SurdotlyBot

What is SurdotlyBot?

SurdotlyBot is a specialized web crawler operated by Sur.ly, a service focused on safe browsing and link validation. It functions as a security-oriented crawler that analyzes links across websites to identify potential threats. The bot is developed and maintained by Sur.ly as part of their safe browsing infrastructure, which aims to protect internet users from malicious content.

SurdotlyBot identifies itself in server logs with user agent strings like Mozilla/5.0 (compatible; SurdotlyBot/1.0; +http://sur.ly/bot.html). Sometimes it includes additional system descriptors, but the core identifier remains consistent. The "/1.0" designation indicates a stable release version.

Unlike many other crawlers, SurdotlyBot doesn't execute JavaScript, use cookies, or render pages fully. It operates as a basic HTTP client, focusing specifically on link analysis rather than content indexing or scraping. This specialized approach makes it different from search engine bots that aim to index content comprehensively.

Why is SurdotlyBot crawling my site?

SurdotlyBot visits websites primarily to validate links and assess their safety. If you're seeing this bot in your logs, it's likely examining the hyperlinks on your site to determine if they lead to legitimate destinations or potentially harmful content.

The crawler typically focuses on outbound links from your pages, checking them against Sur.ly's database of known threats. It's not particularly interested in your content itself, but rather in the network of connections your site makes to other domains.

SurdotlyBot's crawling frequency isn't publicly documented, but it appears to use a conservative approach compared to more aggressive crawlers. Your site might see more visits if it frequently updates content or contains many external links.

What is the purpose of SurdotlyBot?

SurdotlyBot supports Sur.ly's safe browsing services by performing preemptive threat detection. Its primary functions include:

1. Malware detection by identifying compromised resources
2. Phishing prevention through validation of domain legitimacy
3. Content authenticity verification by comparing advertised versus actual page content

This security focus explains why SurdotlyBot appears in some security-oriented blocklists despite its relatively non-aggressive crawling profile. The bot serves dual purposes—supporting Sur.ly's safety services while providing data that helps protect users from potentially harmful websites.

For website owners, SurdotlyBot's crawling can indirectly benefit your site's reputation if Sur.ly classifies your links as safe. However, the bot doesn't directly contribute to your search engine visibility or provide analytics data back to you.

How do I block SurdotlyBot?

If you prefer to restrict SurdotlyBot's access to your site, you can use the standard robots.txt protocol, which this crawler respects. To completely block SurdotlyBot from your entire site, add these lines to your robots.txt file:

User-agent: SurdotlyBot
Disallow: /

To block it from specific directories or pages while allowing it to crawl others, you can use more selective directives:

User-agent: SurdotlyBot
Disallow: /private/
Disallow: /members/
Allow: /

Keep in mind that blocking SurdotlyBot may impact how Sur.ly's safety services evaluate links to your site. If your website is legitimate and doesn't contain harmful content, there's generally little reason to block this bot, as its crawling is relatively light and focused on security verification rather than content scraping.

If you need more granular control beyond robots.txt, you could implement user-agent detection at the server level, though this is typically unnecessary for most websites unless you're experiencing excessive crawling that impacts performance.