Claude-User
Anthropic Claude user web crawler bot
About this crawler
Claude-User is a web crawler identified by the regular-expression pattern Claude-User in the User-Agent request header. It is categorised as ai-fetcher. Use the regex above to detect, log, allow, or block Claude-User traffic in your web server, CDN edge rules, or robots.txt.
Block-rate · top 25k sites
1.9%
Technical details
- Name
- Claude-User
- Pattern
Claude-User- Tags
- ai-fetcher
- Reference
- https://useragents.io/uas/mozilla-5-0-applewebkit-537-36-khtml-like-gecko-compatible-claudebot-1-0-supportanthropic-com_954fa13a8e1e46d8267fb56e2d48100e
- Added
- 2026/04/07
- rDNS suffixes
.anthropic.com- Instances
- 2 known sample(s)
rDNS verification (FCrDNS)
Verify a request is genuinely Claude-User with forward-confirmed reverse DNS: the client IP's PTR record must end in one of the suffixes below and a forward A/AAAA lookup of that hostname must return the same IP. UA strings alone are spoofable; FCrDNS is not.
.anthropic.com
Sample User-Agent strings
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Claude-User/1.0; [email protected])
Claude-User (claude-code/2.1.86; +https://support.anthropic.com/)
Block this crawler
robots.txt — disallow Claude-User:
User-agent: Claude-User
Disallow: /
Apache .htaccess — return 403:
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} Claude-User [NC]
RewriteRule .* - [F,L]
Nginx — return 403 inside a server block:
if ($http_user_agent ~* "Claude-User") {
return 403;
}
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