Domain Availability Checker

Give this API up to 10 domain names and it will tell you whether each one has a registration record on file with the official registry. It uses RDAP — the modern, structured replacement for WHOIS — so there is no messy free-text parsing. Each domain comes back labeled 'registered', 'unregistered', or 'indeterminate' (when the registry does not support RDAP for that ending). Important: 'unregistered' means no record was found, which usually means the name is available — but reserved or premium names can also return no record. This API tells you registration status only; it does not tell you price, premium status, or whether a registrar will actually let you buy the name.

Resource: domain-availability-checker.underscoredone.com/check

Network: eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp · Asset: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 · Pay to: 0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08

Payment methods: — · Last validation: —

{
  "input": {
    "body": {
      "domains": [
        "example.com",
        "mybrand.ai",
        "coolstartup.io"
      ]
    },
    "type": "http",
    "method": "POST",
    "bodyType": "json"
  },
  "output": {
    "type": "json",
    "example": {
      "count": 2,
      "results": [
        {
          "note": "A registration record exists for this domain.",
          "domain": "example.com",
          "status": "registered",
          "registered": true,
          "rdap_source": "registry",
          "tld_supported": true
        },
        {
          "note": "No registration record found. Usually means unregistered, but reserved or premium names can also return this result.",
          "domain": "thisnameprobablyhasnorecord12345.ai",
          "status": "unregistered",
          "registered": false,
          "rdap_source": "registry",
          "tld_supported": true
        }
      ],
      "disclaimer": "Status reflects whether a registration record exists. It does not confirm price, premium status, or that an 'unregistered' name is purchasable at standard cost.",
      "queried_at": "2026-06-26T09:00:00Z",
      "api_version": "1.0.0"
    }
  },
  "paymentRequirements": [
    {
      "raw": {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "payTo": "0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08",
        "amount": "10000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 300
      },
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "payTo": "0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08",
      "scheme": "exact",
      "network": "eip155:8453",
      "amountAtomic": "10000"
    },
    {
      "raw": {
        "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
        "extra": {
          "feePayer": "BENrLoUbndxoNMUS5JXApGMtNykLjFXXixMtpDwDR9SP"
        },
        "payTo": "8ugAWAXDB8V18kiUrGZTq1oMvU3C6Fxs8hfC6rvzQT3b",
        "amount": "10000",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 300
      },
      "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
      "payTo": "8ugAWAXDB8V18kiUrGZTq1oMvU3C6Fxs8hfC6rvzQT3b",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "amountAtomic": "10000"
    }
  ]
}

Source catalog records are retained separately from live endpoint observations. Sonar score, uptime, and latency are advisory metrics. CDP indexing is not inferred from validation.