Skip to content
Directory/Categories/Other/Critical CSS Bot
CR

Critical CSS Bot

GoodBotVerifiedBOT

We operate a SASS for website optimisations, we have thousands of customers. Some of them use Cloudflare but I don't have access to any exact list. Operated by Critical CSS.

GoodBot
Assessment
Other
Category
BOT
Kind
1
Data sources
AI-generated summary, drawn from Cloudflare, operator docs, and community data

What is Critical CSS Bot?

Critical CSS Bot is a web crawler operated by Critical CSS. We operate a SASS for website optimisations, we have thousands of customers. Some of them use Cloudflare but I don't have access to any exact list.

Helpful — Verified, safe crawler. Respects robots.txt and provides operator documentation.

Identification

Bot name
Critical CSS Bot
Operator
Critical CSS
Category
Other
Kind
BOT
Verification
Verified bot
Cloudflare slug
criticalcssbot
User-agent patterns
Criticalcss.com/
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
Main use cases
Web crawlingData collection

Why it crawls your site

Critical CSS Bot crawls websites to collect and process web content. It is operated by Critical CSS as part of their web crawling infrastructure. If you see this bot in your server logs, it is a verified crawler and generally safe.

Block or allow Critical CSS Bot

Block it

Add a Disallow rule for Criticalcss.com/ in your robots.txt file. You can also block at the server level using your web server configuration or CDN firewall rules to filter requests matching the user-agent string.

# Block Critical CSS Bot from crawling your entire site
User-agent: Criticalcss.com/
Disallow: /

# Allow Critical CSS Bot full access
User-agent: Criticalcss.com/
Allow: /
Allow & verify

Ensure your robots.txt allows Criticalcss.com/. Verify requests are genuine by checking the user-agent string and referring to Critical CSS's documentation.

Traffic & trends

Cloudflare Radar traffic

No Cloudflare traffic data available.

Google Trends interest

Loading trend data…

Data sources

This profile is compiled from the following sources.

CloudflareRadar
Last updated July 26, 2026