Smart Contract

Self-executing programs stored on a blockchain that automatically carry out predefined terms when specific conditions are met — without requiring intermediaries.

Smart contracts were first proposed by Nick Szabo in 1994 and became practically viable with Ethereum's launch in 2015. A smart contract is a program that runs on a blockchain, automatically executing actions when pre-coded conditions are satisfied. A simple example: "If Alice sends 1 ETH, release token X to Alice's address." The contract executes trustlessly — neither party needs to trust the other because the code enforces the agreement.

Smart contracts are the foundation of most DeFi applications, NFTs, DAOs (decentralized autonomous organizations), and on-chain financial products. A DeFi lending protocol is a smart contract that accepts collateral, automatically issues loans, monitors collateral ratios, and liquidates undercollateralized positions. An NFT is a smart contract that defines ownership and enables transfers. None of these require a central operator — the code is the operator.

Smart contracts have well-known limitations. They cannot access real-world data directly — they require "oracles" (like Chainlink) to bring in external information like prices, weather data, or sports outcomes. They are also permanent: once deployed to the blockchain, the code cannot be changed, so bugs are catastrophic. The 2016 DAO hack exploited a reentrancy bug in a smart contract to drain $60 million worth of ETH, demonstrating how smart contract vulnerabilities can lead to irreversible losses.

This definition is for informational and educational purposes only. Nothing on Finance Compass constitutes financial, investment, or trading advice. Always conduct your own research and consult a qualified professional before making financial decisions.