{
  "id": "w3c-validator",
  "name": "W3C Markup Validator",
  "operator": {
    "name": "World Wide Web Consortium (W3C)",
    "url": "https://www.w3.org"
  },
  "description": "The W3C Markup Validation Service's fetcher, used when a user submits a URL to be checked for HTML conformance. W3C documents a fixed source address for its validation services alongside the user-agent string.",
  "docs": [
    "https://validator.w3.org/services"
  ],
  "category": "security",
  "user_agents": {
    "patterns": [
      "W3C_Validator/[\\d.]+"
    ],
    "instances": [
      "W3C_Validator/1.3"
    ]
  },
  "behavior": {
    "respects_robots_txt": false
  },
  "verification": [
    {
      "type": "static_cidrs",
      "cidrs": [
        "52.22.66.203/32",
        "2600:1f18:7d7a:2700::/56"
      ]
    }
  ],
  "tier": 2,
  "tier_label": "Verifiable",
  "first_seen": "2026-07-08T19:13:49.571Z",
  "resolved_cidrs": [
    "2600:1f18:7d7a:2700::/56",
    "52.22.66.203/32"
  ]
}