What is W3C_CSS_Validator?
W3C_CSS_Validator is listed as a developer tool. Use this crawler profile to identify user-agent tokens, operator signals, platform hints, and recommended handling.
W3C_CSS_Validator
Developer tool
- Version
- 2.0
- First seen
- Sep 17, 2025
- Confidence
- Known user-agent token
Crawler tags
Directory facts
- AI model training
- Not listed as training
- Acts on behalf of user
- Yes, user-triggered
- Obeys directives
- Yes, listed as obeying robots.txt
What is W3C_CSS_Validator?
W3C_CSS_Validator is listed as a developer tool. W3C_CSS_Validator is likely a user-triggered fetcher that retrieves a page after someone asks for, previews, or opens a URL.
W3C_CSS_Validator matched a known crawler token in the user-agent string, but this page alone does not prove IP ownership.
How to identify W3C_CSS_Validator in logs
Search server logs for W3C_CSS_Validator. Matching those tokens is useful for discovery, but IP verification is still recommended before trusting the identity.
Jigsaw/2.3.0 W3C_CSS_Validator_JFouffa/2.0 (See http://validator.w3.org/services)
Use this as a web-crawler lookup reference for identifying how this user-agent presents itself in server logs. After you identify crawler traffic, run the WebMCP Compatibility Checker to confirm whether AI crawlers and agents can understand your site.
User-agent signals
- Product tokens
- Jigsaw/2.3.0, W3C_CSS_Validator_JFouffa/2.0, See
- Documentation
- http://validator.w3.org/services
- Contact
- None found
- Platform
- Unknown · Unknown
- Browser profile
- Unknown · Unknown
- Browser-like UA
- No
- HTTP library
- Unknown
- Spoof risk
- Medium
Questions answered by this crawler profile
What is W3C_CSS_Validator?
W3C_CSS_Validator is listed as a developer tool. W3C_CSS_Validator is likely a user-triggered fetcher that retrieves a page after someone asks for, previews, or opens a URL.
Does W3C_CSS_Validator train AI models?
W3C_CSS_Validator is not listed as being used to train AI or LLM systems.
Is W3C_CSS_Validator user-triggered?
W3C_CSS_Validator is listed as being triggered by a real user action.
How do I identify W3C_CSS_Validator in logs?
Search server logs for W3C_CSS_Validator. Matching those tokens is useful for discovery, but IP verification is still recommended before trusting the identity.
Does W3C_CSS_Validator respect robots.txt?
This directory entry lists the crawler as obeying robots.txt directives. Confirm behavior in your logs before relying on user-agent strings alone.