DeFi 概览

Decentralized Finance (DeFi) recreates financial services — lending, trading, borrowing, earning interest — using smart contracts on a blockchain instead of banks or brokers.

Anyone with a wallet can use these services permissionlessly, with no account approval and no intermediary holding the funds.

Every DeFi protocol is built from smart contracts: self-executing code deployed on-chain. The contract holds the rules and often the funds.

Because the logic is transparent and runs deterministically, users can audit exactly how a protocol behaves before trusting it.

Lending protocols like Aave and Compound let users deposit assets to earn interest, while borrowers take out loans against collateral.

Loans are overcollateralized: you must lock more value than you borrow, protecting lenders from default.

A DEX lets users swap tokens directly from their wallets without a centralized order book or custodian.

Most modern DEXs (Uniswap, Curve) use Automated Market Makers instead of matching buyers and sellers.

Yield is the return earned by putting capital to work. Liquidity providers earn trading fees, lenders earn interest, and stakers earn protocol rewards.

This is the engine that attracts capital into DeFi.

DeFi protocols are composable — one contract can call another freely. A single transaction can borrow, swap, and deposit across several protocols.

This stacking of building blocks is nicknamed money legos.

Stablecoins are tokens pegged to a stable value, usually the US dollar. They are the lifeblood of DeFi, used for trading pairs, loans, and savings.

Examples include USDC, USDT, and DAI (which is crypto-collateralized).

Many DeFi protocols issue governance tokens that let holders vote on parameters like fees and supported assets.

This pushes control toward the community and away from a single company — a step toward true decentralization.

DeFi is powerful but risky:

• Smart contract bugs — code exploits drain funds
• Oracle manipulation — bad price feeds
• Liquidation — collateral sold in a crash
• Impermanent loss — for liquidity providers

Smart contracts cannot read off-chain data on their own. Oracles like Chainlink bring real-world prices on-chain so protocols know an asset is worth.

Reliable oracles are critical — a manipulated price can trigger wrongful liquidations or drain a pool.

DeFi rebuilds finance as open, composable smart contracts: lending markets, DEXs, stablecoins, and yield strategies, all coordinated by governance and fed by oracles.

Next we focus on the core trading engine: Automated Market Makers.

Test your DeFi fundamentals.

You learned that:

• DeFi recreates finance with smart contracts, no intermediaries
• Core pieces: lending, DEXs, stablecoins, yield
• Protocols are composable money legos
• Oracles feed real-world prices on-chain
• Risks include bugs, liquidation, and oracle attacks

Next: how AMMs price trades.