{"uid":"cap_2f5QfG0yx5-ygQry5GTX_","slug":"eth-mainnet-erc-721-owner-lookup-37a10e57","name":"ETH Mainnet 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://ari001.tailb4ac3a.ts.net/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":"base","method":"ownerOf","result":{"id":"5256424","owner":"0x456979e89917f4dc1e86662fcdfd4c9766c6684d","token":"0xa990c6a764b73bf43cee5bb40339c3322fb9d55f"},"service":"x402_chain_reads_v1.base_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":"down","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_Isy64V3YITEP_ohJvzq_C","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 owner address of a specific ERC-721 NFT token on Ethereum mainnet given its contract address and token ID.","exampleAgentPrompt":"Who currently owns token ID 5765 on the Bored Ape Yacht Club contract at 0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13d on Ethereum mainnet?","exampleUseCases":[{"title":"Verify NFT ownership before gating access","prompt":"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?"},{"title":"Track current holder of a high-value NFT","prompt":"I want to know who currently holds CryptoPunk #7804 — the contract is 0xb47e3cd837dDF8e4c57F05d70Ab865de6e193BBB and the token ID is 7804."},{"title":"Audit NFT provenance for a marketplace listing","prompt":"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."}],"resultDescription":"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.","failureModes":["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"],"whenToPreferThis":"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.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-31T01:28:47.830Z","isFirstParty":false,"canonicalSlug":"eth-mainnet-erc-721-owner-lookup-37a10e57"}