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ERC-20 Token Allowance Lookup
x402
ERC-20 Token Allowance Lookup is a paid API for AI agents from ai-data-marketplace-1042299154756.us-central1.run.app, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-13).
Looks up the current ERC-20 token spending allowance granted by an owner wallet to a spender address on Base, Ethereum, or Arbitrum.
Price / call$0.003
Success—
StatusUnknown
How this service works
Read the current ERC-20 allowance for an owner, spender, and token from a supported EVM network without signing or broadcasting.
Output
Returns a JSON object with the token symbol, a boolean indicating whether any approval exists (approval_present), the raw allowance as a string integer (allowance_raw), and the human-readable formatted allowance (allowance_formatted), along with a success flag.
Example use cases
Audit DeFi Protocol Token Approvals
“Can you check if Aave's lending pool contract 0x87870Bca3F3fD6335C3F4ce8392D69350B4fA4E2 has any USDC approval from my wallet 0x1234...abcd on Ethereum? I want to know the exact amount it's allowed to spend.”
Detect Unlimited Token Approvals
“Look up the USDT allowance that Uniswap's swap router 0xE592427A0AEce92De3Edee1F18E0157C05861564 has from wallet 0xDeAd...BeeF on Arbitrum — I'm trying to figure out if there's an unlimited approval I should revoke.”
Pre-transaction Allowance Check
“Before I proceed, can you verify whether the 1inch aggregator at 0x1111111254EEB25477B68fb85Ed929f73A960582 already has enough WETH allowance from wallet 0xBaAd...Face on Base to cover a 2 WETH swap?”
Technical details
Endpoint
GEThttps://ai-data-marketplace-1042299154756.us-central1.run.app/api/v1/erc20_allowanceWhen to prefer
Use this endpoint when you need a lightweight, pay-per-call lookup of ERC-20 token allowances across Base, Ethereum, or Arbitrum without setting up your own blockchain RPC infrastructure. Ideal for security audits, pre-transaction checks, and DeFi workflow automation where you need to verify approvals granted to a specific spender.
Side effects
- Invalid token contract address returns an error or empty result
- Unsupported chain identifier causes a bad request response
- Owner or spender address formatted incorrectly returns a failure
- Network timeout or RPC node unavailability may cause transient errors
- Token contract that does not implement ERC-20 allowance method may return an error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"symbol": "USDC",
"success": true,
"allowance_raw": "0",
"approval_present": false,
"allowance_formatted": "0.0"
}
}Tags
x402
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