CloudflareBrowserRenderingCrawler user agent
Operated by Cloudflare
CloudflareBrowserRenderingCrawler is the user agent of the crawl endpoint in Cloudflare's Browser Rendering service.
The CloudflareBrowserRenderingCrawler bot at a glance
- CloudflareBrowserRenderingCrawler is operated by Cloudflare and fetches pages to power a specific product feature.
- The robots.txt token for CloudflareBrowserRenderingCrawler is CloudflareBrowserRenderingCrawler.
- Blocking an AI training crawler has no effect on Google or Bing rankings.
- CloudflareBrowserRenderingCrawler robots.txt support: Yes.
- Recommendation for Generative Engine Optimization (GEO): Your choice.
What is CloudflareBrowserRenderingCrawler?
Cloudflare customers use Browser Rendering to render pages and extract content, often for AI agents and data pipelines.
Cloudflare documents the request headers its browser service sends.
Should you block CloudflareBrowserRenderingCrawler?
Blocking CloudflareBrowserRenderingCrawler is a business decision: it protects your content but can lower how well AI products know your brand.
| Effect on search rankings | Blocking an AI training crawler has no effect on Google or Bing rankings. |
|---|---|
| Effect on AI visibility | Blocking keeps your future pages out of that company's training data, so its models may know less about your brand over time. It does not remove you from that company's AI search, which uses a separate bot. |
| Follows robots.txt | Yes |
| Recommendation | Your choice |
How to block or allow CloudflareBrowserRenderingCrawler
Put the robots.txt rule in the file at the root of every domain and subdomain, for example https://example.com/robots.txt. The token CloudflareBrowserRenderingCrawler is matched case-insensitively.
robots.txt: block
# Block CloudflareBrowserRenderingCrawler
User-agent: CloudflareBrowserRenderingCrawler
Disallow: /robots.txt: allow
# Allow CloudflareBrowserRenderingCrawler
User-agent: CloudflareBrowserRenderingCrawler
Allow: /robots.txt: partial
# Keep CloudflareBrowserRenderingCrawler out of private areas only
User-agent: CloudflareBrowserRenderingCrawler
Disallow: /wp-admin/
Disallow: /cart/
Disallow: /checkout/
Disallow: /my-account/
Allow: /Nginx
# Nginx: return 403 to CloudflareBrowserRenderingCrawler
if ($http_user_agent ~* "(CloudflareBrowserRenderingCrawler)") {
return 403;
}Apache
# Apache .htaccess: return 403 to CloudflareBrowserRenderingCrawler
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} (CloudflareBrowserRenderingCrawler) [NC]
RewriteRule .* - [F,L]Cloudflare WAF
# Cloudflare > Security > WAF > Custom rule, action: Block
(http.user_agent contains "CloudflareBrowserRenderingCrawler")How to verify real CloudflareBrowserRenderingCrawler traffic
Cloudflare publishes no IP list or reverse DNS pattern for CloudflareBrowserRenderingCrawler, so the user agent cannot be verified. Anyone can send the same string. Rate-limit unusual volume instead of trusting the name.
How to find CloudflareBrowserRenderingCrawler in your server logs
Search the web server access log for the token. The command below counts CloudflareBrowserRenderingCrawler requests per URL on Nginx or Apache.
grep -i "CloudflareBrowserRenderingCrawler" access.log | awk '{print $7}' | sort | uniq -c | sort -rn | head -20For a full report per AI bot, upload the log to the AI Log File Analyzer, a free tool by Justin Hà.
CloudflareBrowserRenderingCrawler FAQ
CloudflareBrowserRenderingCrawler uses the robots.txt token "CloudflareBrowserRenderingCrawler". Cloudflare does not publish a full user-agent string, so match the token inside the User-Agent header.
Yes. Cloudflare states that CloudflareBrowserRenderingCrawler follows robots.txt rules written for the "CloudflareBrowserRenderingCrawler" token.
Blocking an AI training crawler has no effect on Google or Bing rankings. Blocking keeps your future pages out of that company's training data, so its models may know less about your brand over time. It does not remove you from that company's AI search, which uses a separate bot.
Add two lines to the robots.txt file at the root of each domain and subdomain: "User-agent: CloudflareBrowserRenderingCrawler" followed by "Disallow: /". The token is case-insensitive. Changes can take up to 24 hours to be picked up.
Not reliably. Cloudflare publishes no IP list or reverse DNS pattern for CloudflareBrowserRenderingCrawler, so anyone can send the same user agent. Rate-limit unusual volume instead of trusting the name.
Search your server access log for "CloudflareBrowserRenderingCrawler", for example with: grep -i "CloudflareBrowserRenderingCrawler" access.log. The AI Log File Analyzer by Justin Hà counts visits per AI bot from an uploaded log file.
Sources: Cloudflare crawler documentation. Last reviewed by Justin Hà.
See which of these bots actually reach your website
The AI Log File Analyzer by Justin Hà counts visits from GPTBot, ClaudeBot, PerplexityBot and other AI crawlers in your server log, for free. The GEO Technical Package sets up robots.txt, llms.txt and crawler access for AI search.
