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Arbitrum ERC-20 Allowance Checker
Arbitrum ERC-20 Allowance Checker is a paid API for AI agents from agent-data-tools.revmesh2074.workers.dev, paid per call via x402, $0.01/call, status unknown.
Returns the ERC-20 token allowance (raw and human-readable) that a spender is approved to move from an owner's wallet on Arbitrum One, plus whether the approval is unlimited.
Price / call$0.01
Success—
StatusUnknown
How this service works
ERC-20 token allowance on Arbitrum One: how much a spender may move from an owner's wallet (allowance), raw and in token units, and whether the approval is unlimited. Use to check an approval before a swap or to audit risky open approvals; for the owner's balance use arb_token_balance. Token is a ticker (USDC, USDT, WETH…) or a 0x contract; a missing contract is 404 and a non-ERC-20 422, both uncharged.
Output
Returns a JSON object with: the human-readable allowance amount (string, in token units), the raw allowance in base units, a boolean 'unlimited' flag indicating a max-uint256 approval, the token symbol, decimals, chain name, chain ID, and the owner and spender addresses. A 404 means the token contract was not found; a 422 means the contract exists but is not ERC-20 compliant; both are uncharged.
Example use cases
Pre-swap approval check on Arbitrum
“Before I execute this WETH swap on Arbitrum, can you check whether the Uniswap router (0x4C60051384bd2d3C01bfc845Cf5F4b44bcbE9de5) has enough WETH allowance from my wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 to cover a 2 WETH trade?”
Audit risky unlimited token approvals
“I want to audit my Arbitrum wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 — can you check whether I've given unlimited USDC approval to the Aave v3 pool contract 0x794a61358D6845594F94dc1DB02A252b5b4814aD?”
Security review of spender allowances
“Can you check if the spender contract 0x1111111254EEB25477B68fb85Ed929f73A960582 has any USDT allowance on my Arbitrum wallet 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B, and whether the approval is unlimited?”
Technical details
Endpoint
GEThttps://agent-data-tools.revmesh2074.workers.dev/arb/allowance?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to check the ERC-20 spend approval for a specific owner-spender pair on Arbitrum One before a swap, DeFi interaction, or security audit. It supports both ticker symbols (USDC, WETH) and raw contract addresses, and explicitly flags unlimited approvals — making it ideal for both pre-transaction validation and security auditing. Use arb_token_balance instead if you need the owner's actual token balance rather than an approval amount. For allowance checks on other chains (Polygon, Optimism, Base, Ethereum), use the equivalent chain-specific endpoint.
Side effects
- 404 - token ticker or contract address not found on Arbitrum (not charged)
- 422 - contract address exists but does not implement ERC-20 interface (not charged)
- Invalid owner or spender address format causing a bad request
- RPC timeout or Arbitrum node unavailability causing a transient error
- Querying a token with non-standard decimals may cause unexpected allowance formatting
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| ownerrequired | string | 0x wallet that gave the approval |
| tokenrequired | string | Token: a ticker such as USDC or WETH, or the 0x ERC-20 contract address |
| spenderrequired | string | 0x contract or wallet allowed to spend (the example is Uniswap Permit2) |
Output
Schema · Response
| Field | Type | Description |
|---|---|---|
| raw | string | |
| chain | string | |
| owner | string | |
| token | string | |
| symbol | string | |
| chainId | number | |
| spender | string | |
| decimals | number | |
| allowance | string | |
| unlimited | boolean |
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