What Is a Web Crawler?
A web crawler (also called a spider or bot) is automated software that systematically browses the web, following links from page to page to discover and process content for a search engine’s index.
How Crawlers Work
Crawlers start from a known set of URLs (often from a sitemap or previously discovered links), download each page’s content, follow the links found on it to discover new pages, and repeat the process continuously. What they find gets processed and, if eligible, added to the search engine’s index for ranking.
Common Examples
Googlebot is the most prominent example, alongside Bingbot for Microsoft Bing, and numerous other crawlers operated by SEO tools (like AhrefsBot), archival services (the Internet Archive’s crawler), and increasingly, AI companies training or grounding language models on web content.
WRITTEN BY
Annabelle Cochrane
MANAGING DIRECTOR & SEO SPECIALIST
Annabelle holds a Bachelor of Business (Marketing) from QUT and works directly with every ALC Consulting client. She’s based on the Sunshine Coast and works with businesses across Australia.
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