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Vextorium ERC-20 Approval Revocation Transaction Builder
x402
Vextorium ERC-20 Approval Revocation Transaction Builder is a paid API for AI agents from api.vextorium.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-16).
Builds the unsigned transaction calldata to revoke a spender's ERC-20 token approval (approve(spender, 0)) — ready to sign and broadcast, nothing is sent on-chain.
Price / call$0.003
Success—
StatusUnknown
How this service works
Build the transaction that revokes a contract's permission over an ERC-20 token (approve(spender, 0)): target and calldata ready to sign in your wallet. Nothing is sent.
Output
A JSON object containing: the target token contract address (`para`), the full hex-encoded calldata (`datos`) for approve(address,uint256) with amount=0, the ETH value to send (always '0'), the function signature string, the decoded arguments array, and a human-readable note reminding the user to sign and send the transaction from the wallet that originally granted the permission.
Example use cases
Revoke DEX router token allowance
“I want to remove Uniswap's permission to spend my USDC — give me the transaction data to set the approval for 0x2626664c2603336E57B271c5C0b26F421741e481 to zero on the USDC contract at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.”
Security audit post-hack revocation
“A protocol I used was just exploited. Build me the calldata to revoke their contract at 0xAbCd1234...5678 from spending my DAI at 0x6B175474E89094C44Da98b954EedeAC495271d0F so I can sign and broadcast it immediately.”
Batch allowance cleanup workflow
“I'm cleaning up old token approvals — can you generate the unsigned approve(spender,0) transaction for the old bridge contract 0xAaaa...1111 on my WETH token at 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2?”
Technical details
Endpoint
POSThttps://api.vextorium.com/revocar-aprobacion-pago?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to programmatically construct a revoke-approval transaction without connecting a wallet to a UI. Ideal for agents automating wallet security workflows, post-exploit remediation bots, or any flow that needs raw calldata for approve(spender, 0) on ERC-20 tokens deployed on EVM chains like Base or Ethereum. Prefer this over manual ABI encoding when you want a simple, paid REST call that returns ready-to-sign target + calldata.
Side effects
- Invalid or malformed token address returns an error
- Invalid or malformed spender (gastador) address returns an error
- Non-ERC-20 contract address may produce calldata that reverts on-chain
- Network errors or upstream timeout return a 5xx response
- Missing required fields (token or gastador) return a 400-level validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| token | string | |
| gastador | string |
Output
Schema · Response
{
"type": "json",
"example": {
"nota": "Firma y envía esta transacción desde la wallet que dio el permiso.",
"para": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"datos": "0x095ea7b30000000000000000000000002626664c2603336e57b271c5c0b26f421741e4810000000000000000000000000000000000000000000000000000000000000000",
"valor": "0",
"funcion": "approve(address,uint256)",
"argumentos": [
"0x2626664c2603336E57B271c5C0b26F421741e481",
"0"
]
}
}Tags
x402
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