DeFi SuiteLending (Aave v3)

GX Lend

Overview

GX Lend is a decentralized lending and borrowing protocol purpose-built for GX Exchange, deployed on Arbitrum One. Users supply assets to earn yield or borrow against their collateral. All interactions occur through the GX interface at gx.exchange/lend.

How It Works

Supplying Assets

  1. Deposit USDC, ETH, or BTC into GX Lend
  2. Receive interest-bearing gxTokens (e.g., gxUSDC) representing your deposit
  3. gxToken balance increases over time as interest accrues
  4. Withdraw at any time by redeeming gxTokens

Borrowing

  1. Supply collateral (ETH, BTC, or other supported assets)
  2. Borrow up to the asset’s loan-to-value (LTV) ratio
  3. Pay variable or stable interest rates set algorithmically by supply/demand
  4. Repay loan plus interest to unlock collateral

Key Features

FeatureDescription
Variable Interest RatesAlgorithmically determined by utilization ratio
Stable Interest RatesFixed-rate borrowing for predictable costs
Flash LoansBorrow and repay within a single transaction
Health FactorReal-time collateral health monitoring
gxTokensInterest-bearing receipt tokens (ERC-4626 compatible)
Liquidation EngineAutomatic liquidation of undercollateralized positions

Interest Rate Model

Interest rates are determined algorithmically based on the utilization ratio of each asset pool:

  • Low utilization — Low rates to encourage borrowing
  • Optimal utilization (~80%) — Moderate rates balancing supply and demand
  • High utilization (>80%) — Steep rate increase to attract more suppliers

Current APYs

AssetSupply APYBorrow APY
USDC3.2%5.8%
ETH1.8%4.2%
BTC0.9%3.5%

APYs are variable and adjust algorithmically based on pool utilization. The rates above reflect current conditions and will change over time.

Health Factor

Your health factor indicates how safe your borrowed position is relative to your collateral:

Health FactorStatusAction
>= 2.0HealthyNo action needed
>= 1.5GoodPosition is safe but monitor regularly
>= 1.2CautionConsider adding collateral or repaying debt
< 1.2At RiskLiquidation is imminent — add collateral or repay immediately

When the health factor drops below 1.0, the position becomes eligible for liquidation.

Risk Parameters

AssetLTVLiquidation ThresholdLiquidation BonusReserve Factor
USDC80%85%5%10%
ETH80%82.5%5%15%
BTC70%75%10%15%

Smart Contracts

ContractDescription
GXLendPool.solMain lending pool — supply, borrow, repay, withdraw, liquidation
GXOracle.solPrice oracle using Chainlink feeds on Arbitrum
gxUSDC.solInterest-bearing USDC receipt token (ERC-20 + ERC-4626)
GXInterestRate.solAlgorithmic interest rate model based on utilization
GXDataProvider.solFrontend data aggregator for balances, rates, health factors
GXTreasury.solCollects reserve factor revenue for the GX Treasury

Revenue: The Reserve Factor

GX Lend earns revenue through the reserve factor — a percentage of all interest paid that flows to the GX Treasury:

// GXLendPool.sol -- Reserve factor revenue
uint256 public reserveFactor = 1000; // 10% (basis points)
 
function _handleRepayment(address asset, uint256 totalInterest) internal {
    uint256 toTreasury = (totalInterest * reserveFactor) / 10000;
    uint256 toSuppliers = totalInterest - toTreasury;
 
    gxToken.accrueInterest(toSuppliers);
    IERC20(asset).transfer(GX_TREASURY, toTreasury);
}

Revenue at scale:

  • $10M USDC loans at 8% APY = $800,000/year interest
  • 10% reserve factor = $80,000/year to GX Treasury
  • $100M TVL = $800,000/year passive revenue

Liquidation

When a borrower’s health factor drops below 1.0, their position becomes eligible for liquidation:

  1. Liquidators repay a portion of the borrower’s debt
  2. In return, liquidators receive the borrower’s collateral at a discount (liquidation bonus)
  3. The GX Treasury earns a share of the liquidation bonus (5-10%)

Source

All contracts are deployed on Arbitrum One with Chainlink oracle integration.