# Revoke Allowance

When using dapps like Uniswap, OpenSea or a custom smart contract, you have to grant them permission to spend your tokens and NFTs, for example if you want to execute a swap function. This is called an allowance. If you don't revoke these allowances, the dapp can spend your tokens forever. Take back control by revoking your allowances.<br>

### &#x20;<mark style="background-color:blue;">Parameters</mark>&#x20;

<table><thead><tr><th width="183.33333333333331">Parameter name</th><th width="97">Type</th><th>Description</th></tr></thead><tbody><tr><td>Token contract</td><td>Text</td><td>Token that was used to be approved, for example USDC or an NFT contract</td></tr><tr><td>Spender</td><td>Text</td><td>Smart Contract address that the allowance was given to, for example the router contract from Uniswap. It also can be another user Wallet Address, because it is possible to give allowance to a wallet address as-well.</td></tr><tr><td>Gas Parameters</td><td>Number</td><td>The gas parameters are optional, use it only if you know what you are doing and you really need it.</td></tr></tbody></table>

### &#x20;<mark style="background-color:blue;">Events</mark>&#x20;

<table><thead><tr><th width="146">Event name</th><th>Description</th></tr></thead><tbody><tr><td>Revoked</td><td>Triggered when the allowance was successfully revoked</td></tr></tbody></table>

Additionally, see [common events and states](https://docs.novabloq.com/web3-metamask/elements-details/web3-and-metamask/..#common-events) for tx hash or error event.