Flash Loans


Since the Vault holds all tokens for all pools, the consolidated token balances are available as Flash Loans.

Example Code

pragma solidity ^0.7.0;

* "@balancer-labs/v2-interfaces/contracts" is refering to  "balancer-v2-monorepo/pkg/interfaces/contracts"
import {IVault} from "@balancer-labs/v2-interfaces/contracts/vault/IVault.sol";
import {IFlashLoanRecipient} from "@balancer-labs/v2-interfaces/contracts/vault/IFlashLoanRecipient.sol";
import {IERC20} from "@balancer-labs/v2-interfaces/contracts/solidity-utils/openzeppelin/IERC20.sol";

contract FlashLoanRecipient is IFlashLoanRecipient {
    IVault private constant vault = IVault(0xBA12222222228d8Ba445958a75a0704d566BF2C8);

    function makeFlashLoan(IERC20[] memory tokens, uint256[] memory amounts, bytes memory userData) external {
        vault.flashLoan(this, tokens, amounts, userData);

    function receiveFlashLoan(
        IERC20[] memory tokens,
        uint256[] memory amounts,
        uint256[] memory feeAmounts,
        bytes memory userData
    ) external override {
        require(msg.sender == address(vault));

        // This contract now has the funds requested.

        // Your logic goes here...

            At the end of your logic above, this contract owes
            the flashloaned amounts + feeAmounts.
            Therefore ensure your contract has enough to repay these amounts.

        // Return loan
        for (uint256 i = 0; i < tokens.length; i++) {
            tokens[i].transfer(address(vault), amounts[i] + feeAmounts[i]);