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Ethereum ERC-20 Balance (balanceOf)
x402
Ethereum ERC-20 Balance (balanceOf) is a paid API for AI agents from api.arysphere.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-17).
Returns the raw ERC-20 token balance of a holder address on Ethereum mainnet by calling the contract's balanceOf function.
Price / call$0.002
Success—
StatusUnknown
How this service works
ARYSPHERE sells AI-written verdicts on Base token contracts (a grade, a one-liner, a roast and the contract's facts) and Base/Ethereum chain reads, paid per call in USDC on Base over x402 v2. No account and no API key.
Output
A JSON object with fields: ok (boolean success flag), chain (always 'base' or 'ethereum' identifier), method ('balanceOf'), result (the raw integer token balance as a string, in the token's smallest unit), and service (the internal service identifier). The raw balance must be divided by 10^decimals to get a human-readable amount.
Example use cases
DeFi portfolio balance snapshot
“Check how many tokens wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 holds of the USDT contract 0xdAC17F958D2ee523a2206206994597C13D831ec7 on Ethereum mainnet right now.”
Eligibility check for token-gated access
“Does the address 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B hold any tokens of the NFT-adjacent ERC-20 contract 0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984 on Ethereum — return the raw balance so I can check if it's above zero.”
Pre-transfer balance verification
“Before I send a transaction, can you read the on-chain balanceOf for wallet 0x742d35Cc6634C0532925a3b844Bc454e4438f44e against the DAI contract 0x6B175474E89094C44Da98b954EedeAC495271d0F on Ethereum mainnet?”
Technical details
Endpoint
GEThttps://api.arysphere.com/v1/ventures/x402_eth_reads_v1/eth_mainnet_erc20_balanceof?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need the live on-chain ERC-20 balanceOf value for any token/holder pair on Ethereum mainnet without running your own node. It is ideal for lightweight, single-address balance queries paid per-call via x402 micropayments. Prefer this over bundle endpoints when you need only the ERC-20 balance and want to minimize cost. Choose the ERC-20 Allowance sibling endpoint instead if you need to check how much a spender is permitted to spend on behalf of the holder.
Side effects
- Invalid contract address format (not 0x + 40 hex) returns a 400 error
- Invalid holder address format returns a 400 error
- Contract address is not a valid ERC-20 contract — call may revert or return 0
- Payment not provided or insufficient — x402 payment required at $0.002 USDC
- Ethereum mainnet RPC unavailable — service may return 5xx error
- Address with zero balance returns result: '0' (not an error, but agents must handle this correctly
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"chain": "ethereum",
"method": "balanceOf",
"result": "291368219",
"service": "x402_eth_reads_v1.eth_mainnet_erc20_balanceof"
}
}Tags
x402
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