Recipe: Aave lending and borrowing from TypeScript

[PetarStoev02]

Description

Recipe showing how to programmatically interact with Aave (v3) lending protocol from TypeScript — deposit collateral, borrow assets, monitor health factor, and repay loans.

Why this matters

Aave is the largest lending protocol in DeFi ($20B+ TVL). The 32-hour Solidity course teaches this with ethers.js scripts on a forked mainnet — but uses outdated patterns. w3-kit modernizes this with viem and current Aave v3 contracts.

Scope

• Deposit collateral (WETH, USDC, etc.) into Aave
• Read user account data (total collateral, total debt, available borrows, health factor, liquidation threshold)
• Borrow assets against collateral (e.g., borrow DAI against ETH)
• Calculate max safe borrow amount using price feeds
• Repay loans (partial and full)
• Monitor health factor and liquidation risk
• Understand aTokens (interest-bearing receipt tokens)
• Mainnet fork testing pattern

w3-kit approach

• viem for all contract interactions
• Multi-chain: Aave v3 is on Ethereum, Arbitrum, Optimism, Polygon, Base
• Practical examples: deposit-borrow-repay lifecycle, health factor monitoring
• Use w3-kit registry for Aave contract addresses per chain

Acceptance criteria

• Recipe in recipes/evm/
• Full deposit → borrow → repay lifecycle
• Health factor calculation and monitoring
• Multi-chain Aave v3 addresses
• .learn.md explaining how lending pools work (overcollateralization, liquidation, interest rates)

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