{"uid":"cap_f_Rt6QNQmqiHy67cNN9Q0","slug":"ethereum-erc-721-owner-lookup-1e9c3181","name":"Ethereum ERC-721 Owner Lookup","description":"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.","url":"https://api.arysphere.com/v1/ventures/x402_eth_reads_v1/eth_mainnet_erc721_ownerof?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"queryParams":{"type":"object","properties":{"id":{"type":"string","description":"token id, decimal"},"token":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","description":"ERC-721 contract, 0x + 40 hex"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"ok":true,"chain":"ethereum","method":"ownerOf","result":{"id":"1","owner":"0x46efbaedc92067e6d60e84ed6395099723252496","token":"0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D"},"service":"x402_eth_reads_v1.eth_mainnet_erc721_ownerof"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.003","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.003/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_WTHQMYzi6o8pkhCnn6Zvb","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.003","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the current owner address of a specific ERC-721 NFT token on Ethereum mainnet given a contract address and token ID.","exampleAgentPrompt":"Who currently owns token ID 5256 of the ERC-721 contract at 0xa990c6a764b73bf43cee5bb40339c3322fb9d55f on Ethereum mainnet?","exampleUseCases":[{"title":"Verify NFT ownership before transfer","prompt":"Before I send payment to this seller, can you confirm that wallet 0x456979e89917f4dc1e86662fcdfd4c9766c6684d actually owns token ID 1001 of the NFT contract 0xa990c6a764b73bf43cee5bb40339c3322fb9d55f on Ethereum mainnet?"},{"title":"Audit NFT holder for allowlist","prompt":"I need to check who currently holds token ID 78 of the ERC-721 contract 0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d on Ethereum mainnet — we're building an allowlist and need the current owner's address."},{"title":"Monitor NFT ownership change","prompt":"Can you look up the current owner of token ID 9999 for the ERC-721 contract 0x34d85c9cdeb23fa97cb08333b511ac86e1c4e258 on Ethereum mainnet so I can compare it against who owned it last week?"}],"resultDescription":"Returns a JSON object with ok status, the chain identifier ('ethereum' or 'base'), the method name ('ownerOf'), and a result object containing the token contract address, the decimal token ID, and the current owner's Ethereum wallet address (0x format).","failureModes":["Invalid contract address format (not 0x + 40 hex) returns a validation error","Token ID does not exist on the contract returns a revert/not-found error","Contract address is not an ERC-721 contract returns a call failure","Network congestion or RPC timeout may cause delayed or failed responses","Payment of 0.003 USDC not provided or rejected results in 402 Payment Required"],"whenToPreferThis":"Choose this endpoint when you specifically need to resolve the current owner of an ERC-721 NFT on Ethereum mainnet by contract address and token ID. Prefer it over generic blockchain explorers when you need a programmatic, pay-per-call response with a clean JSON structure suitable for agent pipelines. It is distinct from Base network equivalents when Ethereum mainnet ownership data is required.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-17T12:40:56.136Z","isFirstParty":false,"canonicalSlug":"ethereum-erc-721-owner-lookup-1e9c3181"}