AI crawler · Google · Search engine
Googlebot: what it is, its user agent, and how to block it
Googlebot is Google's search crawler. Google's main crawler for Search, including Discover, AI Overviews and AI Mode, plus Images, Video and News. In our 13 October 2026 study, 49 of 2,332 live top sites with readable robots.txt rules (2.1%) disallow Googlebot. Part of the AI crawler list.
What Googlebot does
Operator: Google. Job: Search engine. Obeys robots.txt.
“Google's common crawlers are used to find information for building Google's search indexes, perform other product specific crawls, and for analysis. They always obey robots.txt rules when crawling automatically.”
Googlebot user agent
robots.txt token: Googlebot (matched case-insensitively).
Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/W.X.Y.Z Mobile Safari/537.36 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Googlebot/2.1; +http://www.google.com/bot.html) Chrome/W.X.Y.Z Safari/537.36Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)Googlebot/2.1 (+http://www.google.com/bot.html)Google writes W.X.Y.Z where the Chrome version goes.
robots.txt: allow or block Googlebot
Allow
User-agent: Googlebot
Allow: /Block
User-agent: Googlebot
Disallow: /Affects AI answers and citations. Blocking it removes your pages from Google's search index, and from the AI answers Google builds on that index.
Once a group names Googlebot, it ignores your User-agent: * rules, so copy any paths you still want blocked into it.
How many top sites block Googlebot
Disallow Googlebot in robots.txt
2.1%
49 of 2,332 sites
In our 13 October 2026 study, 49 of 2,332 live top sites with readable robots.txt rules (2.1%) disallow Googlebot.
Sample: Tranco top 5,000, tested once on 13 October 2026 from one Indian fixed-line connection. The robots.txt share counts live sites (home page 2xx) whose rules we could read, as on the AI visibility hub. Method and CSV in the study.
Check your own site
The AI crawler checker reads your robots.txt the way Googlebot does and tests what your firewall returns. To write the rules, use the AI robots.txt generator.
Check your page: free, about 20 seconds, no sign-in
What it checks
- robots.txt for Googlebot
- Finds the group Googlebot obeys under RFC 9309 and the rule that decides your page.
- What your CDN lets through
- Requests the page as OAI-SearchBot, PerplexityBot and Claude-SearchBot and compares the answers with a browser request.
- Content without JavaScript
- AI crawlers don't run JavaScript. The audit checks how much of the page is in the raw HTML.
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Questions
What is Googlebot?+
Googlebot is Google's search crawler. Google's main crawler for Search, including Discover, AI Overviews and AI Mode, plus Images, Video and News.
What is Googlebot's user agent?+
Google documents it as: Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/W.X.Y.Z Mobile Safari/537.36 (compatible; Googlebot/2.1; +http://www.google.com/bot.html). Match on the token Googlebot, since version numbers change.
How do I block Googlebot?+
Add "User-agent: Googlebot" followed by "Disallow: /" to your robots.txt. Obeys robots.txt, per Google.
Does blocking Googlebot affect AI search citations?+
Blocking it removes your pages from Google's search index, and from the AI answers Google builds on that index.
How many websites block Googlebot?+
In our 13 October 2026 study, 49 of 2,332 live top sites with readable robots.txt rules (2.1%) disallow Googlebot.