> ## Documentation Index
> Fetch the complete documentation index at: https://docs.spirals.so/llms.txt
> Use this file to discover all available pages before exploring further.

# ⭐ Key Functions

### Deposit

Deposits ERC-20 asset into token vault on behalf of receiver who receives the
gTokens minted.

```
/**
 * @dev Function to handle a deposit of an underlying asset to the vault.
 *  Deploys the deposited assets to the yield strategy and mints new gTokens.
 * @param _amount amount of underlying asset to deposit
 * @param _receiver address to receive gTokens
*/
function deposit(
    uint256 _amount,
    address _receiver
) external
```

<Note>
  Make sure you approve the vault contract to spend this amount before calling
  deposit.
</Note>

### Withdraw

Withdraws ERC-20 asset from token vault into the receiver address. gTokens are
burned from the owner address.

```
/**
 * @dev Function to withdraw underlying asset from vault. This usually involves
 *  converting the yield asset to the underlying asset first.
 * @param _amount amount of underlying asset to withdraw
 * @param _recevier address receiving asset withdraw from vault
 * @param _owner address to burn gTokens from
*/
function withdraw(
    uint256 _amount,
    address _receiver,
    address _owner
) external
```

### Utility Methods

Returns the amount of yield attributable to a gToken address holder. Denominated
in asset.

```
/**
 * @dev Function returning the yield associated with a user on the vault
 * @param _owner address owning the gTokens
*/
function getYield(
    address _owner
) external view returns (uint256)
```

Returns the amount of yield attributable to a gToken address holder. Denominated
in asset.

```
/**
 * @dev Function returning the APY associated with the vault's
 * underlying yield strategy, 18 decimals.
*/
function getAPY() external view returns (uint256)
```

Converts an amount of the asset to its equivalent in the yield asset (ex: 1 ETH
-> 0.8 rETH).

```
/**
 * @dev Function converting amount of asset to yield asset
 * @param _amount amount of asset
*/
function convertToYieldAsset(
    address _amount
) external view returns (uint256)
```

Converts an amount of the yield asset to its equivalent in the asset (ex: 0.8
rETH -> 1 ETH).

```
/**
 * @dev Function converting amount of yield asset to asset
 * @param _amount amount of yield asset
*/
function convertToAsset(
    address _amount
) external view returns (uint256)
```

### Other

* All ERC-20 methods (`transfer`, `transferFrom`, `balanceOf`, etc.)

* If underlying asset is a native token (ex: ETH), then there is also another
  method available with the following signature:

```
/**
 * @dev Function to handle a deposit of a native token to the vault
 * @param _receiver address to receive gTokens
*/
function depositETH(
    address _receiver
) external payable
```