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Base Token Facts API – Wallet Lookup
x402
Base Token Facts API – Wallet Lookup is a paid API for AI agents from base-facts.yankii.fr, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).
Returns on-chain ETH balance, USDC balance, nonce, contract status, and current block number for a given Base mainnet wallet address.
Price / call$0.002
Success—
StatusUnknown
How this service works
Get ETH and USDC balance for a wallet address
Output
A JSON object containing the wallet's ETH balance in both wei and human-readable decimal, USDC balance in atomic units and decimal, the account nonce, a boolean indicating whether the address is a contract, the block number at which the data was fetched, and the RPC source identifier (base-mainnet-rpc).
Example use cases
DeFi bot pre-flight balance check
“Before executing a swap, check whether wallet 0xDeAdBeEf...1234 on Base has enough ETH and USDC, and tell me its current nonce.”
Fraud detection contract screening
“Is the address 0xAbCd...5678 a smart contract or a regular wallet on Base mainnet? I need to know before sending funds.”
Portfolio dashboard balance sync
“Pull the current ETH and USDC balances for 0x9999...aaaa on Base and tell me what block number those figures are from.”
Technical details
Endpoint
POSThttps://base-facts.yankii.fr/v1/wallet?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a quick, atomic snapshot of a Base mainnet wallet's ETH and USDC balances plus contract status in a single call, without running your own RPC node. Prefer it over general Ethereum RPC calls when you specifically need Base-chain data with a pay-per-call micropayment model via x402.
Side effects
- Invalid or malformed address (not 0x-prefixed or wrong length) — likely returns a 400 or error JSON
- Address not found on Base mainnet — returns zero balances and nonce 0
- RPC node unavailable or timeout — may return 5xx or connection error
- Network congestion causing stale block number data
- Payment failure via x402 protocol — 402 response if USDC payment not completed
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| address | string | 0x-prefixed address |
Output
Schema · Response
{
"type": "json",
"example": {
"eth": {
"wei": "0",
"decimal": "0.0"
},
"usdc": {
"atomic": "0",
"decimal": "0.000000"
},
"nonce": 0,
"source": "base-mainnet-rpc",
"isContract": false,
"blockNumber": "52130000"
}
}Tags
x402
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