DeFi (Decentralized Finance) is the umbrella term for financial services built on blockchains — most often Ethereum, but also Solana, BSC, Base, and others — that run on smart contracts instead of through banks, brokers, or other centralized intermediaries.
Instead of a bank holding your money and deciding who gets a loan, DeFi apps are open code anyone can inspect and interact with directly. The main categories:
- Lending & borrowing — deposit crypto as collateral, borrow against it (e.g. Aave, Compound). Rates are algorithmically set by supply and demand rather than a bank.
- DEXs (decentralized exchanges) — swap tokens without a middleman using automated market makers (e.g. Uniswap, Raydium). Anyone can provide liquidity and earn fees.
- Perpetual/derivatives DEXs — trade futures-style positions on-chain (e.g. Hyperliquid).
- Yield/Staking — earn interest or rewards by depositing tokens into protocols.
- Stablecoins — assets pegged to a fiat currency (USD mostly) that the rest of DeFi settles in.
- Aggregators — routers that find the best swap price across many DEXs (e.g. Jupiter).
The core ideas that define it:
- Self-custody — you hold your own keys and funds; there's no "the bank has your money" custody model.
- Permissionless — anyone, anywhere, with an internet connection can participate; no account approval or KYC required to use most protocols.
- Transparent — contract code, supply, and reserves are publicly auditable on-chain.
- Composable — apps build on each other ("money legos"), so one protocol's output can feed another's input.
The trade-offs worth knowing:
- Smart-contract risk — a bug or exploit can drain funds with no bank to refund you.
- You are your own security — lose your private key or approve a malicious contract, and your money is gone.
- Volatility & liquidation risk — collateralized loans can be liquidated in sharp price moves.
- Many projects are young — TVL figures can look large but vanish quickly in a downturn or hack.
DeFi is best understood as a parallel financial system — with higher upside access and lower barriers, but also risks that are squarely on the user rather than an institution.
If you'd like to see what's actually live right now, I can pull the top DEXs by 24h volume, the biggest lending protocols by TVL, or what's trending in the sector today — just say the word.