Smart Contracts: The Code That Powers DeFi
Understand how smart contracts work, why they matter for DeFi, and what risks to be aware of.
What Are Smart Contracts?
Smart contracts are self-executing programs stored on a blockchain. They automatically enforce the terms of an agreement when predefined conditions are met, without requiring intermediaries. Once deployed, they cannot be modified — the code is the contract.
How Smart Contracts Enable DeFi
Every DeFi protocol is built on smart contracts. When you swap tokens on Uniswap, lend on Aave, or provide liquidity on Curve, you are interacting with smart contracts that handle the logic, custody, and settlement of your transactions.
Key Properties
- Immutable: Once deployed, the code cannot be changed (though upgradeable patterns exist)
- Transparent: Anyone can read the code and verify its behavior
- Trustless: No counterparty risk — execution is guaranteed by the blockchain
- Composable: Contracts can interact with each other, enabling complex financial products
Smart Contract Risks
- Code bugs: Even audited contracts can have vulnerabilities. Tens of billions have been lost to exploits.
- Upgrade risks: Some contracts have admin keys that could be used maliciously
- Oracle manipulation: Contracts relying on price feeds can be exploited if the oracle is compromised
Best Practices for Users
Always verify you are interacting with the correct contract address. Check audit reports. Start with small amounts. Use established protocols with significant TVL and track records.