{"slug":"agentshelf-syntexa-ch-v1-eth-nft-owner-16ef10","title":"Call when an agent needs the ERC-721 owner of token_id on an Ethereum contract, ","host":"agentshelf.syntexa.ch","method":"POST","resource":"https://agentshelf.syntexa.ch/v1/eth-nft-owner","category":"code","description":"Call when an agent needs the ERC-721 owner of token_id on an Ethereum contract, or an ERC-1155 balanceOf(owner, id) when standard is erc1155. A missing token errors. Read-only. No spend. Send JSON {\"contract\":\"0x1111111111111111111111111111111111111111\",\"token_id\":\"1\"}. Exact $0.003 USDC on Base. Tr","price_listed":0.003,"price_asked":null,"state":"effects","state_label":"Not tested: has real-world effects","checks_7d":0,"answered_7d":0,"latency_ms_median":null,"reported_calls_30d":1,"reported_payers_30d":1,"networks":["eip155:8453"],"badge":"unverified","paid_checks_7d":0,"paid_ok_7d":0,"example_input":{"body":{"contract":"0x1111111111111111111111111111111111111111","token_id":"1"},"bodyType":"json","method":"POST","type":"http"},"output_schema":{"$schema":"https://json-schema.org/draft/2020-12/schema","properties":{"input":{"additionalProperties":false,"properties":{"body":{"additionalProperties":false,"examples":[{"contract":"0x1111111111111111111111111111111111111111","token_id":"1"}],"properties":{"contract":{"description":"NFT contract on Ethereum mainnet. Example: 0x1111111111111111111111111111111111111111. ownerOf or balanceOf is read-only.","examples":["0x1111111111111111111111111111111111111111"],"type":"string"},"owner":{"description":"Account for ERC-1155 balanceOf(owner, token_id). Example: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045. Required when standard is erc1155.","type":"string"},"standard":{"default":"erc721","description":"Token standard. erc721 (default) uses ownerOf or tokenURI. erc1155 uses balanceOf(owner, id) or uri(id) with {id} substitution.","enum":["erc721","erc1155"],"type":"string"},"token_id":{"description":"Token id as a decimal integer. Example: 1. A JSON number is accepted when it is a safe integer. A missing ERC-721 token errors.","examples":["1"],"pattern":"^(0|[1-9]\\d*)$","type":"string"}},"required":["contract","token_id"],"type":"object"},"bodyType":{"enum":["json","form-data","text"],"type":"string"},"method":{"enum":["POST"],"type":"string"},"type":{"const":"http","type":"string"}},"required":["type","method","bodyType","body"],"type":"object"},"output":{"properties":{"example":{"additionalProperties":false,"examples":[{"balance":null,"billed":true,"contract":"0x1111111111111111111111111111111111111111","network":"eip155:1","ok":true,"owner":"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045","receipt_id":"rcpt_01EXAMPLE000000000000000","standard":"erc721","supports_erc1155":null,"supports_erc721":true,"token_id":"1","warnings":[]}],"properties":{"balance":{"examples":[null],"type":["string","null"]},"billed":{"examples":[true],"type":"boolean"},"contract":{"examples":["0x1111111111111111111111111111111111111111"],"type":"string"},"network":{"const":"eip155:1","examples":["eip155:1"],"type":"string"},"ok":{"const":true,"examples":[true],"type":"boolean"},"owner":{"examples":["0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"],"type":"string"},"receipt_id":{"examples":["rcpt_01EXAMPLE000000000000000"],"type":"string"},"standard":{"enum":["erc721","erc1155"],"examples":["erc721"],"type":"string"},"supports_erc1155":{"examples":[null],"type":["boolean","null"]},"supports_erc721":{"examples":[true],"type":["boolean","null"]},"token_id":{"examples":["1"],"type":"string"},"warnings":{"default":[],"examples":[[]],"items":{"type":"string"},"type":"array"}},"required":["ok","receipt_id","billed","network","contract","token_id","standard","owner","balance","supports_erc721","supports_erc1155"],"type":"object"},"type":{"type":"string"}},"required":["type"],"type":"object"}},"required":["input"],"type":"object"},"history":[],"description_full":"Call when an agent needs the ERC-721 owner of token_id on an Ethereum contract, or an ERC-1155 balanceOf(owner, id) when standard is erc1155. A missing token errors. Read-only. No spend. Send JSON {\"contract\":\"0x1111111111111111111111111111111111111111\",\"token_id\":\"1\"}. Exact $0.003 USDC on Base. Try unpaid POST /v1/sandbox/eth-nft-owner first.","last_updated":"2026-10-20T07:39:11.195Z","schemes":["exact"]}