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OneSource ERC20 Token Balance
x402
OneSource ERC20 Token Balance is a paid API for AI agents from api.onesource.io, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-13).
Returns the ERC20 token balance for any Ethereum wallet address by calling balanceOf on-chain via live Ethereum RPC
Price / call$0.003
Success—
StatusUnknown
How this service works
ERC20 token balance for any Ethereum wallet - USDC, USDT, DAI, or any token - via balanceOf (eth_call) on OneSource live Ethereum RPC
Output
Returns the raw on-chain ERC20 token balance for the specified wallet address, retrieved via a live eth_call (balanceOf) against the OneSource Ethereum RPC. The balance is typically in the token's smallest unit (e.g. wei or 6-decimal units for USDC/USDT).
Example use cases
Verify user has sufficient stablecoin
“Can you check if the wallet 0x742d35Cc6634C0532925a3b844Bc927e4F5e9cE3 holds at least 5000 USDC on Ethereum mainnet before we process their payment?”
Monitor DeFi protocol token holdings
“What's the current balance of UNI tokens (0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984) for the Uniswap governance vault at 0x1a9c8182c09db50e33aa9b7075033bd9dfb5a5a9?”
Cross-chain bridge readiness check
“How many USDT tokens (0xdac17f958d2ee523a2206206994597c13d831ec7) does this Sepolia testnet wallet 0x8ba1f109551bD432803012645Ac136ddd64DBA72 have before initiating the bridge?”
Technical details
Endpoint
GEThttps://api.onesource.io/api/chain/erc20-balanceWhen to prefer
Use this endpoint when you need to check the on-chain ERC20 token balance for a specific wallet address on Ethereum mainnet or Sepolia testnet. Prefer this over the combined live wallet endpoint when you only need a single token's balance and want a lightweight, targeted eth_call rather than a multi-asset query.
Side effects
- Invalid token address format (not a valid 0x hex address) — returns 400 or validation error
- Invalid account address format — returns 400 or validation error
- Token contract does not implement ERC20 balanceOf — may return zero or an RPC error
- Network value not in enum (ethereum, sepolia) — returns validation error
- RPC node temporarily unavailable — returns 5xx error
- Wallet has no balance — returns 0 (not an error)
Input
{
"token": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
"account": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
"network": "ethereum"
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
{
"data": {
"name": "USD Coin",
"symbol": "USDC",
"account": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
"balance": "31127137",
"decimals": 6,
"contract_address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"
},
"meta": {
"endpoint": "/api/chain/erc20-balance",
"request_id": "be23b9a9ff0bda0a"
}
}Schema · Response
{
"type": "json",
"example": {
"data": {
"name": "Tether USD",
"symbol": "USDT",
"account": "0xd8da6bf26964af9d7eed9e03e53415d37aa96045",
"balance": "1234567890",
"decimals": 6,
"contract_address": "0xdac17f958d2ee523a2206206994597c13d831ec7"
},
"meta": {
"endpoint": "/api/chain/erc20-balance",
"cost_usdc": "0.001",
"request_id": "00000000abcdef01",
"payment_chain": "base",
"payment_token": "USDC"
}
}
}Tags
x402
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