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Revoke Calldata Builder
x402
Revoke Calldata Builder is a paid API for AI agents from 402.com.tr, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-13).
Builds the ready-to-sign revoke transaction (contract address + calldata for approve(spender,0)) and reads the live current allowance for a token/spender pair on Base.
Price / call$0.02
Success—
StatusUnknown
How this service works
approval-advisor tells you WHAT to revoke; this builds the HOW: the ready-to-sign transaction (to + calldata) for approve(spender, 0) on a token, plus the live current allowance read from Base (flags unlimited, or 'already revoked'). Hand the result straight to a wallet or agent signer — the action half of approval hygiene.
Output
Returns the destination contract address (to) and hex calldata encoding approve(spender, 0) ready for signing, plus the live current allowance value fetched from Base mainnet — flagged as unlimited if it equals max uint256, or marked as already revoked if it is zero.
Example use cases
Revoke unlimited DeFi protocol approval
“I gave Uniswap unlimited access to my WETH — build me the calldata to revoke that approval for token 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 and spender 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D, and tell me if the allowance is still active.”
Pre-sign approval hygiene before transferring wallet
“Before I hand off this wallet, I need to revoke every risky approval. Start with token 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 and spender 0x3154Cf16ccdb4C6d922629664174b904d80F2C35 — give me the ready-to-sign revoke transaction and confirm the current allowance amount.”
Automated revoke after approval-advisor flagged a spender
“The approval advisor just flagged spender 0xDEF1C0ded9bec7F1a1670819833240f027b25EfF on my USDC token 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 as risky — build the approve-zero calldata so I can sign and broadcast it right away.”
Technical details
Endpoint
GEThttps://402.com.tr/api/x402/revoke-builderWhen to prefer
Choose this endpoint when you already know which token/spender pair to revoke (e.g. after running approval-advisor) and need the exact signed-ready calldata plus a live allowance confirmation — it bridges the gap between identifying a risky approval and actually executing the revocation, saving you from manually encoding approve(spender,0) calldata.
Side effects
- Invalid token contract address returns an error or zero response
- Invalid spender address format causes a 400-level error
- Token contract does not implement ERC-20 approve, causing calldata generation failure
- Wallet address omitted means live allowance cannot be read
- RPC read failure on Base may cause allowance lookup to timeout
- Unrecognized contract ABI may return malformed calldata
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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