Token approvals: what they are and how to revoke them

Many trades and dApps need permission to move a token from your address. That permission is an approval, also called an allowance. It is given to a contract — the spender — sometimes for an exact amount and sometimes without limit, and it stays in force until it is used up or revoked.

Approvals in Smartable's swaps

When a swap needs one, the approval is a separate confirmation, before the swap itself. Smartable approves the amount of that swap, not an unlimited allowance. It costs one approval per swap instead of one per token, but a standing permission can never reach more than the trade it was given for.

Seeing and revoking

Settings → Security → Token approvals lists the approvals that stand: the token, the spender, and whether the amount is limited or unlimited.

Revoking is a transaction on the network, so it pays a network fee, and it takes effect once the network confirms it.

What the list does not show

Only approvals made in this wallet, on this phone, are listed. Approvals you gave from a browser extension, another app, another phone — or before you restored this wallet here — are not in it, but they still stand on the network. To review those, use the token-approval page of a block explorer you trust, for the right network.

Before you approve anything

• Check the token, the spender and the amount. An unlimited approval to a contract you do not recognise is the thing to refuse.
• A signature can grant the same power as an approval. Some messages a site asks you to sign — permits and orders — authorise spending without a separate transaction. Read what a signature request says before you sign it.

Revoking removes a permission for the future. It does not reverse a transaction that has already happened.