{"uid":"cap_lLhyaBxoaoeKCEnfH9Rml","slug":"verifypost-base-address-verification-90b80de8","name":"Verifypost — 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/premium/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":"0.02","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":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_c-PwGtYCWyR5IKZgNLB9d","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Checks whether a Base blockchain address is a contract or EOA wallet, and returns its activity status (code size, nonce, ETH balance, USDC balance) at the latest block.","exampleAgentPrompt":"Before I send payment, can you verify whether 0x1234567890abcdef1234567890abcdef12345678 is a contract or a regular wallet on Base, and tell me if it's active — show me its ETH and USDC balance and transaction count?","exampleUseCases":[{"title":"Pre-payment recipient validation","prompt":"I'm about to pay 0xAbCdEf1234567890AbCdEf1234567890AbCdEf12 on Base — can you check if that address is a real active wallet or a contract, and what its ETH and USDC balances are, before I send anything?"},{"title":"Unknown contract address classification","prompt":"Someone gave me this Base address 0xDEADbeef00000000000000000000000000000001 and claimed it's a smart contract — can you verify if it's actually a contract and whether it's ever been used?"},{"title":"Due diligence on new payee","prompt":"We're onboarding a new vendor whose Base payout address is 0x9999999999999999999999999999999999999999 — please check if it's a contract or EOA, confirm it has some transaction history, and tell me its current balances."}],"resultDescription":"Returns the account type (contract if code size > 0, EOA otherwise), the raw code size in bytes, the nonce (total transaction count), the current ETH balance, and the current USDC balance — all read live from the Base chain at the latest block with no caching.","failureModes":["Invalid or malformed address (not 0x-prefixed or wrong length) returns an error","Address with zero nonce and zero balances may appear inactive even if valid","RPC node unavailability could cause transient read failures","Non-Base EVM addresses (e.g. Ethereum mainnet) may return misleading results if the address exists on both chains"],"whenToPreferThis":"Choose this endpoint when you need to perform pre-payment due diligence on an unknown Base address — it uniquely combines contract-vs-EOA classification, activity check (nonce), and balance snapshot in a single live read with no third-party APIs or caching. Prefer it over wallet-only balance endpoints when you also need to know whether the recipient is a smart contract.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-19T12:49:19.561Z","isFirstParty":false}