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Token approvals: what they are and how to revoke them

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When you use a decentralized exchange or app with tokens like USDC, your wallet first asks you to approve the app. That approval lets the app’s smart contract move a token out of your wallet without asking again. It’s how these apps work, but it’s also one of the most common ways wallets get emptied.

Why approvals are risky

  • They don’t expire. An approval you gave two years ago still works today.
  • Many are unlimited. Apps often request permission to move any amount of a token, so you don’t have to approve again next time.
  • The app can change or be hacked. If the contract you approved is exploited, the attacker can use your old approval.
  • Scam sites ask for them on purpose. A fake airdrop or mint page asks you to “claim” something. The transaction you sign is really an approval for the scammer.

See what an unlimited approval exposes

Say you hold $10,000 in USDC and swap $200 through an app. With an unlimited approval, the app can still move the remaining $9,800, plus anything you add later, until you revoke it. With an exact-amount approval, the trade uses it up and nothing else is exposed.
Watch for signatures too. Some approvals don't cost gas and look like a harmless "sign this message" request. These are called permit signatures, and they can give the same power as a regular approval. If a site you don't fully trust asks you to sign, read what the wallet shows before you click.

How to check your approvals

  1. Open a reputable approval checker such as Revoke.cash or the token approval tool on the block explorer for your network (for Ethereum, Etherscan’s token approval checker).
  2. Type the address you want to check. You don’t need to connect your wallet just to look.
  3. Review the list. Look at which app each approval is for and whether the amount is unlimited.

How to revoke

  1. Connect your wallet to the checker you used, after making sure you typed its address yourself.
  2. Click Revoke next to any approval you don’t recognize or no longer use.
  3. Confirm in your wallet. Revoking is a normal transaction, so it costs a small gas fee on most networks.

Good habits

  • Revoke approvals for apps you’ve stopped using.
  • Check every few months, and right away after a suspicious signature.
  • When a wallet lets you, set a custom approval amount instead of unlimited.
  • Keep a separate “hot” wallet for trying new apps, with only what you need in it.
Revoking stops future losses. It can't undo a transfer that already happened. If funds are already gone, follow the steps in our scams guide.