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Polygon PoS ERC-20 Allowance Checker
x402
Polygon PoS 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 Polygon PoS, whether it is unlimited, the owner's current balance, and the net spendable amount right now.
Price / call$0.005
Success—
StatusUnknown
How this service works
ERC-20 allowance on Polygon PoS: 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
A JSON object containing the raw and human-readable allowance, whether it is effectively unlimited (boolean), the owner's current ERC-20 balance, the net amount the spender can move right now (minimum of allowance and balance), the token symbol, and the chain identifier.
Example use cases
DeFi approval security audit
“Check the USDC allowance on Polygon PoS for the Uniswap router at 0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45 from my wallet 0x357542d88744DB4BFfE8F90008138dDc4a10cdC3 — is it set to unlimited, and what's my actual balance?”
Smart contract spending limit check
“Before I submit this transaction, can you look up how much of my USDT token at 0xc2132D05D31c914a87C6611C10748AEb04B58e8F the lending protocol at 0x8dFf5E27EA6b7AC08EbFdf9eB090F32ee9a30fcf is approved to spend from my Polygon address 0xAbCd1234567890AbCd1234567890AbCd12345678?”
Monitoring approval after revoke
“I just revoked an approval on Polygon — can you confirm that the allowance for spender 0x429eba38eF16A42C62b497C22A4662C45b37f848 on the USDC contract 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359 from owner 0x357542d88744DB4BFfE8F90008138dDc4a10cdC3 is now zero?”
Technical details
Endpoint
GEThttps://onchaincheck.dev/polygon/allowance?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to check ERC-20 token approvals specifically on Polygon PoS, including whether an approval is effectively unlimited (max uint256). Prefer this over generic block explorers when you need a structured, machine-readable response combining allowance, balance, and spendable amount in one call. Ideal for DeFi security checks, approval audits, and pre-transaction validation on Polygon.
Side effects
- Invalid Ethereum address format returns a validation error
- Token contract address is not a valid ERC-20 on Polygon PoS — returns error or zero values
- Owner or spender address does not exist onchain — returns zero allowance and balance
- Network connectivity issues to Polygon PoS RPC — may return 5xx error
- Payment not included or invalid — returns 402 Payment Required
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"raw": "115792089237316195423570985008687907853269984665640564039457584007913129639935",
"chain": "polygon",
"owner": "0x357542d88744DB4BFfE8F90008138dDc4a10cdC3",
"token": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
"symbol": "USDC",
"spender": "0x429eba38eF16A42C62b497C22A4662C45b37f848",
"allowance": "115792089237316195423570985008687907853269984665640564039457584007913129.639935",
"unlimited": true,
"ownerBalance": "0",
"spendableNow": "0"
}
}Tags
x402
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