Topic
What is a token approval?
Last reviewed:
- Quick fact 1
A token approval gives a smart contract permission to move certain tokens from your wallet.
Source: ethereum.org: How to revoke smart contract access to your crypto funds
- Quick fact 2
Approvals stay in place until you revoke them.
Source: ethereum.org: How to revoke smart contract access to your crypto funds
- Quick fact 3
Scam sites try to get you to sign approvals that let them take your tokens.
The short lesson
When you use an app on Ethereum and similar networks, the app often needs permission to move a token for you, for example to swap it. You give that permission by signing a token approval.
The catch: an approval can be for a set amount or for an unlimited amount. And it stays in place after you leave the app, until you take it back.
That is why approvals are a favorite tool of scammers. A fake airdrop or mint page asks you to “connect” and then sign. If you sign an approval for their contract, they can move your tokens later, without asking again. They never needed your seed phrase.
Safe habits:
- Read every wallet pop-up. If it says “approve,” “permit” or “set approval for all,” stop and ask why.
- Approve only what you need, on sites you reached yourself.
- Review and revoke old approvals. ethereum.org explains how.
- Use a separate wallet with little in it for trying new apps.
Related terms
Go deeper in Lesson 5: What a transaction is
Common questions
Is signing an approval the same as sending?
No, but it can let a contract send your tokens later without asking again.
How do I revoke an approval?
Use your wallet’s settings or a trusted approval checker for your network. Revoking is itself a transaction with a small fee.
What is “set approval for all”?
A permission that lets a contract move all your NFTs in a collection. Be very careful with it.
Can a drainer take my tokens without my seed phrase?
Yes, if you signed an approval or permit for its contract.