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ETH Mainnet ERC-721 Owner Lookup
x402
ETH Mainnet ERC-721 Owner Lookup is a paid API for AI agents from ari001.tailb4ac3a.ts.net, paid per call via x402, $0.003/call, status down (last checked 2026-10-31).
Returns the owner address of a specific ERC-721 NFT token on Ethereum mainnet given its contract address and token ID.
Price / call$0.003
Success—
StatusDown
How this service works
ARYSPHERE sells AI-written verdicts on Base token contracts (a grade, a one-liner, a roast and the contract's facts) and Base/Ethereum chain reads, paid per call in USDC on Base over x402 v2. No account and no API key.
Output
Returns the Ethereum wallet address (0x + 40 hex characters) of the current owner of the specified ERC-721 token, as returned by the contract's ownerOf function on Ethereum mainnet.
Example use cases
Verify NFT ownership before gating access
“Before granting this user access to our NFT-holders-only Discord channel, can you check whether wallet 0xAbc... actually owns token ID 42 on the contract 0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13d?”
Track current holder of a high-value NFT
“I want to know who currently holds CryptoPunk #7804 — the contract is 0xb47e3cd837dDF8e4c57F05d70Ab865de6e193BBB and the token ID is 7804.”
Audit NFT provenance for a marketplace listing
“Before we list this NFT for sale, can you confirm the current on-chain owner of token ID 999 on contract 0xAbCd1234...? I need to make sure the seller actually owns it.”
Technical details
Endpoint
GEThttps://ari001.tailb4ac3a.ts.net/v1/ventures/x402_eth_reads_v1/eth_mainnet_erc721_ownerof?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to resolve the current on-chain owner of a specific ERC-721 NFT on Ethereum mainnet. Prefer it over general blockchain explorers when you need a programmatic, structured response for an agent workflow. It is purpose-built for the ownerOf ERC-721 call, making it more reliable than a generic RPC endpoint for this specific operation.
Side effects
- Token ID does not exist or has been burned — contract may revert with an error
- Invalid contract address format (not 0x + 40 hex) — request rejected by schema validation
- Contract address is not a valid ERC-721 contract — may return unexpected results or error
- Network congestion or RPC unavailability — timeout or 5xx error
- Incorrect token ID format (non-decimal) — query parameter parsing failure
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"chain": "base",
"method": "ownerOf",
"result": {
"id": "5256424",
"owner": "0x456979e89917f4dc1e86662fcdfd4c9766c6684d",
"token": "0xa990c6a764b73bf43cee5bb40339c3322fb9d55f"
},
"service": "x402_chain_reads_v1.base_erc721_ownerof"
}
}Tags
x402
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