LendPool

The LendPool contract is the main contract of the protocol. It exposes all the user-oriented actions that can be invoked using either Solidity or web3 libraries.

If you need development support, join the #developers channel on the Bend community Discord server.

LendPool methods deposit, borrow, withdraw and repay are only for ERC20 and ERC721, if you want to deposit, withdraw, borrow or repay using native ETH use WETHGateway instead, and if you want to borrow or repay using CryptoPunks as collaterals use PunkGateway.

Methods

deposit

function deposit(address asset, uint256 amount, address onBehalfOf, uint16 referralCode)

Deposits an amount of underlying asset into the reserve, receiving in return overlying bTokens. E.g. User deposits 100 USDC and gets in return 100 bUSDC.

Parameter Name	Type	Description
asset	address	The address of the underlying asset to deposit
amount	uint256	The underlying amount to be deposited, expressed in underlying asset decimals units
onBehalfOf	address	address whom will receive the bTokens. Use msg.sender when the aTokens should be sent to the caller.
referralCode	uint16	referral code for our referral program. Use 0 for no referral.

withdraw

function withdraw( address asset, uint256 amount, address to )

Withdraws an amount of underlying asset from the reserve, burning the equivalent bTokens owned.

Parameter Name	Type	Description
asset	address	The address of the underlying asset to deposit
amount	uint256	The underlying amount to be withdrawn, expressed in underlying asset decimals units
to	address	Address that will receive the underlying, same as msg.sender if the user wants to receive it on his own wallet, or a different address if the beneficiary is a different wallet.

borrow

function borrow( address asset, uint256 amount, address nftAsset, uint256 nftTokenId, address onBehalfOf, uint16 referralCode )

Allows users to borrow a specific amount of the reserve underlying asset. E.g. User borrows 100 USDC, receiving the 100 USDC in his wallet and lock collateral asset in contract.

Parameter Name	Type	Description
asset	address	The address of the underlying asset to borrow
amount	uint256	The underlying amount to be borrowed, expressed in underlying asset decimals units
nftAsset	address	The address of the underlying NFT used as collateral
nftTokenId	uint256	The token ID of the underlying NFT used as collateral
onBehalfOf	address	Address of the user who will receive the loan. Should be the address of the borrower itself calling the function if he wants to borrow against his own collateral
referralCode	uint16	referral code for our referral program. Use 0 for no referral.

repay

function repay( address nftAsset, uint256 nftTokenId, uint256 amount )

Repays a borrowed amount on a specific reserve, burning the equivalent loan owned. E.g. User repays 100 USDC, burning loan and receives collateral asset.

Parameter Name	Type	Description
nftAsset	address	The address of the underlying NFT used as collateral
nftTokenId	uint256	The token ID of the underlying NFT used as collateral
amount	uint256	The underlying amount to be repaid, expressed in underlying asset decimals units.Use type(uint256).max to repay the entire debt, ONLY when the repayment is not executed on behalf of a 3rd party. In case of repayments on behalf of another user, it's recommended to send an amount slightly higher than the current borrowed amount.

Return Values

Parameter Name	Type	Description
repaidAmount	uint256	The underlying payback amount repaid
isBurnLoan	bool	The loan is burned or not, return true if all borrowed debt has been repaid

auction

function auction( address nftAsset, uint256 nftTokenId, uint256 bidPrice, address onBehalfOf )

Function to auction a non-healthy position collateral-wise. The caller (liquidator) want to buy collateral asset of the user getting liquidated. Auction mechanism in Bend is English Auction, the highest bidder will be the winner.

Parameter Name	Type	Description
nftAsset	address	The address of the underlying NFT used as collateral
nftTokenId	uint256	The token ID of the underlying NFT used as collateral
bidPrice	uint256	The bid price of the liquidator want to buy the underlying NFT
onBehalfOf	address	Address of the user who will get the underlying NFT, same as msg.sender if the user wants to receive them on his own wallet, or a different address if the beneficiary of NFT is a different wallet.

redeem

function redeem(address nftAsset, uint256 nftTokenId, uint256 bidFine)

Function to redeem a non-healthy NFT loan which state is in Auction. The caller must be borrower of loan. The borrower can redeem his own things before the redemption time expires.

Parameter Name	Type	Description
nftAsset	address	The address of the underlying NFT used as collateral
nftTokenId	uint256	The token ID of the underlying NFT used as collateral
amount	uint256	The amount to repay the debt
bidFine	uint256	The amount of bid fine

Return Values

Parameter Name	Type	Description
repayAmount	uint256	The underlying payback amount repaid

liquidate

function liquidate( address nftAsset, uint256 nftTokenId, address onBehalfOf )

Function to liquidate a non-healthy NFT loan which state is in Auction. The caller (liquidator) buy collateral asset of the user getting liquidated, and receives the collateral asset.

Parameter Name	Type	Description
nftAsset	address	The address of the underlying NFT used as collateral
nftTokenId	uint256	The token ID of the underlying NFT used as collateral
amount	uint256	The extra amount to repay debt. It should be 0 in most of case.

Return Values

Parameter Name	Type	Description
extraAmount	uint256	The underlying extra amount repaid

View Methods

getReservesList

function getReservesList()

Returns the underlying address list of the initialized reserves.

getReserveData

function getReserveData(address asset)

Returns the state and configuration of the reserve.

Return Values

Parameter Name	Type	Description
configuration	ReserveConfigurationMap	the reserve configuration
liquidityIndex	uint128	the liquidity index. Expressed in ray
variableBorrowIndex	uint128	variable borrow index. Expressed in ray
currentLiquidityRate	uint128	the current supply rate. Expressed in ray
currentVariableBorrowRate	uint128	the current variable borrow rate. Expressed in ray
lastUpdateTimestamp	uint40
bTokenAddress	address	bToken addresses of reserve
debtTokenAddress	address	debtToken addresses of reserve
interestRateAddress	address	address of the interest rate strategy

getReserveConfiguration

function getReserveConfiguration(address asset)

Returns the configuration of the reserve.

getReserveNormalizedIncome

function getReserveNormalizedIncome(address asset)

Returns the normalized income normalized income of the reserve.

getReserveNormalizedVariableDebt

function getReserveNormalizedVariableDebt(address asset)

Returns the normalized variable debt per unit of asset.

getNftsList

function getNftsList()

Returns the underlying address list of the initialized NFTs.

getNftData

function getNftData(address asset)

Returns the state and configuration of the nft.

getNftConfiguration

function getNftConfiguration(address asset)

Returns the configuration of the NFT.

getNftCollateralData

function getNftCollateralData(address nftAsset, uint256 nftTokenId)

Returns the collateral data of the NFT.

Return Values

Parameter Name	Type	Description
totalCollateralInETH	uint256	the total collateral in ETH of the NFT
totalCollateralInReserve	uint256	the total collateral in Reserve of the NFT
availableBorrowsInETH	uint256	the borrowing power left in ETH of the NFT
availableBorrowsInReserve	uint256	the borrowing power left in Reserve of the NFT
ltv	uint256	the loan to value of the user, that is collateral ration
liquidationThreshold	uint256	the liquidation threshold of the NFT
liquidationBonus	uint256	the liquidation bonus of the NFT

getNftDebtData

function getNftDebtData(address nftAsset, uint256 nftTokenId)

Returns the debt data of the NFT.

Return Values

Parameter Name	Type	Description
loanId	uint256	the loan id of the NFT related to
healthFactor	uint256	the current health factor of the NFT
reserveAsset	address	the current borrowed reserve asset of the NFT
totalCollateral	uint256	the total collateral in Reserve of the NFT
totalDebt	uint256	the current borrowed debt of the NFT
availableBorrows	uint256	the borrowing power left of the NFT

getNftAuctionData

function getNftAuctionData(address nftAsset, uint256 nftTokenId)

Returns the auction data of the NFT.

Return Values

Parameter Name	Type	Description
loanId	uint256	the loan id of the NFT
bidderAddres	address	the highest bidder address of the loan
bidPrice	uint256	the highest bid price in Reserve of the loan
bidBorrowAmount	uint256	the borrow amount in Reserve of the loan
bidFine	uint256	the penalty fine of the loan

getNftAuctionEndTime

function getNftAuctionEndTime(address nftAsset, uint256 nftTokenId)

Returns the auction end time of the NFT.

Return Values

Parameter Name	Type	Description
loanId	uint256	the loan id of the NFT
bidStartTimestamp	uint256	the auction start timestamp
bidEndTimestamp	uint256	the aucton end timestamp
redeemEndTimestamp	uint256	the redeem end timestamp

getNftLiquidatePrice

Returns the liquidate price of the NFT which health factor is below 1.

getNftCollateralData

function getNftCollateralData(address nftAsset, address reserveAsset)

Returns the collateral data of the NFT.

Return Values

Parameter Name	Type	Description
totalCollateralInETH	uint256	the total collateral in ETH of the NFT
totalCollateralInReserve	uint256	the total collateral in Reserve of the NFT
availableBorrowsInETH	uint256	the borrowing power in ETH of the NFT
availableBorrowsInReserve	uint256	the borrowing power in Reserve of the NFT
ltv	uint256	the loan to value of the user
liquidationThreshold	uint256	the liquidation threshold of the NFT
liquidationBonus	uint256	the liquidation bonus of the NFT

paused

Returns true if the LendPool is paused