Approval Expiry Scheduler

WHAT IT DOES

Approval Expiry Scheduler lets you grant token allowances that are not permanent. Instead of leaving an approval open indefinitely, you set an amount and a duration—the tool schedules a revocation transaction to reset the allowance to zero after that time. You see a live countdown until expiry, and the revocation is submitted automatically when the timer runs out. This reduces the window during which a spender could use your allowance, giving you more control over your token approvals.

HOW TO USE

Connect your EVM wallet and select the network. Enter the token contract address, the spender address you want to approve, and the amount in wei. Set the expiry time in minutes (1 to 1440). Click "Schedule approval"—your wallet will prompt you to sign the approval transaction. Once confirmed, the tool displays the transaction details and starts a countdown. When the countdown reaches zero, it automatically submits a revocation transaction to set the allowance to 0. You can cancel the scheduled revocation at any time using the "Cancel scheduled revoke" button.

TECHNICAL MECHANISM

Standard ERC‑20 approve() does not support on‑chain expiry. This tool works by issuing two transactions: the initial approve(spender, amount) and a scheduled follow‑up approve(spender, 0). The scheduling is client‑side: a timer tracks the remaining time and triggers the revocation when it expires. The revocation transaction is submitted through your connected wallet and must be confirmed on‑chain. The tool uses receipt.effectiveGasPrice for accurate gas reporting (post‑EIP‑1559) and provides a visual progress bar during the countdown. If the revocation fails (e.g., due to gas issues), the tool alerts you and keeps the schedule state for manual intervention.

WHAT IT CANNOT SEE

This tool cannot enforce expiry on‑chain for standard approve()—the expiry is entirely client‑managed. If the revocation transaction is not mined (because the wallet is offline, gas is insufficient, or the network is congested), the approval remains active. It cannot detect or cancel approvals that have already been used in pending transactions. Non‑standard token implementations (e.g., permit, proxy‑based allowances) are not supported. The tool also does not monitor approvals across multiple chains or tokens simultaneously—each approval must be scheduled separately.

PLEASE NOTE

This is a convenience tool, not a guaranteed security mechanism. Always verify your approvals on‑chain after the expiry period, especially for high‑value assets. The tool does not store any data; all state is kept in memory and resets on page reload. Ensure you have enough native tokens (ETH, BNB, MATIC, etc.) to pay for both the approval and the revocation transaction. EVM chains only.