{"uid":"cap_WiT6LyzraNRuAANeriy3T","slug":"addresscheck-base-address-verification-9f49b56a","name":"Addresscheck — Base Address Verification","description":"Is this Base address a contract or a wallet, and is it active? Live read: code size (contract vs EOA), transaction count (nonce), ETH and USDC balance, at the latest block. Pass ?address=0x... . Useful before paying an unknown payTo. No third-party API, no cache.","url":"https://oraclepost.higgsfield.app/api/verify","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":{"const":"http"},"method":{"const":"GET"},"queryParams":{"type":"object","required":["address"],"properties":{"address":{"type":"string","description":"EVM address on Base, 0x-prefixed"}}}}},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{}}}}},"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":"unknown","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_tNVviH-keLMtM054nbseu","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":"Checks whether an Ethereum Base network address is a contract or EOA wallet, and returns its activity status including ETH/USDC balance and transaction count at the latest block.","exampleAgentPrompt":"Before I send payment to 0x742d35Cc6634C0532925a3b844Bc454e4438f44e, can you verify whether that Base address is a contract or a regular wallet, and tell me if it's active — including its ETH and USDC balance?","exampleUseCases":[{"title":"Pre-payment recipient validation","prompt":"I'm about to send USDC to 0x4e68Ccd3E89f51C3074ca5072bbAC773960dFa36 on Base — can you check if that address is a real wallet or a contract, and whether it's ever had any transactions?"},{"title":"Smart contract deployment check","prompt":"Can you tell me if 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Base is a deployed smart contract or just a regular EOA wallet?"},{"title":"Unknown counterparty due diligence","prompt":"Someone just sent me a payment address 0x1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b and I want to know if it's legitimate — is it a contract or a wallet, how much ETH and USDC does it hold, and does it have any transaction history on Base?"}],"resultDescription":"Returns whether the address is a smart contract or EOA (based on code size), its nonce/transaction count, current ETH balance, current USDC balance, and the block number at which data was read — all fetched live from the Base chain with no caching.","failureModes":["Invalid or missing address parameter returns an error","Non-0x-prefixed address fails validation","Addresses not on Base network may return zero values or errors","Network RPC node unavailability causes request failure","Checksum-invalid addresses may be rejected"],"whenToPreferThis":"Use this endpoint when you need real-time, uncached verification of a Base network address before executing a payment or interaction — specifically when you want to distinguish contracts from wallets AND check activity/balance in a single call. Prefer over generic balance checkers when recipient type (contract vs EOA) matters for safety or routing logic.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-19T12:50:51.437Z","isFirstParty":false}