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Verifypost — Base Address Verification
x402
Verifypost — Base Address Verification is a paid API for AI agents from oraclepost.higgsfield.app, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-17).
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.
Price / call$0.02
Success—
StatusUnknown
How this service works
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.
Output
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.
Example use cases
Pre-payment recipient validation
“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?”
Unknown contract address classification
“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?”
Due diligence on new payee
“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.”
Technical details
Endpoint
GEThttps://oraclepost.higgsfield.app/api/premium/verifyWhen to prefer
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.
Side effects
- 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
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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