Time-Limited Token Approval Setter

WHAT IT DOES

Time-Limited Token Approval Setter lets you grant ERC-20 token allowances that are not permanent. Instead of leaving an infinite or large approval open indefinitely, you specify an amount and a duration (in minutes). The tool sets the approval, then schedules a follow‑up revocation transaction that resets the allowance to zero after the time elapses. This reduces the window during which a compromised or malicious spender could drain your tokens. You can also revoke manually at any time.

HOW TO USE

Connect your EVM wallet and select the network where your token is deployed. Enter the token contract address, the spender address you want to approve, and the approval amount in wei (the smallest unit). Set the expiry time in minutes — for example, 15 minutes for a short‑lived swap approval. Click "Set approval (with expiry)". Your wallet will prompt you to sign the approval transaction. After it confirms, the tool displays the current allowance and starts a countdown. When the time runs out, it automatically sends a second transaction to set the allowance to zero. You can also click "Revoke now" to cancel early.

TECHNICAL MECHANISM

Standard ERC‑20 approve() does not natively support time‑based limits; the allowance remains until it is changed or spent. This tool works around that by using two transactions: first, it calls approve(spender, amount) to grant the allowance. Second, it uses a client‑side timer to wait for the selected expiry duration, then it calls approve(spender, 0) to revoke. The revocation is submitted through the user's wallet and must be confirmed on‑chain. The tool checks the current allowance after each transaction to verify the state. If the revocation fails (e.g., due to gas issues or network congestion), it retries once after a short delay and notifies the user.

WHAT IT CANNOT SEE

This tool cannot enforce expiry on‑chain for standard approve() — the expiry is purely client‑managed. If the revocation transaction is not mined (because the user's wallet is offline, gas is insufficient, or the network is congested), the approval remains active. The tool cannot detect or cancel approvals that have already been used in a pending transaction. It does not support non‑EVM chains or tokens that use non‑standard approval patterns (e.g., permit, delegation, or proxy‑based allowances). It also cannot read off‑chain expiry signals or enforce limits set by other contracts.

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. Use at your own discretion and ensure you have enough native tokens (ETH, BNB, MATIC, etc.) to pay for both the approval and the subsequent revocation transaction.