> For the complete documentation index, see [llms.txt](/llms.txt).

# Advanced Permissions reference

When [executing on a MetaMask user's behalf](/smart-accounts-kit/development/guides/advanced-permissions/execute-on-metamask-users-behalf/), you can request the following permission types for ERC-20 token and native token transfers. Learn [how to use Advanced Permissions types](/smart-accounts-kit/development/guides/advanced-permissions/use-permissions/erc20-token/).

## ERC-20 token permissions[​](#erc-20-token-permissions "Direct link to ERC-20 token permissions")

### ERC-20 allowance permission[​](#erc-20-allowance-permission "Direct link to ERC-20 allowance permission")

Ensures a fixed ERC-20 token allowance. Transfers are allowed until the total transferred amount reaches the allowance amount.

#### Parameters[​](#parameters "Direct link to Parameters")

| Name            | Type    | Required | Description                                                            |
| --------------- | ------- | -------- | ---------------------------------------------------------------------- |
| tokenAddress    | Address | Yes      | The ERC-20 token contract address.                                     |
| allowanceAmount | bigint  | Yes      | The maximum total amount of tokens that can be transferred.            |
| startTime       | number  | No       | The start timestamp in seconds. The default is the current time.       |
| justification   | string  | No       | A human-readable explanation of why the permission is being requested. |

#### Example[​](#example "Direct link to Example")

```
import { parseUnits } from 'viem'

const currentTime = Math.floor(Date.now() / 1000)
const expiry = currentTime + 604800

const permission = {
  type: 'erc20-token-allowance',
  data: {
    tokenAddress: '0x1c7D4B196Cb0C7B01d743Fbc6116a902379C7238',
    allowanceAmount: parseUnits('50', 6),
    startTime: currentTime,
    justification: 'Permission to transfer up to 50 USDC in total',
  },
  isAdjustmentAllowed: true,
}

```

### ERC-20 periodic permission[​](#erc-20-periodic-permission "Direct link to ERC-20 periodic permission")

Ensures a per-period limit for ERC-20 token transfers. At the start of each new period, the allowance resets.

#### Parameters[​](#parameters-1 "Direct link to Parameters")

| Name           | Type    | Required | Description                                                            |
| -------------- | ------- | -------- | ---------------------------------------------------------------------- |
| tokenAddress   | Address | Yes      | The ERC-20 token contract address as a hex string.                     |
| periodAmount   | bigint  | Yes      | The maximum amount of tokens that can be transferred per period.       |
| periodDuration | number  | Yes      | The duration of each period in seconds.                                |
| startTime      | number  | No       | The start timestamp in seconds. The default is the current time.       |
| justification  | string  | No       | A human-readable explanation of why the permission is being requested. |

#### Example[​](#example-1 "Direct link to Example")

```
import { parseUnits } from 'viem'

const currentTime = Math.floor(Date.now() / 1000)
const expiry = currentTime + 604800

const permission = {
  type: 'erc20-token-periodic',
  data: {
    tokenAddress: '0x1c7D4B196Cb0C7B01d743Fbc6116a902379C7238',
    periodAmount: parseUnits('10', 6),
    periodDuration: 86400,
    justification: 'Permission to transfer 10 USDC every day',
  },
  isAdjustmentAllowed: true,
}

```

### ERC-20 stream permission[​](#erc-20-stream-permission "Direct link to ERC-20 stream permission")

Ensures a linear streaming transfer limit for ERC-20 tokens. Token transfers are blocked until the defined start timestamp. At the start, a specified initial amount is released, after which tokens accrue linearly at the configured rate, up to the maximum allowed amount.

#### Parameters[​](#parameters-2 "Direct link to Parameters")

| Name            | Type    | Required | Description                                                                 |
| --------------- | ------- | -------- | --------------------------------------------------------------------------- |
| tokenAddress    | Address | Yes      | The ERC-20 token contract address.                                          |
| initialAmount   | bigint  | No       | The initial amount that can be transferred at start time. The default is 0. |
| maxAmount       | bigint  | No       | The maximum total amount that can be unlocked. The default is no limit.     |
| amountPerSecond | bigint  | Yes      | The rate at which tokens accrue per second.                                 |
| startTime       | number  | No       | The start timestamp in seconds. The default is the current time.            |
| justification   | string  | No       | A human-readable explanation of why the permission is being requested.      |

#### Example[​](#example-2 "Direct link to Example")

```
import { parseUnits } from 'viem'

const currentTime = Math.floor(Date.now() / 1000)
const expiry = currentTime + 604800

const permission = {
  type: 'erc20-token-stream',
  data: {
    tokenAddress: '0x1c7D4B196Cb0C7B01d743Fbc6116a902379C7238',
    amountPerSecond: parseUnits('0.1', 6),
    initialAmount: parseUnits('1', 6),
    maxAmount: parseUnits('2', 6),
    startTime: currentTime,
    justification: 'Permission to use 0.1 USDC per second',
  },
  isAdjustmentAllowed: true,
}

```

## Native token permissions[​](#native-token-permissions "Direct link to Native token permissions")

### Native token allowance permission[​](#native-token-allowance-permission "Direct link to Native token allowance permission")

Ensures a fixed native token allowance. Transfers are allowed until the total transferred amount reaches the allowance amount.

#### Parameters[​](#parameters-3 "Direct link to Parameters")

| Name            | Type   | Required | Description                                                            |
| --------------- | ------ | -------- | ---------------------------------------------------------------------- |
| allowanceAmount | bigint | Yes      | The maximum total amount of tokens that can be transferred.            |
| startTime       | number | No       | The start timestamp in seconds. The default is the current time.       |
| justification   | string | No       | A human-readable explanation of why the permission is being requested. |

#### Example[​](#example-3 "Direct link to Example")

```
import { parseEther } from 'viem'

const currentTime = Math.floor(Date.now() / 1000)
const expiry = currentTime + 604800

const permission = {
  type: 'native-token-allowance',
  data: {
    allowanceAmount: parseEther('0.05'),
    startTime: currentTime,
    justification: 'Permission to transfer up to 0.05 ETH in total',
  },
  isAdjustmentAllowed: true,
}

```

### Native token periodic permission[​](#native-token-periodic-permission "Direct link to Native token periodic permission")

Ensures a per-period limit for native token transfers. At the start of each new period, the allowance resets.

#### Parameters[​](#parameters-4 "Direct link to Parameters")

| Name           | Type   | Required | Description                                                            |
| -------------- | ------ | -------- | ---------------------------------------------------------------------- |
| periodAmount   | bigint | Yes      | The maximum amount of tokens that can be transferred per period.       |
| periodDuration | number | Yes      | The duration of each period in seconds.                                |
| startTime      | number | No       | The start timestamp in seconds. The default is the current time.       |
| justification  | string | No       | A human-readable explanation of why the permission is being requested. |

#### Example[​](#example-4 "Direct link to Example")

```
import { parseEther } from 'viem'

const currentTime = Math.floor(Date.now() / 1000)
const expiry = currentTime + 604800

const permission = {
  type: 'native-token-periodic',
  data: {
    periodAmount: parseEther('0.001'),
    periodDuration: 86400,
    startTime: currentTime,
    justification: 'Permission to use 0.001 ETH every day',
  },
  isAdjustmentAllowed: true,
}

```

### Native token stream permission[​](#native-token-stream-permission "Direct link to Native token stream permission")

Ensures a linear streaming transfer limit for native tokens. Token transfers are blocked until the defined start timestamp. At the start, a specified initial amount is released, after which tokens accrue linearly at the configured rate, up to the maximum allowed amount.

#### Parameters[​](#parameters-5 "Direct link to Parameters")

| Name            | Type   | Required | Description                                                                 |
| --------------- | ------ | -------- | --------------------------------------------------------------------------- |
| initialAmount   | bigint | No       | The initial amount that can be transferred at start time. The default is 0. |
| maxAmount       | bigint | No       | The maximum total amount that can be unlocked. The default is no limit.     |
| amountPerSecond | bigint | Yes      | The rate at which tokens accrue per second.                                 |
| startTime       | number | No       | The start timestamp in seconds. The default is the current time.            |
| justification   | string | No       | A human-readable explanation of why the permission is being requested.      |

#### Example[​](#example-5 "Direct link to Example")

```
import { parseEther } from 'viem'

const currentTime = Math.floor(Date.now() / 1000)
const expiry = currentTime + 604800

const permission = {
  type: 'native-token-stream',
  data: {
    amountPerSecond: parseEther('0.0001'),
    initialAmount: parseEther('0.1'),
    maxAmount: parseEther('1'),
    startTime: currentTime,
    justification: 'Permission to use 0.0001 ETH per second',
  },
  isAdjustmentAllowed: true,
}

```