What is checking token approvals?
- Author
- CRYPTO PORT Editorial
- Published
- Updated
- Reading time
- 5 min
In short
Approving a token grants a specific contract permission to move your funds. That permission stays in place until you revoke it. Reviewing your approvals periodically and revoking the unused or unlimited ones is one of the most effective habits in self-custody.
Key points
- A setting that lets a contract move tokens from your balance
- It stays active until you explicitly revoke it
- An unlimited approval can reach your whole balance
- Review the list regularly and revoke what you no longer use
Definition
A setting on ERC-20 style tokens that lets a named contract withdraw up to a given amount from your balance. It is the step before a swap or a deposit, and it persists until revoked.
Before you swap on a DEX or deposit into a lending market, you are asked to sign an approval. That is a separate action from the trade itself: it registers permission for the contract to pull tokens from your balance, usually with a very high cap set for convenience.
The trouble is that the permission outlives the trade. If a vulnerability is found in that contract later — or if it was malicious from the start — the door to your balance is still open. Most wallet-draining scams work by obtaining an approval, not by stealing a key.
You can review approvals through an explorer's approval view or a dedicated revocation tool. Start with counterparties you do not recognise, services you have stopped using, and anything with an unlimited cap. Revoking costs gas, so splitting a high-value wallet from a wallet you experiment with also helps.
Watch out for
- · Never enter a key or seed phrase into a site offering to revoke approvals for you
- · Revoking costs gas, so batch it when the network is quiet
- · Revoking stops future draws; it does not bring back what already moved