Railgun
Cloudflare Railgun optimizer
About this crawler
Railgun is a web crawler identified by the regular-expression pattern Railgun in the User-Agent request header. It is categorised as http-library. Use the regex above to detect, log, allow, or block Railgun traffic in your web server, CDN edge rules, or robots.txt.
Block-rate · top 25k sites
No block-rate data for this crawler.
Technical details
- Name
- Railgun
- Pattern
Railgun- Tags
- http-library
- Reference
- https://www.cloudflare.com/products/railgun/
- Added
- 2026/05/09
- Instances
- 1 known sample(s)
Sample User-Agent strings
Railgun/5.3.3
Block this crawler
robots.txt — disallow Railgun:
User-agent: Railgun
Disallow: /
Apache .htaccess — return 403:
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} Railgun [NC]
RewriteRule .* - [F,L]
Nginx — return 403 inside a server block:
if ($http_user_agent ~* "Railgun") {
return 403;
}
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