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ETH Mainnet ERC-20 Allowance
x402
ETH Mainnet ERC-20 Allowance is a paid API for AI agents from ari001.tailb4ac3a.ts.net, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).
Reads the on-chain ERC-20 token allowance on Ethereum mainnet for a given token, owner, and spender address triple.
Price / call$0.002
Success—
StatusUnknown
How this service works
Ethereum mainnet ERC-20 allowance. Takes query parameters token (ERC-20 contract, 0x + 40 hex), owner (0x + 40 hex) and spender (0x + 40 hex). Returns the raw allowance read from the contract.
Output
Returns the raw uint256 allowance value representing the maximum number of token units the spender is permitted to transfer on behalf of the owner, as currently recorded in the ERC-20 contract's storage on Ethereum mainnet.
Example use cases
Pre-swap approval audit
“Before I try to swap on Uniswap, check whether the router at 0xE592427A0AEce92De3Edee1F18E0157C05861564 is already approved to spend my USDC (0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48) from 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on Ethereum mainnet.”
Token approval security review
“I want to audit my Ethereum wallet 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B — what's the current DAI (0x6B175474E89094C44Da98b954EedeAC495271d0F) allowance granted to the Maker DSProxy contract at 0x82a998C9dE88b6F49c25fb56C3b7e67a8F77d6e?”
DeFi protocol risk monitoring
“Check the WETH allowance on Ethereum mainnet — how many tokens from owner 0x47ac0Fb4F2D84898e4D9E7b4DaB3C24507a6D503 has the Aave lending pool at 0x7d2768dE32b0b80b7a3454c06BdAc94A69DDc7A9 been approved to spend for token 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2?”
Technical details
Endpoint
GEThttps://ari001.tailb4ac3a.ts.net/v1/ventures/x402_eth_reads_v1/eth_mainnet_erc20_allowance?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need the ERC-20 allowance specifically on Ethereum mainnet (not Base, Gnosis, or other chains). A sibling endpoint covers Base. Prefer this over generic RPC calls when you want a clean REST interface without manually encoding eth_call ABI data. Ideal for pre-transaction approval checks, wallet audits, and DeFi risk monitoring on mainnet.
Side effects
- Invalid or malformed Ethereum address (not 0x + 40 hex) returns a 400 validation error
- Token address is not a deployed ERC-20 contract — call may revert or return zero
- Network connectivity issues with the Ethereum node result in a 5xx error
- Rate limiting or payment failure at $0.002 per call may cause request rejection
- Allowance may be stale if read during a pending state-change transaction
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Tags
x402
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