In plain English
What Smart contract means
A smart contract can hold assets, track balances, or apply rules such as “release tokens only after enough authorized signatures.” Its behavior depends on the code, its inputs, and the blockchain on which it runs. State-changing interactions usually require a transaction and network fee; reading information from a contract may not. Contracts commonly need oracles for external data.
Why it matters
Smart contracts underpin many tokens, decentralized exchanges, lending applications, and wallets. Their automation can reduce reliance on an intermediary for certain functions, but it can also make coding mistakes, malicious permissions, faulty price data, and irreversible transactions consequential. A contract’s name or website does not prove that its code is safe or that a project is legitimate.
Example
A simplified escrow contract holds 1 ETH. Its code releases the ETH to a seller only if two of three named parties approve. If the code instead contains an error that lets one party change the approver list, the blockchain may execute that rule exactly as written. The result depends on the code, not the intended business arrangement.
Quick answers
Common questions
Can a smart contract access a real-world price by itself?+
Not directly in the usual blockchain model. Smart contracts need an external data mechanism, commonly called an oracle, to bring offchain information such as a price or event outcome onto the chain. The oracle then becomes part of the trust and risk model.
Are smart contracts legally binding?+
Not automatically. A smart contract is primarily a technical program. Whether an associated agreement is legally enforceable depends on its terms, the parties, applicable law, jurisdiction, and other facts outside the code itself.
Sources