What is Token Approval?

A token approval is a permission your wallet gives to a smart contract, allowing it to spend a particular token on your behalf. Many DeFi actions, such as swapping on a DEX, require an approval first so the contract can move your tokens when you trade. Approvals can be limited to an exact amount or, dangerously, set to unlimited.

This matters because an approval is a standing permission that persists after the transaction. If you grant an unlimited approval to a malicious or later-compromised contract, it can drain that token whenever it wants, without asking again.

Example: to swap a stablecoin on a DEX, you first approve the DEX contract to spend it; if you approve an unlimited amount, that permission stays active until you revoke it.

Safety note: prefer approving only the amount you need, review what each approval grants, and periodically check and revoke old or unlimited approvals using a trusted approval-checker. A malicious approval is how many wallet-drainer scams actually steal funds, even without ever touching your seed phrase. Related terms include revoke, wallet-drainer, smart contract, and allowance.