Lending Pool

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 here.

Web3 code samples exclude the imports and transaction related parts to focus on methods interactions.

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

Methods

deposit()

function deposit( address _reserve, uint256 _amount, uint16 _referralCode)

Deposits a certain _amount of an asset specified by the _reserve parameter.

The caller receives a certain amount of corresponding aTokens in exchange. aTokens are 1:1 redeemable for the underlying token. For more info, see the aTokens section.

For _referralCode input explanations, please refer to the referral program section of this documentation. During testing, you can use the referral code: 0.

When depositing an ERC-20 token, the LendingPoolCore contract (which is different from the LendingPool contract) will need to have the relevant allowance via approve() of _amount for the underlying ERC20 of the _reserve asset you are depositing.

ETH deposits

Our protocol doesn't use any EIP-20 wrapper such as wETH for ETH deposits, therefore amount parameter of deposit() method must match the msg.value parameter of the transaction, and be included in your deposit() call.

E.g: lendingPool.deposit{ value: msg.value }(reserve, msg.value, referralCode)

Since ETH is used directly in the protocol (instead of an abstraction such as WETH), we use a mock address to indicate ETH: 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE

ERC20 deposits

The _reserve parameter corresponds to the ERC20 contract address of the underlying asset.

// Import interface for ERC20 standard
import "openzeppelin-solidity/contracts/token/ERC20/IERC20.sol";

// ... rest of your contract ...

// Retrieve LendingPool address
LendingPoolAddressesProvider provider = LendingPoolAddressesProvider(address(0x24a42fD28C976A61Df5D00D0599C34c4f90748c8)); // mainnet address, for other addresses: https://docs.aave.com/developers/developing-on-aave/deployed-contract-instances
LendingPool lendingPool = LendingPool(provider.getLendingPool());

// Input variables
address daiAddress = address(0x6B175474E89094C44Da98b954EedeAC495271d0F); // mainnet DAI
uint256 amount = 1000 * 1e18;
uint16 referral = 0;

// Approve LendingPool contract to move your DAI
IERC20(daiAddress).approve(provider.getLendingPoolCore(), amount);

// Deposit 1000 DAI
lendingPool.deposit(daiAddress, amount, referral);

setUserUseReserveAsCollateral()

function setUserUseReserveAsCollateral(address _reserve, bool _useAsCollateral)

Enable the user's specific deposit to be used as collateral. Users will only be able to disable deposits that are not currently being used as collateral.

/// Retrieve LendingPoolAddress
LendingPoolAddressesProvider provider = LendingPoolAddressesProvider(address(0x24a42fD28C976A61Df5D00D0599C34c4f90748c8)); // mainnet address, for other addresses: https://docs.aave.com/developers/developing-on-aave/deployed-contract-instances
LendingPool lendingPool = LendingPool(provider.getLendingPool());

/// Input variables
address daiAddress = address(0x6B175474E89094C44Da98b954EedeAC495271d0F); // mainnet DAI
bool useAsCollateral = true;

/// setUserUseReserveAsCollateral method call
lendingPool.setUserUseReserveAsCollateral(daiAddress, useAsCollateral);

borrow()

function borrow(address _reserve, uint256 _amount, uint256 _interestRateMode, uint16 _referralCode)

Transfers a specific amount of the asset identified by the _reserve parameter to the msg.sender, provided that the caller has preemptively deposited enough collateral to cover the borrow.

Every borrow can be opened with a stable or variable rate mode. Borrows have infinite duration and there is no repayment schedule. In case of price fluctuations, a borrow position is liquidated if the price of the collateral drops below a certain threshold. Please refer to the White Paper to understand how the stable rate economy works.

For _referralCode input explanations, please refer to the referral program section of this documentation. During testing, you can use the referral code: 0.

In our documentation and elsewhere, we refer to stable rates instead of the deprecated fixed rates. However in the audited smart contract code, the term fixed rate remains in use.

/// Retrieve LendingPool address
LendingPoolAddressesProvider provider = LendingPoolAddressesProvider(address(0x24a42fD28C976A61Df5D00D0599C34c4f90748c8)); // mainnet address, for other addresses: https://docs.aave.com/developers/developing-on-aave/deployed-contract-instances
LendingPool lendingPool = LendingPool(provider.getLendingPool());

/// Input variables
address daiAddress = address(0x6B175474E89094C44Da98b954EedeAC495271d0F); // mainnet DAI
uint256 amount = 1000 * 1e18;

/// 1 is stable rate, 2 is variable rate
uint256 variableRate = 2;
uint256 referral = 0;

/// Borrow method call
lendingPool.borrow(daiAddress, amount, variableRate, referral);

repay()

function repay( address _reserve, uint256 _amount, address payable _onBehalfOf)

Repay a borrowed asset, either fully or partially. The _onBehalfOf parameter can be used to repay the debt of a different user.

When a third-party is repaying another user debt on their behalf, the third-party address needs to approve() the LendingPoolCore contract (which is different from the LendingPool contract) with _amount of the underlying ERC20 of the _reserve contract.

// Import interface for ERC20 standard (only needed if repaying onBehalfOf)
import "openzeppelin-solidity/contracts/token/ERC20/IERC20.sol";

/// Retrieve LendingPool address
LendingPoolAddressesProvider provider = LendingPoolAddressesProvider(address(0x24a42fD28C976A61Df5D00D0599C34c4f90748c8)); // mainnet address, for other addresses: https://docs.aave.com/developers/developing-on-aave/deployed-contract-instances
LendingPool lendingPool = LendingPool(provider.getLendingPool());

/// Input variables
address daiAddress = address(0x6B175474E89094C44Da98b954EedeAC495271d0F); // mainnet DAI
uint256 amount = 1000 * 1e18;

/// If repaying own loan
lendingPool.repay(daiAddress, amount, msg.sender);

/// If repaying on behalf of someone else
address userAddress = /*users_address*/;
IERC20(daiAddress).approve(provider.getLendingPoolCore(), amount); // Approve LendingPool contract
lendingPool.repay(daiAddres, amount, userAddress);

swapBorrowRateMode()

function swapBorrowRateMode(address _reserve)

Swaps the msg.sender's borrow rate modes between stable and variable.

/// Retrieve the LendingPool address
LendingPoolAddressesProvider provider = LendingPoolAddressesProvider(address(0x24a42fD28C976A61Df5D00D0599C34c4f90748c8)); // mainnet address, for other addresses: https://docs.aave.com/developers/developing-on-aave/deployed-contract-instances
LendingPool lendingPool = LendingPool(provider.getLendingPool());

/// Input variables
address daiAddress = address(0x6B175474E89094C44Da98b954EedeAC495271d0F); // mainnet DAI

/// swapBorrowRateMode method call
lendingPool.swapBorrowRateMode(daiAddress);

rebalanceStableBorrowRate()

function rebalanceStableBorrowRate(address _reserve, address _user)

Rebalances the stable rate of _user. If the user is not borrowing at a stable rate or the conditions for the rebalance are not satisfied, the transaction gets reverted.

Please refer to the White Paper for details on how and when a user position can be rebalanced.

/// Retrieve the LendingPool address
LendingPoolAddressesProvider provider = LendingPoolAddressesProvider(address(0x24a42fD28C976A61Df5D00D0599C34c4f90748c8)); // mainnet address, for other addresses: https://docs.aave.com/developers/developing-on-aave/deployed-contract-instances
LendingPool lendingPool = LendingPool(provider.getLendingPool());

/// Input variables
address daiAddress = address(0x6B175474E89094C44Da98b954EedeAC495271d0F); // mainnet DAI
address rebalancedUser = /*address_to_rebalance*/;

/// rebalanceStableBorrowRate method call
lendingPool.rebalanceStableBorrowRate(daiAddress, rebalancedUser);

liquidationCall()

function liquidationCall(address _collateral, address _reserve, address _user, uint256 _purchaseAmount, 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 discount for liquidating is in terms of this amount.

Liquidators must approve() the LendingPoolCore contract (which is different from the LendingPool contract) to use _purchaseAmount of the underlying ERC20 of the _reserve asset used for the liquidation.

NOTES

  • In most scenarios, profitable liquidators will choose to liquidate as much as they can (50% of the _user position).

  • _purchaseAmount parameter can be set to uint(-1) and the protocol will proceed with the highest possible liquidation allowed by the close factor.

  • For ETH liquidations, msg.value of the transaction should be equal to the _purchaseAmount parameter.

  • To check a user's health factor, use getUserAccountData().

/// Import interface for ERC20 standard
import "openzeppelin-solidity/contracts/token/ERC20/IERC20.sol";

/// Retrieve the LendingPool address
LendingPoolAddressesProvider provider = LendingPoolAddressesProvider(address(0x24a42fD28C976A61Df5D00D0599C34c4f90748c8)); // mainnet address, for other addresses: https://docs.aave.com/developers/developing-on-aave/deployed-contract-instances
LendingPool lendingPool = LendingPool(provider.getLendingPool());

/// Input variables
address collateralAddress = /*collateral_address*/;
address daiAddress = address(0x6B175474E89094C44Da98b954EedeAC495271d0F); // mainnet DAI
address userAddress = /*user_address_being_liquidated*/;
uint256 purchaseAmount = 100 * 1e18;
bool receiveATokens = true;

/// Approve LendingPool contract to move your DAI
IERC20(daiAddress).approve(provider.getLendingPoolCore(), purchaseAmount);

/// LiquidationCall method call
lendingPool.liquidationCall(
    collateralAddress,
    daiAddress,
    userAddress,
    purchaseAmount,
    receiveATokens
);

flashLoan()

function flashLoan(address payable _receiver, address _reserve, uint _amount, bytes memory _params) external

Allows the calling contract to borrow (without collateral) from the _reserve pool, a certain _amount of liquidity, that must be returned before the end of the transaction.

Since the Flash Loan occurs within 1 transaction, it is only possible to call this function successfully on the smart contract level (i.e. Solidity or Vyper).

Need help implementing a Flash Loan? See the Flash Loan tutorial and/or join the #development channel on our discord.

Flash Loans incur a fee of 0.09% of the loan amount.

/**
* Flash Loan of 1000 DAI.
* See the full tutorial here: https://docs.aave.com/developers/tutorials/performing-a-flash-loan
*/

/// Retrieve the LendingPool address
LendingPoolAddressesProvider provider = LendingPoolAddressesProvider(address(0x24a42fD28C976A61Df5D00D0599C34c4f90748c8)); // mainnet address, for other addresses: https://docs.aave.com/developers/developing-on-aave/deployed-contract-instances
LendingPool lendingPool = LendingPool(provider.getLendingPool());

/// Input variables

/* the receiver is a contract that implements the IFLashLoanReceiver interface */
address receiver = /*contract_address*/;
address daiAddress = address(0x6B175474E89094C44Da98b954EedeAC495271d0F); // mainnet DAI
uint256 amount = 1000 * 1e18;

// If no params are needed, use an empty params:
bytes memory params = "";
// Else encode the params like below (bytes encoded param of type `address` and `uint`)
// bytes memory params = abi.encode(address(this), 1234);

/// flashLoan method call
lendingPool.flashLoan(receiver, daiAddress, amount, params);

View Methods

getReserveConfigurationData()

function getReserveConfigurationData(address _reserve)

Returns specific reserve's configuration parameters.

getReserveData()

function getReserveData(address _reserve)

Returns global information on any asset reserve pool

getUserAccountData()

function getUserAccountData(address _user)

Returns information of a reserve exclusively related with a particular user address

getUserReserveData()

function getUserReserveData(address _reserve, address _user)

Returns information related to the user data on a specific reserve

getReserves()

function getReserves()

Returns an array of all the active reserves addresses.

Emitted Events

The LendingPool contract produces events that can be monitored on the Ethereum blockchain. For more information on emitted events and filters, refer to the official solidity documentation.

If you are analysing data about Aave Protocol, see the GraphQL or Blockchain data section.

In Aave protocol, reserve is defined by the smart-contract of the asset used for the method interaction.

  • A list of all smart-contract addresses is available in here.

  • To avoid the usage of an ETH wrapper throughout the protocol (such as WETH), a mock address is used for the ETH reserve: 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE

Deposit

RedeemUnderlying

Borrow

Repay

Swap

ReserveUsedAsCollateralEnabled

ReserveUsedAsCollateralDisabled

RebalanceStableBorrowRate

FlashLoan

OriginationFeeLiquidated

LiquidationCall

Last updated