Cloudflare Browser Run
recommended: observeRenders web pages in headless browsers for Cloudflare customers. Used for browser automation (screenshots, PDF generation, content extraction, etc.) and for AI agents to interact with the web. Used by Cloudflare customers via Workers bindings and REST API. Does not include the /crawl endpoint, which has a separate bot identity (Cloudflare Crawler - Signed Agent).
What it does
The behavior of automated agents generally depends who is using them and what exactly they're using them for. Patterns could vary significantly depending whether the operator is human-guided software (e.g. performance testing), or an autonomous AI agent acting like a human.
How to identify it
User-agent contains any of:
cloudflare-browser-renderingCloudflareMozilla
Example user-agent string:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.107 Safari/537.36 (compatible; +https://developers.cloudflare.com/security-center/)
How to verify it's genuine
Cloudflare Browser Run signs its requests with Web Bot Auth. Botscope verifies the HTTP Message Signature against the operator's published key directory — a forged signature is flagged instantly. View the key directory ↗
robots.txt
Well-behaved crawlers honor robots.txt. To control Cloudflare Browser Run:
Allow full access
User-agent: Cloudflare
Allow: /
Block entirely
User-agent: Cloudflare
Disallow: /
Grey-area scrapers ignore robots.txt. Botscope enforces your policy at the edge or origin regardless —
see how →
FAQ
Should I Block Cloudflare Browser Rendering?
Evaluate case-by-case. Automated agents have diverse uses from legitimate testing to automated attacks. Monitor their behavior and block them if they consume excessive resources, attempt unauthorized actions, or show malicious patterns.
How Do I Block Cloudflare Browser Rendering?
If you want to, you can block or limit Cloudflare Browser Rendering's access by configuring user agent token rules in your robots.txt file. The best way to do this is using Automatic Robots.txt, which update automatically as new agents are discovered. While the vast majority of agents operated by reputable companies honor these robots.txt directives, bad actors may choose to ignore them entirely. In that case, you'll need to implement alternative blocking methods such as firewall rules or server-level restrictions. You can verify whether Cloudflare Browser Rendering is respecting your rules by setting up Agent Analytics to monitor its visits to your website.
Will Blocking Cloudflare Browser Rendering Hurt My SEO?
The SEO impact of blocking automated agents depends on their specific use case. If they're used for legitimate testing or monitoring that helps maintain site quality, blocking could indirectly hurt SEO. However, malicious automated agents might harm your site, so blocking them could protect your search rankings.
Does Cloudflare Browser Rendering Access Private Content?
Automated agents can access whatever content their controlling software directs them to, which could include both public and private content depending on their configuration. If provided with authentication credentials or authorized access, they can interact with private systems just like a human user would. Their scope is entirely dependent on their programming and permissions.
How Can I Tell if Cloudflare Browser Rendering Is Visiting My Website?
Setting up Agent Analytics will give you realtime visibility into Cloudflare Browser Rendering visiting your website, along with hundreds of other AI agents, crawlers, and scrapers. This will also let you measure human traffic to your website coming from AI search and chat LLM platforms like ChatGPT, Perplexity, and Gemini.
Why Is Cloudflare Browser Rendering Visiting My Website?
Cloudflare Browser Rendering accessed your site for purposes that depend on how it's being used. It may have been directed to your site for testing, automation tasks, or by an AI system that identified your content as relevant to its objectives. The specific reason varies based on who is controlling it and what they're trying to accomplish.
How Can I Authenticate Visits From Cloudflare Browser Rendering?
Agent Analytics authenticates agent visits from many agents, letting you know whether each one was actually from that agent, or spoofed by a bad actor. This helps you identify suspicious traffic patterns and make informed decisions about blocking or allowing specific user agents.
References
See Cloudflare Browser Run on your own site
Botscope shows every bot and AI agent hitting your site — and lets you allow, challenge, or block each one. Observe first, enforce when you're ready.
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