DeFi Fundamentals & Architecture
Understand the foundations of Decentralized Finance — how it replaces traditional financial intermediaries with smart contracts and creates an open, permissionless financial system.
What is DeFi?
Decentralized Finance (DeFi) is a financial system built on blockchain networks (primarily Ethereum) that replicates and improves upon traditional financial services — lending, borrowing, trading, insurance, and asset management — without centralized intermediaries like banks. Instead of trusting a bank, users trust audited smart contracts that execute automatically. DeFi's Total Value Locked (TVL) peaked at $180B+ and currently holds $50B+. Key properties: Permissionless (anyone with internet can access), Composable (protocols build on each other like Lego blocks — called 'money Legos'), Transparent (all transactions are on-chain and auditable), Non-custodial (users maintain control of their assets), and Programmable (financial products are code, enabling complex automation). The DeFi stack: Layer 1 (Ethereum, Solana), Layer 2 (Arbitrum, Optimism), DEXs (Uniswap, Curve), Lending (Aave, Compound), Derivatives (dYdX, GMX), and Aggregators (1inch, Yearn).
DeFi Building Blocks
- Stablecoins: Dollar-pegged tokens — USDC (centralized, fully backed), DAI (decentralized, over-collateralized), USDT (centralized). The foundation of DeFi liquidity
- Decentralized Exchanges (DEXs): Trade tokens without intermediaries — Uniswap, SushiSwap, Curve. Use Automated Market Makers (AMMs) instead of order books
- Lending & Borrowing: Supply assets to earn interest, borrow assets against collateral — Aave, Compound. Over-collateralized to prevent defaults
- Yield Aggregators: Automatically move funds between protocols to maximize returns — Yearn Finance, Beefy Finance. Handle complex strategies automatically
- Liquid Staking: Stake ETH while maintaining liquidity — Lido (stETH), Rocket Pool (rETH). Earn staking rewards + use staked tokens in DeFi
- Oracles: Bring off-chain data (prices, weather, sports) on-chain — Chainlink is the dominant oracle network with $75B+ secured value
- Bridges: Transfer assets between blockchains — Wormhole, LayerZero, Axelar. Enable cross-chain DeFi but are common attack targets
DeFi Risks & Security
- Smart Contract Risk: Bugs in code can be exploited — $3.8B was stolen from DeFi in 2022 alone. Always check: audits, TVL, time in production
- Impermanent Loss: Providing liquidity to AMMs can lose value relative to simply holding — occurs when token prices diverge from when you deposited
- Oracle Manipulation: Flash loan attacks manipulate price feeds to exploit protocols — multiple DeFi hacks used this vector
- Rug Pulls: Project creators drain liquidity and disappear — common in unaudited, anonymous projects. Red flags: anonymous team, locked liquidity, unrealistic APYs
- Regulatory Risk: Governments increasingly regulating DeFi — SEC enforcement actions, MiCA in Europe, potential KYC requirements
- Liquidation Risk: Borrowed positions can be liquidated if collateral value drops — always maintain healthy collateral ratios (200%+ recommended)