{"uid":"cap_mDbpi7Ws9GZNjTZqTqHvv","slug":"erc-721-balance-checker-multi-chain-3928ada3","name":"ERC-721 Balance Checker (Multi-Chain)","description":"Use when you need how many tokens of an ERC-721 collection an address holds on Base, Ethereum, Arbitrum, Optimism or Polygon, via balanceOf, with the collection name.","url":"https://biosfera.46-62-215-147.sslip.io/o/erc721-balance?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["chain","contract","address"],"properties":{"chain":{"enum":["base","ethereum","arbitrum","optimism","polygon"],"type":"string"},"address":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$"},"contract":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$"}},"additionalProperties":false}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_G0MvjXgf_gJPrRWbj0Ir_","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the number of ERC-721 NFTs a wallet address holds in a given collection on Base, Ethereum, Arbitrum, Optimism, or Polygon.","exampleAgentPrompt":"How many NFTs does the wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 hold in the ERC-721 collection at contract 0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13d on Ethereum?","exampleUseCases":[{"title":"NFT holder eligibility check","prompt":"Can you check how many tokens the wallet 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B holds in the NFT collection at 0x60E4d786628Fea6478F785A6d7e704777c86a7c6 on Ethereum? I need to know if they qualify as a holder."},{"title":"Portfolio NFT count on Base","prompt":"How many NFTs does the address 0x1234567890abcdef1234567890abcdef12345678 hold in the collection at contract 0xabcdefabcdefabcdefabcdefabcdefabcdefabcd on Base?"},{"title":"Cross-chain NFT balance audit","prompt":"Tell me how many tokens the wallet 0xdead000000000000000042069420694206942069 owns in the ERC-721 collection deployed at 0xBd3531dA5CF5857e7CfAA92426877b022e612cf8 on Polygon."}],"resultDescription":"Returns the NFT token count (integer balance) for the specified wallet address in the given ERC-721 contract on the requested chain, along with the collection name.","failureModes":["Invalid wallet or contract address format (must be 0x + 40 hex chars)","Unsupported chain value outside of base/ethereum/arbitrum/optimism/polygon","Contract address is not a valid ERC-721 contract on the specified chain","Network congestion or RPC node unavailability causing timeout","Payment failure due to insufficient USDC balance for x402 micropayment"],"whenToPreferThis":"Use this endpoint when you need to know the raw NFT count a wallet holds in a specific ERC-721 collection across the five supported chains (Base, Ethereum, Arbitrum, Optimism, Polygon). Prefer this over general NFT portfolio APIs when you already know the contract address and just need the balanceOf result without extra metadata overhead.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T23:27:53.778Z","isFirstParty":false,"canonicalSlug":"erc-721-balance-checker-multi-chain-3928ada3"}