Smart Contract

Think of a smart contract like a vending machine for financial agreements. You put in the inputs, the code checks the conditions, and the outcome executes automatically. No bank, no lawyer, no waiting. Once deployed on the blockchain, the code runs exactly as written—nobody can alter, pause, or censor it on their own.

Ethereum introduced smart contracts in 2015, and they're still the backbone of DeFi. When you swap tokens on Uniswap, take a loan on Aave, or mint an NFT, you're interacting with smart contracts that handle the logic, hold the assets, and enforce the rules behind the scenes.

Smart contracts make complex financial tools possible without traditional intermediaries. Lending protocols automatically liquidate undercollateralized positions. Insurance protocols pay claims based on oracle data. Prediction markets settle based on real-world outcomes. All automatically.

The security model is fundamentally different from regular software. Smart contracts hold real money and are typically immutable (unchangeable) once deployed. A bug can mean permanent loss of funds—as seen in major hacks like The DAO ($60M, 2016) and Wormhole ($320M, 2022). That's why audits, formal verification, and battle-testing with real value are so critical.

For you as a user, every smart contract interaction creates a permanent blockchain transaction. Each swap, stake, approval, or claim is a traceable event that may have tax implications. Knowing which contracts you've interacted with matters for both security (revoking token approvals you no longer need) and tax reporting.