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ERC-20 Token Balance Lookup on Base (x402)
x402
ERC-20 Token Balance Lookup on Base (x402) is a paid API for AI agents from kr-x402-mvp.kgy5612.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-31).
Returns the ERC-20 token balance of a wallet address on the Base chain, including symbol, decimals, raw and human-readable balance, and current block number.
Price / call$0.003
Success—
StatusUnknown
How this service works
Pay-per-call crypto microdata for trading/onchain AI agents via x402 (USDC on Base): Base gas, token risk, balances, multi-venue prices, Hyperliquid book/funding, kimchi premium. No API keys.
Output
A JSON object containing the block number at which the balance was read, chain name ('base'), token contract address, token symbol, wallet address, human-readable balance (float), number of decimals, and the raw integer balance string (e.g. '61000' for 0.061 USDC).
Example use cases
Pre-payment balance verification
“Before I send USDC to 0xabc123...def456, check whether that wallet already holds any USDC on Base — the USDC contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.”
Agent self-check before gas-heavy trade
“Check my own wallet 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 to confirm I have enough USDC on Base to cover the next few micro-payments — token contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.”
Counterparty due-diligence for DeFi agent
“I'm about to enter a trade with counterparty wallet 0xdead...beef — can you look up how much of token 0x4200000000000000000000000000000000000006 they're holding on Base right now?”
Technical details
Endpoint
GEThttps://kr-x402-mvp.kgy5612.workers.dev/api/erc20-balance?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a real-time ERC-20 token balance for any wallet on the Base chain without setting up API keys — ideal for AI agents that pay per call in USDC via the x402 protocol. Prefer it over full node RPC calls when you want a simple REST interface with no infrastructure setup, and over free public RPCs when reliability and structured JSON output matter.
Side effects
- Invalid token or wallet address format (must be 0x-prefixed 40-hex-char address) returns a 4xx error
- Token contract does not exist on Base returns zero balance or RPC error
- Payment not included or insufficient USDC payment via x402 returns HTTP 402
- RPC node congestion or Base chain downtime may cause timeouts
- Querying an EOA address as a token contract returns nonsensical results
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"block": 53204016,
"chain": "base",
"token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"symbol": "USDC",
"wallet": "0xe4be4d0bd82d8e68203deff81f79ede0529f2617",
"balance": 0.061,
"decimals": 6,
"balance_raw": "61000"
}
}Tags
x402
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