> For the complete documentation index, see [llms.txt](https://superfluid.gitbook.io/superfluid/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://superfluid.gitbook.io/superfluid/developers/constant-flow-agreement-cfa/cfa-access-control-list-acl.md).

# Access Control List (ACL)

An approval layer for creating, updating, or deleting streams on another user’s behalf.

The Access Control List (ACL) allows any account (plain EOA or contract) to configure permissions for another account to create/update/delete streams on its behalf. 

It's basically the money streaming equivalent of the ERC20 approval mechanism!

<figure><img src="https://422548309-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MKEcOOf_qoYMObicyRu%2Fuploads%2FmYeq7MLWbSLJrtyj1AEX%2Fimage.png?alt=media&amp;token=f29ed525-8c1f-4ba4-ab62-e83a14077464" alt=""><figcaption><p><a href="https://docs.openzeppelin.com/contracts/2.x/api/token/erc20#IERC20-allowance-address-address-"><code>allowance</code></a>, <a href="https://docs.openzeppelin.com/contracts/2.x/api/token/erc20#IERC20-approve-address-uint256-"><code>approval</code></a>, and <a href="https://docs.openzeppelin.com/contracts/2.x/api/token/erc20#IERC20-transferFrom-address-address-uint256-"><code>transferFrom</code></a> are to ERC20 transfers as <code>getFlowOperatorData</code>, <code>updateFlowOperatorPermissions</code>, and <code>(create/update/delete)FlowByOperator</code> are to Superfluid streams.</p></figcaption></figure>

If you're checking out the functions ACL provides you, you'll want to understand the `flowRateAllowance` and `permissions` parameters.

## `flowRateAllowance` Parameter

You can think of `flowRateAllowance` as a tank. When you set `flowRateAllowance` in your [`updateFlowOperatorPermissions`](/superfluid/developers/constant-flow-agreement-cfa/cfa-access-control-list-acl/sdk-core/updateflowoperatorpermissions.md) call imagine you've filled up that tank to a level of your choosing for the `flowOperator` account.

That`flowOperator` account can spend its `flowRateAllowance` tank as it likes. Every time it **increases** a flow rate on your behalf, its `flowRateAllowance` tank is depleted by the amount of the increase.&#x20;

On the other side, actions that **decrease** your flow rate (updating a stream to a lower flow rate or deleting one) **don't affect** `flowRateAllowance`.&#x20;

If a `flowOperator`'s `flowRateAllowance` is too small for it to create/increase a flow, then its action is reverted. This entire dynamic is just like the ERC20 allowance mechanism! Here's an example to drive it home 👇

**Example:**

Let’s assume that we enable an operator to create and update streams with a flowRate allowance of 1000 tokens per month (which would be represented as a flow rate of `385802469135802` tokens per second). If our operator creates a stream on our behalf with a `flowRate` of 500 tokens per month, then the operator’s remaining `flowRateAllowance` becomes 500 tokens per month (`1000/month - 500/month`). Then, if our operator updates another one of our streams that is already outstanding by increasing our `flowRate` by 250 tokens per month, then our operator’s `flowRateAllowance` will decrease by another 250 tokens per month, leaving the remaining flowRateAllowance at 250 tokens per month (`500/month - 250/month`).

## `permissions` Parameter

The `permissions` value is a `uint256` from 1 to 7 representing a specific level of access that an operator gets over your streams. You pass in `permissions` when calling [`updateFlowOperatorPermissions`](/superfluid/developers/constant-flow-agreement-cfa/cfa-access-control-list-acl/sdk-core/updateflowoperatorpermissions.md).

| Permission Type           | Parameter Value |
| ------------------------- | --------------- |
| Create                    | 1               |
| Update                    | 2               |
| Create or Update          | 3               |
| Delete                    | 4               |
| Create or Delete          | 5               |
| Delete or Update          | 6               |
| Create, Update, or Delete | 7               |