LendingPool

The LendingPool 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. 
The source code can be found on Github here.
If you need development support,  join the #developers channel on the Aave community Discord server.
LendingPool methodsdeposit, borrow, withdraw and repayare only for ERC20, if you want to deposit, borrow, withdraw or repay using native ETH (or native MATIC incase of Polygon), use WETHGateway instead.
Methods
deposit()
function deposit(address asset, uint256 amount, address onBehalfOf, uint16 referralCode)
Deposits a certain amount of an asset into the protocol, minting the same amount of corresponding aTokens, and transferring them to the onBehalfOf address.
For referralCode input explanations, please refer to the referral program section of the documentation. During testing, you can use the referral code: 0.
When depositing, the LendingPool contract must haveallowance()to spend funds on behalf ofmsg.sender for at-leastamount for the asset being deposited. This can be done via the standard ERC20 approve() method.
Parameter Name
Type
Description
asset
address
address of the underlying asset​
amount
uint256
amount deposited, expressed in wei units
onBehalfOf
address
address whom will receive the aTokens. 
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 amount of the underlying asset, i.e. redeems the underlying token and burns the aTokens.
When withdrawing toanother address,msg.sendershould haveaTokenthat will be burned by lendingPool .
Parameter Name
Type
Description
asset
address
address of the underlying asset, not the aToken
amount
uint256
amount deposited, expressed in wei units. 
Use type(uint).max to withdraw the entire balance.
to
address
address that will receive the asset
borrow()
function borrow(address asset, uint256 amount, uint256 interestRateMode, uint16 referralCode, address onBehalfOf)
Borrows amount of asset with interestRateMode, sending the amount to msg.sender, with the debt being incurred by onBehalfOf. 
Note: onBehalfOf must have enough collateral via deposit() or have delegated credit to msg.sender via approveDelegation(). See the Credit Delegation guide for more details.
Parameter Name
Type
Description
asset
address
address of the underlying asset​
amount
uint256
amount to be borrowed, expressed in wei units
interestRateMode
uint256
the type of borrow debt.
Stable: 1, Variable: 2
referralCode
uint16
referral code for our referral program. Use 0 for no referral code.
onBehalfOf
address
address of user who will incur the debt.
Use msg.sender when not calling on behalf of a different user.
repay()
function repay(address asset, uint256 amount, uint256 rateMode, address onBehalfOf)
Repays onBehalfOf's debt amount of asset which has a rateMode.
Parameter Name
Type
Description
asset
address
address of the underlying asset​
amount
uint256
amount to be borrowed, expressed in wei units.
Use uint(-1) 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.
rateMode
uint256
the type of borrow debt.
Stable: 1, Variable: 2
onBehalfOf
address
address of user who will incur the debt.
Use msg.sender when not calling on behalf of a different user.
swapBorrowRateMode()
function swapBorrowRateMode(address asset, uint256 rateMode)
Swaps the msg.sender's borrow rate modes between stable and variable.
Parameter Name
Type
Description
asset
address
address of the underlying asset​
rateMode
uint256
the rate mode the user is swapping from.
Stable: 1, Variable: 2
setUserUseReserveAsCollateral()
function setUserUseReserveAsCollateral(address asset, bool useAsCollateral)
Sets the asset of msg.sender to be used as collateral or not.
Parameter Name
Type
Description
asset
address
address of the underlying asset​
useAsCollateral
bool
true if the asset should be used as collateral
liquidationCall()
function liquidationCall(address collateral, address debt, address user, uint256 debtToCover, bool receiveAToken)
Liquidate positions with a health factor below 1. Also see our Liquidations guide.
When the health factor of a position is below 1, liquidators repay part or all of the outstanding borrowed amount on behalf of the borrower, while receiving a discounted amount of collateral in return (also known as a liquidation 'bonus"). Liquidators can decide if they want to receive an equivalent amount of collateral aTokens, or the underlying asset directly. When the liquidation is completed successfully, the health factor of the position is increased, bringing the health factor above 1.
Liquidators can only close a certain amount of collateral defined by a close factor. Currently the close factor is 0.5. In other words, liquidators can only liquidate a maximum of 50% of the amount pending to be repaid in a position. The liquidation discount applies to this amount.
Liquidators must approve() the LendingPool contract to use debtToCover of the underlying ERC20 of theasset used for the liquidation.
NOTES
In most scenarios, profitable liquidators will choose to liquidate as much as they can (50% of the user position).
debtToCover parameter can be set to uint(-1) and the protocol will proceed with the highest possible liquidation allowed by the close factor.
To check a user's health factor, use getUserAccountData().
Parameter Name
Type
Description
collateral
address
address of the collateral reserve
debt
address
address of the debt reserve
user
address
address of the borrower
debtToCover
uint256
amount of asset debt that the liquidator will repay
receiveAToken
bool
if true, the user receives the aTokens equivalent of the purchased collateral. If false, the user receives the underlying asset directly.
flashLoan()
function flashLoan(address receiverAddress, address[] calldata assets, uint256[] calldata amounts, uint256[] modes, address onBehalfOf, bytes calldata params, uint16 referralCode)
Sends the requested amounts of assets to the receiverAddress contract, passing the included params. 
If the flash loaned amounts + fee is not returned by the end of the transaction, then the transaction will either:
revert if the associated mode is 0,
onBehalfOf incurs a stable debt if mode is 1, or
onBehalfOf incurs a variable debt if mode is 2.
Your contract which receives the flash loaned amounts must conform to the IFlashLoanReceiver interface. For more, see the flash loan guides.
Parameter Name
Type
Description
receiverAddress
address
address of the contract receiving the funds.
Must implement the IFlashLoanReceiver interface.
assets
address[]
addresses of the reserves to flashloan
amounts
uint256[]
amounts of assets to flashloan.
This needs to contain the same number of elements as assets.
modes
uint256[]
the types of debt to open if the flashloan is not returned.
0: Don't open any debt, just revert
1: stable mode debt
2: variable mode debt
onBehalfOf
address
if the associated mode is not0 then the incurred debt will be applied to the onBehalfOf address.
Note: onBehalfOf must already have approved sufficient borrow allowance of the associated asset to msg.sender
params
bytes
bytes-encoded parameters to be used by the receiverAddress contract
referralCode
uint16
referral code for our referral program​
View Methods
getReserveData()
function getReserveData(address asset)
Returns the state and configuration of the reserve
Parameter Name
Type
Description
asset
address
address of the reserve
Return values
Parameter Name
Type
Description
configuration
uint256
See the whitepaper for details on why a bitmask was used.
To find out more about these values, see the Risk docs.
bit 0-15: LTV
bit 16-31: Liq. threshold
bit 32-47: Liq. bonus
bit 48-55: Decimals
bit 56: reserve is active
bit 57: reserve is frozen
bit 58: borrowing is enabled
bit 59: stable rate borrowing enabled
bit 60-63: reserved
bit 64-79: reserve factor
liquidityIndex
uint128
liquidity index in ray
variableBorrowIndex
uint128
variable borrow index in ray
currentLiquidityRate
uint128
current supply / liquidity / deposit rate in ray
currentVariableBorrowRate
uint128
current variable borrow rate in ray
currentStableBorrowRate
uint128
current stable borrow rate in ray
lastUpdateTimestamp
uint40
timestamp of when reserve data was last updated
aTokenAddress
address
address of associated aToken (tokenised deposit)
stableDebtTokenAddress
address
address of associated stable debt token
variableDebtTokenAddress
address
address of associated variable debt token
interestRateStrategyAddress
address
address of interest rate strategy. 
See Risk docs for more info.
id
uint8
the position in the list of active reserves
getUserAccountData()
function getUserAccountData(address user)
Returns the user account data across all the reserves
Parameter Name
Type
Description
user
address
address of the user
Return values
Parameter Name
Type
Description
totalCollateralETH
uint256
total collateral in ETH of the user
totalDebtETH
uint256
total debt in ETH of the user
availableBorrowsETH
uint256
borrowing power left of the user
currentLiquidationThreshold
uint256
liquidation threshold of the user
ltv
uint256
Loan To Value of the user
healthFactor
uint256
current health factor of the user.
Also see liquidationCall()​
getConfiguration()
function getConfiguration(address asset)
Returns the configuration of the reserve
Parameter Name
Type
Description
asset
address
address of the reserve
Return values
Return Type
Description
uint256
See the whitepaper for details on why a bitmask was used.
bit 0-15: LTV
bit 16-31: Liq. threshold
bit 32-47: Liq. bonus
bit 48-55: Decimals
bit 56: reserve is active
bit 57: reserve is frozen
bit 58: borrowing is enabled
bit 59: stable rate borrowing enabled
bit 60-63: reserved
bit 64-79: reserve factor
getUserConfiguration()
function getUserConfiguration(address user)
Returns the configuration of the user across all the reserves.
Parameter Name
Type
Description
user
address
address of the user
Return values
Return Type
Description
uint256
See the whitepaper for details on why a bitmask was used.
The bitmask is divided into pairs of bits, one pair for each asset. 
​
The first bit of the pair indicates if it is being used as collateral by the user, the second bit indicates if it is being borrowed.

The corresponding assets are in the same position as getReservesList()

For example, if the hex value returned is 0x40020,  which represents a decimal value of 262176, then in binary it is 1000000000000100000. If we format the binary value into pairs, starting from the right, we get 1 00 00 00 00 00 00 10 00 00.
If we start from the right and move left in the above binary pairs, the third pair is 10. The third reserve listed in getReserveList() is WETH. Therefore the 1 indicates that WETH is used as collateral, and 0 indicates that WETH has not been borrowed by this user. 
If we continue to go to the end of the binary pairs (furthest left), we have 1 which can also be represented as 01. This is the 10th pair, which in getReserveList() is DAI. Therefore the 0 indicates that DAI is not used as collateral, and the 1 indicates that it is being borrowed by this user.
In short, if a user is using WETH as collateral and has borrowed DAI, then the value returned would be 0x40020 (in hex) or 262176 (in decimal).
getReserveNormalizedIncome()
function getReserveNormalizedIncome(address asset)
Returns the normalized income per unit of asset. 
A return value of 1e271e271e27 indicates no income. As time passes, the income is accrued. A value of 2∗1e272 * 1e272∗1e27 indicates that for each unit of asset, two units of income have been accrued.
Parameter Name
Type
Description
asset
address
address of the reserve
getReserveNormalizedVariableDebt()
function getReserveNormalizedVariableDebt(address asset)
Returns the normalized variable debt per unit of asset.
A return value of 1e271e271e27 indicates no debt. As time passes, the debt is accrued. A value of 2∗1e272 * 1e272∗1e27 indicates that for each unit of asset, two units of debt have been accrued.
Parameter Name
Type
Description
asset
address
address of the reserve
paused()
function paused()
Returns true if the LendingPool is paused.
getReservesList()
function getReservesList()
Returns the list of initialized reserves.
getAddressesProvider()
function getAddressesProvider()
Returns the addresses provider.
Error Codes
In order to reduce gas usage and code size, aave contracts return numbered errors. If you are making calls to the protocol and receive numbered errors, you can use our error code reference guide to know what the error number means. Alternatively, you can also find what the numbers represent by checking the Errors.sol​
The Core Protocol - Previous
Protocol Overview
ILendingPool
Last updated 3 weeks ago
Parameter Name	Type	Description
`receiverAddress`	address	address of the contract receiving the funds. Must implement the `IFlashLoanReceiver` interface.
`assets`	`address[]`	addresses of the reserves to flashloan
`amounts`	`uint256[]`	amounts of `assets` to flashloan. This needs to contain the same number of elements as `assets`.
`modes`	`uint256[]`	the types of debt to open if the flashloan is not returned. 0: Don't open any debt, just revert 1: stable mode debt 2: variable mode debt
`onBehalfOf`	address	if the associated `mode` is not`0` then the incurred debt will be applied to the `onBehalfOf` address. Note: `onBehalfOf` must already have approved sufficient borrow allowance of the associated asset to `msg.sender`
`params`	bytes	bytes-encoded parameters to be used by the `receiverAddress` contract
`referralCode`	uint16	referral code for our referral program