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

# Swap Tokens for HBAR

> Swap HTS fungible tokens for HBAR

Below are three methods available to swap tokens for tokens:

* [Swap exact tokens for HBAR](/v/developer/saucerswap-v1/swap-operations/swap-tokens-for-hbar#swap-exact-tokens-for-hbar)
* [Swap tokens for exact HBAR](/v/developer/saucerswap-v1/swap-operations/swap-tokens-for-hbar#swap-tokens-for-exact-hbar)
* [Swap exact tokens supporting custom fees for HBAR](/v/developer/saucerswap-v1/swap-operations/swap-tokens-for-hbar#swap-exact-tokens-supporting-custom-fees-for-hbar)

<Info>
  **Contract ID:** [SaucerSwapV1RouterV3](https://hashscan.io/mainnet/contract/0.0.3045981)
</Info>

<Info>
  The **swapExactTokensForETH** and **swapTokensForExactETH** function trades in HBAR but derives its name from Uniswap on Ethereum. This name was kept to simplify integration for developers versed in Uniswap tools.
</Info>

<Note>
  Granting an spender allowance to the router contract **is required** when the input token is not native HBAR for security reasons enforced at the native code layer. Ensure that the allowance amount is in token's smallest unit.
</Note>

<Note>
  Consider the token's decimal places when determining input amounts.

  The input values should be in the token's smallest unit. For the SAUCE token, which has 6 decimal places, an input of 123.45 SAUCE should be entered as 123450000 (123.45 multiplied by 10^6).
</Note>

<Tip>
  When providing HBAR in the path array, use the wrapped HBAR token ID ([WHBAR](https://hashscan.io/mainnet/token/0.0.1456986)).
</Tip>

## Swap Exact Tokens for HBAR

Swap an exact amount of tokens for a minimum HBAR amount.

Solidity function name: **swapExactTokensForETH**

| Parameter Name             | Description                                              |
| -------------------------- | -------------------------------------------------------- |
| *uint amountIn*            | The input token amount in its smallest unit              |
| *uint amountOutMin*        | The minimum token amount to receive in its smallest unit |
| *address\[] calldata path* | An ordered list of token EVM addresses                   |
| *address to*               | EVM address for the token recipient                      |
| *uint deadline*            | Deadline in Unix seconds                                 |

<CodeGroup>
  ```solidity IUniswapV2Router01.sol theme={null}
  function swapExactTokensForETH(
    uint amountIn,
    uint amountOutMin,
    address[] calldata path,
    address to,
    uint deadline
  ) external returns (uint[] memory amounts);
  ```

  ```solidity UniswapV2Router02.sol theme={null}
  function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
    external
    virtual
    override
    ensure(deadline)
    returns (uint[] memory amounts)
  {
    require(path[path.length - 1] == whbar, 'UniswapV2Router: INVALID_PATH');
    amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
    require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');

    safeTransferToken(
      path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
    );

    _swap(amounts, path, address(this));   
    safeApproveToken(whbar, WHBAR, amounts[amounts.length - 1]);  
    IWHBAR(WHBAR).withdraw(address(this), to, amounts[amounts.length - 1]);
  }
  ```
</CodeGroup>

<Warning>
  Set the minimum output token amount (**amountOutMin**) with caution.

  A high minimum might lead to a swap failure due to insufficient liquidity or rapid price movements. Conversely, setting the minimum too low can expose you to significant slippage, potentially resulting in a financial loss as you might receive far fewer tokens than expected.
</Warning>

### Code Overview

<Tabs>
  <Tab title="JavaScript SDK">
    **Resources:**

    * [SaucerSwap deployed contract IDs](/developerx/contract-deployments)
    * [Hedera JavaScript SDK](https://github.com/hashgraph/hedera-sdk-js)
    * [Token approve allowance](https://docs.hedera.com/hedera/sdks-and-apis/sdks/cryptocurrency/approve-an-allowance) &#x20;
    * [Calling a smart contract function](https://docs.hedera.com/hedera/sdks-and-apis/sdks/smart-contracts/call-a-smart-contract-function)

    ```typescript Typescript theme={null}
    import { 
      ContractFunctionParameters, 
      ContractExecuteTransaction,
      AccountAllowanceApproveTransaction,
      .. 
    } from '@hashgraph/sdk';

    //Client pre-checks:
    // - Router contract has spender allowance for the input token

    const params = new ContractFunctionParameters();
    params.addUint256(amountIn); //uint amountIn
    params.addUint256(amountOutMin); //uint amountOutMin
    params.addAddressArray(tokenPath); //address[] calldata path
    params.addAddress(toAddress); //address to
    params.addUint256(deadline); //uint deadline
        
    const response = await new ContractExecuteTransaction()
     .setContractId(routerContractId)
     .setGas(gasLim)
     .setFunction('swapExactTokensForETH', params)
     .execute(client);
     
    const record = await response.getRecord(client);
    const result = record.contractFunctionResult!;
    const values = result.getResult(['uint[]']);
    const amounts = values[0]; //uint[] amounts
    const finalOutputAmount = amounts[amounts.length - 1];
    ```
  </Tab>
</Tabs>

***

## Swap Tokens for Exact HBAR

Swap a maximum amount of tokens to receive an exact HBAR amount.

<CodeGroup>
  ```solidity IUniswapV2Router01.sol theme={null}
  function swapTokensForExactETH(
    uint amountOut,
    uint amountInMax,
    address[] calldata path,
    address to,
    uint deadline
  ) external returns (uint[] memory amounts);
  ```

  ```solidity UniswapV2Router02.sol theme={null}
  function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
    external
    virtual
    override
    ensure(deadline)
    returns (uint[] memory amounts)
  {
    require(path[path.length - 1] == whbar, 'UniswapV2Router: INVALID_PATH');
    amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
    require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
    safeTransferToken(
      path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
    );
    
    _swap(amounts, path, address(this));
    safeApproveToken(whbar, WHBAR, amounts[amounts.length - 1]);     
    IWHBAR(WHBAR).withdraw(address(this), to, amounts[amounts.length - 1]);
  }
  ```
</CodeGroup>

Function name: **swapTokensForExactETH**

| Parameter Name             | Description                                                  |
| -------------------------- | ------------------------------------------------------------ |
| *uint amountOut*           | The exact output HBAR amount to receive in its smallest unit |
| *uint amountInMax*         | The maximum allowed input amount in its smallest unit        |
| *address\[] calldata path* | An ordered list of token EVM addresses                       |
| *address to*               | EVM address for the token recipient                          |
| *uint deadline*            | Deadline in Unix seconds                                     |

<Warning>
  Set the maximum input token amount (**amountInMax**) with caution.

  A low maximum might lead to a swap failure if the required liquidity surpasses this limit or due to rapid price movements. Conversely, setting it too high can expose you to significant slippage, potentially leading to a financial loss as you might spend far more tokens than expected.
</Warning>

### Code Overview

<Tabs>
  <Tab title="JavaScript SDK">
    **Resources:**

    * [SaucerSwap deployed contract IDs](/developerx/contract-deployments)
    * [Hedera JavaScript SDK](https://github.com/hashgraph/hedera-sdk-js)
    * [Token approve allowance](https://docs.hedera.com/hedera/sdks-and-apis/sdks/cryptocurrency/approve-an-allowance) &#x20;
    * [Calling a smart contract function](https://docs.hedera.com/hedera/sdks-and-apis/sdks/smart-contracts/call-a-smart-contract-function)

    ```typescript Typescript theme={null}
    import { 
      ContractFunctionParameters, 
      ContractExecuteTransaction,
      AccountAllowanceApproveTransaction
      .. 
    } from '@hashgraph/sdk';

    //Client pre-checks:
    // - Router contract has spender allowance for the input token

    const params = new ContractFunctionParameters();
    params.addUint256(amountOut); //uint amountOut
    params.addUint256(amountInMax); //uint amountInMax
    params.addAddressArray(tokenPath); //address[] calldata path
    params.addAddress(toAddress); //address to
    params.addUint256(deadline); //uint deadline
        
    const response = await new ContractExecuteTransaction()
     .setContractId(routerContractId)
     .setGas(gasLim)
     .setFunction('swapTokensForExactETH', params)
     .execute(client);
     
    const record = await response.getRecord(client);
    const result = record.contractFunctionResult!;
    const values = result.getResult(['uint[]']);
    const amounts = values[0]; //uint[] amounts
    const finalInputAmount = amounts[0];
    ```
  </Tab>
</Tabs>

***

## Swap Exact Tokens Supporting Custom Fees for HBAR

Swap an exact amount of tokens, supporting HTS tokens with custom fees on token transfer, for a minimum HBAR amount.

Solidity function name: **swapExactTokensForETHSupportingFeeOnTransferTokens**

| Parameter Name             | Description                                              |
| -------------------------- | -------------------------------------------------------- |
| *uint amountIn*            | The input token amount in its smallest unit              |
| *uint amountOutMin*        | The minimum token amount to receive in its smallest unit |
| *address\[] calldata path* | An ordered list of token EVM addresses                   |
| *address to*               | EVM address for the token recipient                      |
| *uint deadline*            | Deadline in Unix seconds                                 |

<CodeGroup>
  ```solidity IUniswapV2Router02.sol theme={null}
  function swapExactTokensForETHSupportingFeeOnTransferTokens(
    uint amountIn,
    uint amountOutMin,
    address[] calldata path,
    address to,
    uint deadline
  ) external;
  ```

  ```solidity UniswapV2Router02.sol theme={null}
  function swapExactTokensForETHSupportingFeeOnTransferTokens(
    uint amountIn,
    uint amountOutMin,
    address[] calldata path,
    address to,
    uint deadline
  )
    external
    virtual
    override
    ensure(deadline)
  {
    require(path[path.length - 1] == whbar, 'UniswapV2Router: INVALID_PATH');
    uint startAmount = IERC20(whbar).balanceOf(address(this));
    safeTransferToken(
      path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn
    );
    _swapSupportingFeeOnTransferTokens(path, address(this));
    uint endAmount = IERC20(whbar).balanceOf(address(this));
    uint amountOut = endAmount.sub(startAmount);
    require(amountOut >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
    safeApproveToken(whbar, WHBAR, amountOut);
    IWHBAR(WHBAR).withdraw(address(this), to, amountOut);
  }
  ```
</CodeGroup>

<Warning>
  Set the minimum output token amount (**amountOutMin**) with caution.

  A high minimum might lead to a swap failure due to insufficient liquidity or rapid price movements. Conversely, setting the minimum too low can expose you to significant slippage, potentially resulting in a financial loss as you might receive far fewer tokens than expected.
</Warning>

### Code Overview

<Tabs>
  <Tab title="JavaScript SDK">
    **Resources:**

    * [SaucerSwap deployed contract IDs](/developerx/contract-deployments)
    * [Hedera JavaScript SDK](https://github.com/hashgraph/hedera-sdk-js)
    * [Token approve allowance](https://docs.hedera.com/hedera/sdks-and-apis/sdks/cryptocurrency/approve-an-allowance) &#x20;
    * [Calling a smart contract function](https://docs.hedera.com/hedera/sdks-and-apis/sdks/smart-contracts/call-a-smart-contract-function)

    ```typescript Typescript theme={null}
    import { 
      ContractFunctionParameters, 
      ContractExecuteTransaction,
      AccountAllowanceApproveTransaction,
      .. 
    } from '@hashgraph/sdk';

    //Client pre-checks:
    // - Router contract has spender allowance for the input token

    const params = new ContractFunctionParameters();
    params.addUint256(amountIn); //uint amountIn
    params.addUint256(amountOutMin); //uint amountOutMin
    params.addAddressArray(tokenPath); //address[] calldata path
    params.addAddress(toAddress); //address to
    params.addUint256(deadline); //uint deadline
        
    await new ContractExecuteTransaction()
     .setContractId(routerContractId)
     .setGas(gasLim)
     .setFunction('swapExactTokensForTokensSupportingFeeOnTransferTokens', params)
     .execute(client);
    ```
  </Tab>
</Tabs>