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Arbitrum One ERC-20 Allowance Checker
x402
Arbitrum One ERC-20 Allowance Checker is a paid API for AI agents from onchaincheck.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-29).
Returns the ERC-20 allowance a spender has on an owner's tokens on Arbitrum One, including whether it's unlimited, the owner's balance, and the actual spendable amount right now.
Price / call$0.005
Success—
StatusUnknown
How this service works
ERC-20 allowance on Arbitrum One: how much a spender may transfer from an owner, whether the approval is effectively unlimited, the owner's balance, and the amount the spender could move right now.
Output
Returns a JSON object with the raw and formatted allowance amount, the token symbol, whether the approval is effectively unlimited, the owner's current token balance, and the actual amount the spender can move right now — all scoped to Arbitrum One.
Example use cases
Audit DeFi protocol approval before swap
“Before I do this Uniswap swap on Arbitrum, check how much USDC at 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 my wallet 0xFD03AbCAdaF3F930fA4E37Eb2f6ea3A44a41b7F0 has approved for the router 0xe35e9842fceaCA96570B734083f4a58e8F7C5f2A — and tell me if it's an unlimited approval or capped.”
Verify spendable amount for automated trading bot
“My trading bot at 0xe35e9842fceaCA96570B734083f4a58e8F7C5f2A needs to move tokens from 0xFD03AbCAdaF3F930fA4E37Eb2f6ea3A44a41b7F0 — check the current allowance for ERC-20 token 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 on Arbitrum One and tell me exactly how much it can spend right now.”
Security check for suspicious wallet approval
“I think I may have approved a suspicious contract on Arbitrum — can you look up whether 0xe35e9842fceaCA96570B734083f4a58e8F7C5f2A has any allowance to spend my USDC at 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 from wallet 0xFD03AbCAdaF3F930fA4E37Eb2f6ea3A44a41b7F0, and whether it's unlimited?”
Technical details
Endpoint
GEThttps://onchaincheck.dev/arbitrum/allowance?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need real-time ERC-20 allowance data specifically on Arbitrum One, including whether the approval is unlimited and how much the spender can actually move given the owner's current balance. Prefer this over generic blockchain RPC calls when you want a clean, structured response without writing contract ABI calls. Best suited for DeFi agents auditing approvals, security monitors checking for dangerous unlimited allowances, or automated trading systems verifying they have sufficient spend authorization before executing a transaction.
Side effects
- Invalid Ethereum address format for token, owner, or spender returns a validation error
- Token address is not a valid ERC-20 contract on Arbitrum One — returns error or zero values
- No approval exists between owner and spender — returns allowance of 0
- Network or RPC issues on Arbitrum One may cause timeouts or stale data
- Missing required query parameters (token, owner, spender) returns a 400 error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"raw": "6",
"chain": "arbitrum",
"owner": "0xFD03AbCAdaF3F930fA4E37Eb2f6ea3A44a41b7F0",
"token": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
"symbol": "USDC",
"spender": "0xe35e9842fceaCA96570B734083f4a58e8F7C5f2A",
"allowance": "0.000006",
"unlimited": false,
"ownerBalance": "83629.179457",
"spendableNow": "0.000006"
}
}Tags
x402
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