aave-integration

Aave V3 Integration Patterns

Core Contracts

Contract	Purpose
Pool	Entry point for supply, borrow, repay, withdraw, flash loans
PoolAddressesProvider	Registry for Pool and related contracts
AToken	Yield-bearing receipt token (rebasing balance)
VariableDebtToken	Tracks variable-rate debt
StableDebtToken	Tracks stable-rate debt (deprecated in most markets)
PriceOracle	Asset price feed aggregator

Supply / Withdraw

import {IPool} from "@aave/v3-core/contracts/interfaces/IPool.sol";

IPool pool = IPool(addressesProvider.getPool());

// Supply: approve first, then supply
IERC20(asset).approve(address(pool), amount);
pool.supply(asset, amount, onBehalfOf, referralCode);

// Withdraw: burns aTokens, returns underlying
pool.withdraw(asset, amount, to);
// Use type(uint256).max to withdraw entire balance

Borrow / Repay

// Borrow: must have sufficient collateral
// interestRateMode: 1 = stable (deprecated), 2 = variable
pool.borrow(asset, amount, 2, referralCode, onBehalfOf);

// Repay: approve first
IERC20(asset).approve(address(pool), amount);
pool.repay(asset, amount, 2, onBehalfOf);
// Use type(uint256).max to repay full debt

Flash Loans (0.05% Fee)

import {IFlashLoanSimpleReceiver} from
    "@aave/v3-core/contracts/flashloan/base/FlashLoanSimpleReceiver.sol";

contract MyFlashLoan is FlashLoanSimpleReceiver {
    constructor(IPoolAddressesProvider provider)
        FlashLoanSimpleReceiver(provider) {}

    function executeOperation(
        address asset,
        uint256 amount,
        uint256 premium,   // 0.05% of amount
        address initiator,
        bytes calldata params
    ) external override returns (bool) {
        require(msg.sender == address(POOL), "unauthorized");
        require(initiator == address(this), "untrusted initiator");

        // Your logic here — you have `amount` of `asset`
        _doArbitrage(asset, amount, params);

        // Repay: amount + premium
        uint256 amountOwed = amount + premium;
        IERC20(asset).approve(address(POOL), amountOwed);
        return true;
    }

    function requestFlashLoan(address asset, uint256 amount) external {
        POOL.flashLoanSimple(address(this), asset, amount, "", 0);
    }
}