When using a DApp, you may be asked to approve a transaction called an "Approve." This grants permission for the smart contract used by that DApp to move a specific token from your wallet. DApps use this permission, via the smart contract, to carry out actions like swaps and staking.
This mechanism itself is a basic feature of DeFi and isn't inherently bad. However, leaving this permission active for a malicious DApp, or one with poor security practices, is risky. If the contract is later hacked, or was designed from the start to drain funds, this permission could be exploited.
Unless you revoke it yourself, this permission remains active indefinitely.
Revoke.cash is a free security tool that lets you view a list of these permissions (approvals) and remove any you no longer need. It supports over 100 networks, including Ethereum, BNB Smart Chain, and Polygon.
Phishing clones impersonating Revoke.cash exist. Always make sure the URL is exactly revoke.cash before proceeding.
How to Use Revoke.cash
You can also access Revoke.cash directly from the browser inside the Avacus app. Copy the URL below, open a new tab from the "Browser" tab at the center of the bottom navigation bar, and go to the URL.
1. Connect Your Wallet, or Search by Address
Connect your wallet using "Connect Wallet" in the top right, or simply paste your wallet address into the search bar to view your approvals in read-only mode.
2. Select a Network
Select the network you'd like to check (Ethereum, BNB Smart Chain, Polygon, etc.). Once loading is complete, you'll see a list of the tokens and NFTs you've granted approvals for on that network.
3. Review Any Unfamiliar Approvals
Look through the list for approvals such as:
- DApps or contracts you've never used
- Services you've stopped using
- Approvals marked as "Unlimited"
"Unlimited" approvals are convenient, since you only need to sign once for repeated transactions — but if that contract is later hacked, more of your assets could be moved than you expected. Pay close attention to these.
4. Revoke the Approval
Tap the "Revoke" button next to any approval you'd like to remove. If you'd rather reduce the approved amount instead of removing it entirely, you can change the amount using the pencil icon.
Selecting "Revoke" will bring up a transaction approval screen in your wallet. Review the details and sign to complete the revocation.
Revoking an approval is recorded as a transaction on the blockchain, so — just like a regular transfer — a gas fee applies.
When to Check Your Approvals
- After connecting to an unfamiliar or new DApp
- When you hear news that a protocol you've used has been hacked
- When there are DApps or services you haven't used in a while
- When you feel you approved (signed) something without reviewing it carefully
Revoke.cash isn't a tool for recovering stolen assets — it's a preventative tool for stopping theft before it happens. We recommend making it a habit to check your approvals regularly, such as once a month.