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ERC721 Token Owner Lookup
x402
ERC721 Token Owner Lookup is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-01).
Returns the current owner address of a specific ERC721 NFT token on any of ten supported EVM chains
Price / call$0.003
Success—
StatusUnknown
How this service works
Who currently owns one ERC721 token — Genesis402 / UnyKorn Operator Network
Output
Returns a JSON object with ok:true, the type field set to 'erc721-owner', the current owner wallet address, and a receipt object containing the transaction hash, USD cost, and a unique receipt ID for the call.
Example use cases
NFT ownership verification for access control
“Can you check who owns token ID 512 of the contract 0xBd3531dA5CF5857e7CfAA92426877b022e612cf8 on Ethereum? I need to verify if a specific wallet actually holds it before granting access.”
Marketplace provenance check on Base
“Look up the current owner of token ID 101 on the NFT contract 0x2b4a66557A79263275826AD31a4cDDc2789334bD on Base — I want to confirm who I'd be buying from before making an offer.”
Cross-chain NFT portfolio audit
“Who owns token ID 3 of the contract 0xd9145CCE52D386f254917e481eB44e9943F39138 on Polygon? I'm building a report of where certain NFTs ended up across different chains.”
Technical details
Endpoint
POSThttps://twin.unykorn.org/erc721-owner?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a fast, pay-per-call lookup of the current owner of a single ERC721 token across any of ten major EVM chains (Ethereum, Base, Polygon, Arbitrum, Optimism, BSC, Avalanche, Gnosis, Linea, Scroll) without setting up your own RPC infrastructure. It is ideal for agents that need on-demand NFT ownership verification with built-in payment receipts.
Side effects
- Invalid contract address format (must be 0x-prefixed 40 hex chars) returns validation error
- Unsupported chain name returns enum validation error
- Token ID that does not exist on the contract may return a zero address or error
- Network RPC issues on the target chain may cause a timeout or upstream error
- Insufficient x402 payment results in 402 Payment Required response
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| params | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"type": "erc721-owner",
"receipt": {
"tx_hash": "0x<64hex>",
"amount_usd": 0.003,
"receipt_id": "g402-<16hex>"
},
"generated_at": "<iso8601>"
}
}Tags
x402
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