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Onchain Toolkit – Address Info (Native Balance, Nonce, Code, ERC-20)
x402
Onchain Toolkit – Address Info (Native Balance, Nonce, Code, ERC-20) is a paid API for AI agents from onchain-toolkit.bowling-anthony.workers.dev, paid per call via x402, $0.008/call, status unknown (last checked 2026-09-15).
Returns the native ETH balance, next transaction nonce, and whether an address holds contract bytecode for a given Ethereum address; optionally returns an ERC-20 token balance in the same call.
Price / call$0.008
Success—
StatusUnknown
How this service works
Native balance, next nonce, and whether an address holds contract code. Pass token to read an ERC-20 balance in the same call.
Output
Returns a JSON object containing: native balance (in wei or ETH), the next nonce (integer, safe to use for the next transaction), a boolean indicating whether the address contains contract bytecode, and optionally the ERC-20 token balance if a token contract address was supplied.
Example use cases
Pre-flight check before sending ETH
“Before I send a transaction from 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045, can you look up its current ETH balance and the next nonce I should use?”
Classify address as contract or EOA
“Is 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 a smart contract or a regular wallet? Check whether it has contract code deployed onchain.”
Check wallet ERC-20 token balance
“How many USDT tokens does the address 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B hold? Use the USDT contract at 0xdAC17F958D2ee523a2206206994597C13D831ec7.”
Technical details
Endpoint
GEThttps://onchain-toolkit.bowling-anthony.workers.dev/addressWhen to prefer
Choose this endpoint when you need a lightweight, single-call lookup of an Ethereum address's native balance, nonce, and/or contract status — especially when you also want an ERC-20 balance in the same request without needing full block explorer data. Ideal for pre-transaction checks (nonce and balance), wallet classification (EOA vs contract), and token balance queries. Prefer over full block explorer APIs when you only need these specific fields and want a low-cost, fast response.
Side effects
- Invalid or malformed Ethereum address returns a 400 error
- Unknown or unsupported network/chain results in an error response
- Invalid ERC-20 token contract address may return zero balance or an error
- Network congestion or RPC node unavailability may cause timeouts
- Payment not received (x402) results in 402 Payment Required before data is returned
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"nextNonce": 37,
"nativeBalance": "0.0142"
}
}Tags
x402
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