How does DeFi work?

How DeFi works

DeFi (Decentralized Finance) is the umbrella term for financial services — lending, borrowing, trading, earning yield — that run on blockchains via smart contracts instead of through a bank or broker. A few core ideas:

1. Smart contracts replace intermediaries. A lending protocol like Aave or Compound is just code on Ethereum that holds deposits and pays out loans automatically. No bank manager, no credit check, no paperwork — the rules are public and the same for everyone.

2. You hold your own keys. In centralized finance the bank holds your money. In DeFi your funds sit in your own wallet and interact directly with contracts. The trade-off: if you lose your private keys or send to the wrong address, nobody can reverse it.

3. Key building blocks:

• DEXs (decentralized exchanges) — Uniswap-style AMMs let you swap tokens instantly using liquidity pools instead of a matching engine. Anyone can deposit two tokens into a pool and earn trading fees as a liquidity provider.
• Lending markets — deposit an asset as collateral, borrow against it. Over-collateralization protects the protocol (borrow less than you lock up).
• Stablecoins / yield — lending out assets, staking, or providing liquidity earns interest or fees, which is where "yield farming" and APY figures come from.
• Perpetual/derivatives DEXs — leverage trading without a centralized clearinghouse.
• Oracles — feed real-world prices (Chainlink being the most common) so contracts know the value of collateral.

4. The "composability" idea — DeFi protocols can be stacked like Lego. A stablecoin can be used as collateral in a lending market, which issues an interest-bearing token, which gets listed on a DEX. That's where terms like "DeFi lego" come from.

The main risks are different from a bank: smart-contract bugs (hacks), price volatility of collateral, and the fact that you're fully self-custodied. There's no deposit insurance and no human to call.

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Want me to look at something concrete? I can pull up the top DEXs by real trading volume, show you what's trending today, or browse a sector (DeFi, Lending, Perps) so you can see which protocols actually have usage behind them. Just tell me what you're curious about.