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ERC20 Flash

This project implements ERC-3156 wrappers for the flash loan functionality of dYdX, Aave, Uniswap and Yield.

Contracts deployed

Mainnet

So far, only the dYdX wrapper has been deployed, to allow for a degree of testing in mainnet. Please raise an issue if you would like to test any of the other wrappers. All wrappers will be deployed in mainnet no later than the date in which ERC3156 progresses to a Final state.

Lender Lender Address Commit
DYDX 0x6bdC1FCB2F13d1bA9D26ccEc3983d5D4bf318693 5493629
Uniswap v2 0x28721b58c17A106a4846ACf4e751ac3a4b670Cbd e9f4cdf

Fantom

Lender Contract Lender Address Commit
Uniswap v2 0xa89a83890Cc5d43D710846cEFCb4a41007a37347 e9f4cdf

Kovan

In all real use cases, you will have to create your own contract to take flashLoans, calling the flashLoan function on an ERC3156 compliant lender (or one of the wrappers in this repo), and implementing the onFlashLoan callback.

However, you can use FlashBorrower to kick the tires. You can give to the flashBorrow function the address of an ERC3156 compliant lender (such as any of the wrappers in this repo), the address of a supported ERC20 token (which for wrappers depends on the underlying lender such as Aave) and a loan value. Upon execution a flash loan will happen, which you can examine in etherscan.io or tenderly.co. You will need to have transferred to FlashBorrower enough of the ERC20 being borrowed beforehand to pay for the fees.

Lender Contract Lender Address
FlashBorrower 0x5e3538099b9d19Dc8EB13cb1AD2b0e93D2cC2EbB
FlashMinter 0xC8df3958bb0D68e22e4d974CdA71d73A4e7E73b9
FlashLender 0xeef77EAE62e80F5F56b85Be318B57BF1470874F5
AaveERC3156 0xC355Fb535757B069D84B3bB01c27240DF973FBa2
DYDXERC3156 0xf1E70c817C82975Dfb6a0B7AB65b803f871E2c4E
UniswapERC3156 0x353939fcA37c1782512229d5D4f0d3E83Bf46B2C
YieldDaiERC3156 0x8E1ceabD0996bbDd15E611D26d333b8e9d684a27
YieldFYDaiERC3156 0x2F01fa8f4377682018B74B696933528ba03f1eb0

Tested currencies

The flash loans have been tested with the ERC20 tokens below, but should work for any tokens that the underlying lenders make available.

Lender Contract Currency
FlashMinter FlashMinter - 0x1e198e90c7166f7f9fD24b9D7A0451D7AeE78a3F
FlashLender, AaveERC3156, DYDXERC3156, UniswapERC3156 WETH9 - 0xd0A1E359811322d97991E03f863a0C30C2cF029C
FlashLender, YieldDaiERC3156, UniswapERC3156 DAI - 0x4F96Fe3b7A6Cf9725f59d353F723c1bDb64CA6Aa
DYDXERC3156 DAI - 0xC4375B7De8af5a38a93548eb8453a498222C4fF2
AaveERC3156 DAI - 0xFf795577d9AC8bD7D90Ee22b6C1703490b6512FD
YieldFYDaiERC3156 FYDAI - 0x6B166d6325586c86B44f01509Fc64e649DCfE7C4, 0x42AA68930d4430E2416036966983E6c9Fe8Ff2f8, 0x2b67866649AFcEFC63870E02EdefC318fd8760D3, 0x02B06417A3e3CB391970C6074AbcF2745a60b880, 0x6Abb65246346b2A52Faed338cB18880e70A57Cf8

Sample Execution

Let's say you want to test a flash loan of 10 DAI from Uniswap using FlashBorrower and the UniswapERC3156 wrapper.

  1. Head to the Flash Borrower contract
  2. Connect via Web3 and expand '1. flashBorrow'
  3. Input the following:
  lender: 0xeBe2432d4b8C59F33674F6076ddeE8643B8039d1
  token: 0x4F96Fe3b7A6Cf9725f59d353F723c1bDb64CA6Aa
  value: 10000000000000000000
  1. Then click Write to execute.
  2. If all went well it should look like this.

Flash Borrower needs to have enough of the borrowed token to pay for the flash loan fees.

  1. Check the fee amount with the flashFee function, the token is DAI (0x4F96Fe3b7A6Cf9725f59d353F723c1bDb64CA6Aa).
  2. Check the DAI balance of flashBorrower (0xeeb0c120bF35fB0793b1c7d0D93230e552020398) balanceOf function of the DAI contract.
  3. If FlashBorrower doesn't have enough DAI to pay for the loan fees, go to Uniswap and making sure that you are in Kovan, buy some DAI by address (0x4F96Fe3b7A6Cf9725f59d353F723c1bDb64CA6Aa) and send it to the FlashBorrower (0xeeb0c120bF35fB0793b1c7d0D93230e552020398).

Things to note

Flash loan basics still apply under this wrapper i.e.:

  • If you're flashing 100 DAI @ 9bps/flash, make sure there's at least 100 + 0.09 DAI on the contract by the end of the transaction
  • Native flash fees as at 31st Dec 2020 are: Aave 9bps, Uniswap 30 bps, dYdX 2 Wei, Yield 2.5 bps (time variant)
  • Flash lenders generally have significantly reduced liquidity on kovan testnet, so if your tx is reverting, check whether you're requesting an amount higher than their respective testnet reserves
  • Different protocols use different versions of the same token on kovan testnet, so make sure you pick the right one from above based on lender. This isn't an issue on mainnet.