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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 ca-tax-api-mainnet.lxtap.workers.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-23).
Returns the ERC-20 allowance a spender has on Polygon PoS, including whether it is effectively unlimited, the owner's current balance, and the spendable amount right now.
Price / call$0.005
Success—
StatusUnknown
How this service works
Pay-per-call data for AI agents, paid in USDC on Base with x402: token risk checks (rug check) on Base, Ethereum, Arbitrum, Optimism, Polygon and Solana, onchain reads (balances, transactions, gas, contracts, NFTs, whale trades, new pools, ENS and Basenames), ECB exchange rates, and Canadian sales tax and business days.
Output
Returns the raw allowance granted by the owner to the spender, a boolean indicating whether the approval is effectively unlimited (max uint256), the owner's current ERC-20 token balance on Polygon PoS, and the effective amount the spender can move right now (the minimum of the allowance and the owner's balance).
Example use cases
DeFi protocol approval audit
“Check the USDC allowance that Uniswap's router 0xE592427A0AEce92De3Edee1F18E0157C05861564 has on Polygon PoS for my wallet 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B — is it set to unlimited, and how much can they actually move given my current balance? Token is 0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174.”
Wallet security allowance check
“I want to audit whether any contracts have been approved to spend more tokens than I intended from wallet 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B on Polygon PoS. Check the allowance for token 0x7ceB23fD6bC0adD59E62ac25578270cFf1b9f619 and spender 0x1111111254EEB25477B68fb85Ed929f73A960582 — is it effectively unlimited?”
Smart contract integration pre-check
“Before my app calls a swap on Polygon PoS, verify that spender 0xa5E0829CaCEd8fFDD4De3c43696c57F7D7A678ff has enough allowance from owner 0xDEAD000000000000000042069420694206942069 to move at least 500 USDC (token 0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174) — tell me the allowance, the owner's balance, and the effective spendable amount.”
Technical details
Endpoint
GEThttps://ca-tax-api-mainnet.lxtap.workers.dev/polygon/allowance?utm_source=zero.xyzWhen to prefer
Use this endpoint when you specifically need ERC-20 allowance data on the Polygon PoS network, including whether an approval is unlimited and the effective spendable amount factoring in the owner's balance. Prefer this over raw RPC calls when you want enriched, ready-to-use allowance intelligence rather than a raw uint256, and when operating on Polygon PoS (not Ethereum mainnet, Arbitrum, Base, or other chains).
Side effects
- Invalid Ethereum address format for token, owner, or spender returns a 400 validation error
- Token address that is not a deployed ERC-20 contract on Polygon PoS returns an error or zero values
- Polygon PoS RPC node unavailability causes a 502 or timeout
- Missing required query parameters (token, owner, or spender) returns a 400 error
- Payment not included or insufficient USDC causes a 402 Payment Required response
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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