{
  "id": "w3c-css-validator",
  "name": "W3C CSS Validation Service",
  "operator": {
    "name": "World Wide Web Consortium (W3C)",
    "url": "https://www.w3.org"
  },
  "description": "W3C's CSS validator, which fetches a user-submitted page and its stylesheets to check them against the CSS specifications. It runs on W3C's Jigsaw server and identifies itself with a Jigsaw prefix followed by its own W3C_CSS_Validator_JFouffa token, from the same published validator addresses.",
  "docs": [
    "https://validator.w3.org/services"
  ],
  "category": "seo",
  "user_agents": {
    "patterns": [
      "W3C_CSS_Validator_JFouffa/[\\d.]+"
    ],
    "instances": [
      "Jigsaw/2.3.0 W3C_CSS_Validator_JFouffa/2.0"
    ]
  },
  "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": "2026-09-01T13:17:25.816Z",
  "resolved_cidrs": [
    "2600:1f18:7d7a:2700::/56",
    "52.22.66.203/32"
  ]
}