DeFi Protocol
A set of smart contracts on a blockchain that provides an automated financial service such as trading, lending, or yield generation.
What is Protocol?
In the context of decentralized finance, a protocol is a collection of smart contracts deployed on a blockchain that together define the rules and mechanisms for a specific financial service — such as decentralized trading, lending, stablecoin issuance, or yield optimization. Unlike traditional financial software, DeFi protocols are open-source, permissionless, and non-custodial: anyone can interact with them without creating an account, the underlying code is publicly auditable, and the protocol does not hold user funds in a centralized wallet. Protocols are typically governed by a DAO through governance tokens, allowing the community to vote on parameter changes. Well-known DeFi protocols include Uniswap (decentralized exchange), Aave (lending), MakerDAO (stablecoin), Curve (stablecoin trading), and Yearn Finance (yield optimization). The term 'composability' describes how DeFi protocols can be layered — for example, using Curve LP tokens as collateral in Aave.
Example
Aave is a DeFi lending protocol consisting of smart contracts that govern supply and borrow markets, interest rate algorithms, collateral factors, and liquidation mechanisms. A user can supply USDC to Aave's protocol and immediately earn interest from borrowers, with the smart contracts handling all accounting, rate calculations, and collateral checks automatically.
Source: Aave Protocol Documentation