crawl4ai
Open-source LLM-friendly web scraping and extraction library
About this crawler
crawl4ai is a web crawler identified by the regular-expression pattern crawl4ai in the User-Agent request header. It is categorised as ai-crawler. Use the regex above to detect, log, allow, or block crawl4ai traffic in your web server, CDN edge rules, or robots.txt.
Block-rate · top 25k sites
0.26%
Technical details
- Name
- crawl4ai
- Pattern
crawl4ai- Tags
- ai-crawler
- Reference
- https://github.com/unclecode/crawl4ai
- Added
- 2026/04/26
- Instances
- 1 known sample(s)
Sample User-Agent strings
crawl4ai-adapter/1.0
Block this crawler
robots.txt — disallow crawl4ai:
User-agent: crawl4ai
Disallow: /
Apache .htaccess — return 403:
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} crawl4ai [NC]
RewriteRule .* - [F,L]
Nginx — return 403 inside a server block:
if ($http_user_agent ~* "crawl4ai") {
return 403;
}
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