling is just the fetch.
How is a web crawler different from Googlebot?
“Web crawler” is the generic term for any such bot; Googlebot is Google's specific crawler. Bing, Yandex and other engines run their own crawlers too.
Is Googlebot a web crawler?
Yes — Googlebot is Google's web crawler, the bot that fetches pages for Google Search. See the Googlebot entry for specifics.