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Onchain Balance Lookup (Base & Ethereum)
x402
Onchain Balance Lookup (Base & Ethereum) is a paid API for AI agents from onchain.x402utils.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-30).
Returns live ETH and USDC balances for a given wallet address on Base or Ethereum, along with the current block number.
Price / call$0.001
Success—
StatusUnknown
How this service works
Live Base and Ethereum reads for AI agents: balances (ETH + USDC), gas, transaction status, ERC-20 metadata. $0.001 per call via x402 (USDC on Base).
Output
A JSON object containing the ETH balance, USDC balance, current block number, chain name, and the queried address — all reflecting the live on-chain state at the time of the call.
Example use cases
Pre-payment wallet solvency check
“Before we send that payment, check whether wallet 0xdB6381Df2D754965804547940Bc852D9a1bc612f has at least 10 USDC available on Base.”
Agent treasury monitoring
“What are the current ETH and USDC balances for our agent's treasury wallet 0xABCDEF1234567890abcdef1234567890ABCDEF12 on Ethereum?”
User portfolio snapshot
“Give me a quick snapshot of ETH and USDC holdings for address 0x742d35Cc6634C0532925a3b844Bc454e4438f44e on Base right now.”
Technical details
Endpoint
GEThttps://onchain.x402utils.workers.dev/v1/balance?utm_source=zero.xyzWhen to prefer
Use this endpoint when an AI agent needs a lightweight, pay-per-call read of live ETH or USDC balances on Base or Ethereum without setting up a full RPC node or indexer. Ideal for micro-transaction workflows, balance checks before payments, or treasury monitoring where cost predictability ($0.001/call) matters.
Side effects
- Invalid or malformed address (missing 0x prefix or wrong length) returns an error
- Unsupported chain value other than 'base' or 'ethereum' may return an error or default to base
- Missing required 'address' query parameter results in a validation error
- Payment failure via x402 protocol if USDC on Base is insufficient
- Network timeouts or RPC node unavailability causing delayed or failed reads
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"eth": "0.0",
"usdc": "0.0",
"block": 39000000,
"chain": "base",
"address": "0xdB6381Df2D754965804547940Bc852D9a1bc612f"
}
}Tags
x402
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