Criticalcss.com
What is Criticalcss.com?
About
Criticalcss.com bot crawls websites to generate and validate critical CSS for faster loading times. The service helps developers improve website performance by optimizing above-the-fold content delivery. You can see how often Criticalcss.com visits your website by setting up Dark Visitors Agent Analytics.
Expected Behavior
Developer helpers generally visit websites on direct behalf of a user who is evaluating some feature or attribute. Visits can be one-off or part of a larger crawl.
Type
Detail
| Operated By | Critical CSS |
| Last Updated | 12 hours ago |
Insights
Top Website Robots.txts
Country of Origin
Global Traffic
The percentage of all internet traffic coming from Developer Helpers
Robots.txt
Should I Block Criticalcss.com?
Probably not. Developer helpers are normally used to optimize or find problems with your website.
How Do I Block Criticalcss.com?
You can block Criticalcss.com or limit its access by setting user agent token rules in your website's robots.txt. Set up Dark Visitors Agent Analytics to check whether it's actually following them.
| User Agent String | Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.0 Safari/537.36 Criticalcss.com/2.0.0 |
# In your robots.txt ...
User-agent: Criticalcss.com # https://darkvisitors.com/agents/criticalcss-com
Disallow: /
⚠️ Manual Robots.txt Editing Is Not Scalable
New agents are created every day. We recommend setting up Dark Visitors Automatic Robots.txt if you want to block all agents of this type.