Verified Bots Directory

Directory / SEO tools

Validator.nu (W3C Nu HTML Checker)

Verifiable

The fetcher behind the Nu HTML Checker, the W3C validation service that checks a user-submitted URL against current HTML conformance rules. W3C's validation services page lists its user agent and states that all W3C validator traffic comes from one published IPv4 address and one IPv6 prefix.

Operated by World Wide Web Consortium (W3C) · Official documentation

User agents

Patterns this directory matches, with real observed strings.

  • regexValidator\.nu/
  • observedValidator.nu/LV

How to verify

Documented static ranges: 52.22.66.203/32, 2600:1f18:7d7a:2700::/56

IP ranges (2)

Refreshed daily from the operator's feed. Also available as /data/ips/w3c-validator-nu.ips and /data/bots/w3c-validator-nu.json.

2600:1f18:7d7a:2700::/56
52.22.66.203/32

Good Bot Practices scorecard

  • Identifies honestly

    Stable UA token documented (1 pattern)

  • Verifiable

    Verifiable

  • Respects robots.txt

    Does not honor robots.txt

  • Behaves

    Crawl-rate behavior is operator-declared; not machine-verifiable from this dataset

  • Reachable operator

    Operator and documentation published

Measured against the Good Bot Practices.