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SiteCheck EVM ERC-20 Token Allowance Checker
x402
SiteCheck EVM ERC-20 Token Allowance Checker is a paid API for AI agents from api.sitecheck-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-30).
Returns the ERC-20 token spending allowance granted by a token owner to a spender address on a specified EVM chain
Price / call$0.002
Success—
StatusUnknown
How this service works
ERC-20 allowance an owner has granted a spender for one token: raw and human amount, with the token's symbol and decimals. unlimited is true when the allowance is at least 2^255, the usual approve-everything value. Read-only.
Output
Returns a JSON object containing the raw uint256 allowance string, a human-readable decimal amount, a boolean 'unlimited' flag, the token symbol and decimals, the chain name, the owner and spender addresses, and a timestamp of when the check was performed. Also includes the RPC source used for the on-chain call.
Example use cases
DeFi approval audit before swap
“Before I do a swap on Uniswap on Base, check how much USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) my wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 has approved the Uniswap router 0x2626664c2603336E57B271c5C0b26F421741e481 to spend.”
Wallet security allowance review
“Has my Ethereum wallet 0xabc123…def456 given unlimited spending approval to any spender for the USDT token at 0xdAC17F958D2ee523a2206206994597C13D831ec7? Check with spender 0xE592427A0AEce92De3Edee1F18E0157C05861564.”
Smart contract integration pre-check
“I'm building a DeFi integration on Arbitrum — can you check if owner 0x1111111111111111111111111111111111111111 has already approved spender 0x2222222222222222222222222222222222222222 for WETH token 0x82aF49447D8a07e3bd95BD0d56f35241523fBab1, and if so how much?”
Technical details
Endpoint
GEThttps://api.sitecheck-api.workers.dev/api/evm/allowance?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to check ERC-20 token spending permissions on EVM-compatible chains (Base, Ethereum, Arbitrum, Optimism, Polygon) without running your own node. Ideal for DeFi agents auditing approvals before swaps, security tools scanning for unlimited approvals, and integration checks verifying that a contract has been pre-approved by a user.
Side effects
- Invalid or malformed 0x address for owner, token, or spender returns an error
- Unsupported chain name causes a validation error
- Token contract does not implement ERC-20 allowance function (non-standard contract) may return zero or error
- RPC node unavailability on the target chain causes a timeout or upstream error
- Network congestion may cause slow response for certain chains
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"raw": "115792089237316195423570985008687907853269984665640564039457584007913082113074",
"chain": "base",
"owner": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
"token": {
"symbol": "USDC",
"address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"decimals": 6
},
"amount": 1.157920892373162e+71,
"source": "https://base-rpc.publicnode.com (eth_call allowance, decimals, symbol)",
"spender": "0x2626664c2603336E57B271c5C0b26F421741e481",
"checkedAt": "2026-10-14T04:49:19.405Z",
"unlimited": true,
"disclaimer": "Information only, not financial advice."
}
}Tags
x402
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