DeFi

Decentralized finance, commonly shortened to DeFi, is a set of financial services that runs on public blockchains instead of through banks, brokerages, or other regulated intermediaries. Anyone with an internet connection and a self-custody wallet can lend, borrow, trade, save, and earn yield directly from open protocols, without opening an account or asking permission.

DeFi is built almost entirely on smart contracts, most of them deployed on Ethereum and other programmable blockchain networks. These contracts encode the rules of each service in code: how a loan is collateralized, how a trade is matched, how interest accrues. Once deployed they execute automatically, and balances, fees, and source code remain visible on chain in real time.

The ecosystem now covers most categories that traditional finance offers, plus some that only blockchains make practical:

• Trading. Decentralized exchanges such as Uniswap let users swap tokens directly from their wallet, often using an automated market maker that prices trades against a liquidity pool instead of a traditional order book.
• Lending and borrowing. Money market protocols like Aave accept crypto as collateral and let users borrow other assets against it, with interest rates set algorithmically based on supply and demand.
• Stable value. Stablecoins such as DAI track the price of a fiat currency and serve as the unit of account for most DeFi activity.
• Yield strategies. Through yield farming and liquidity mining, users supply assets to a protocol and earn a share of trading fees, interest, or newly minted reward tokens.
• Derivatives and prediction markets. Specialized protocols offer perpetual futures, options, and on-chain prediction markets that settle without an intermediary.

DeFi removes the traditional gatekeepers between a user and a financial product. There is no minimum balance, no business hours, and no jurisdictional approval before a wallet can interact with a protocol. Total Value Locked (TVL) has become the standard way to track how much capital is committed to these protocols at any given moment, and is widely used to compare ecosystems and individual platforms.

Most DeFi services are operated as decentralized applications, with upgrades and treasury decisions controlled by holders of a governance token such as UNI. Proposals and votes happen directly on chain, which makes parameter changes such as interest rate curves or supported collateral types transparent and auditable.

Because DeFi puts the user in full control, most of the risk falls on them too. Smart contracts can contain bugs that are exploited and drained. Volatile collateral can trigger forced liquidations within minutes. Many protocols depend on price oracles, bridges, or other external systems that introduce their own failure modes. Users are responsible for their own keys, since there is no support desk to reverse a mistaken transaction.

For broader context, the Ethereum blockchain hosts the majority of DeFi activity today, while alternative networks like Solana have grown into significant venues of their own.