Smart contract
Self-executing code deployed on a blockchain that runs deterministically when called, without requiring an intermediary.
Smart contracts are programs stored on-chain that execute when their conditions are triggered. The Ethereum Virtual Machine (EVM) runs Solidity-written contracts; Solana uses Rust-based programs; other chains have their own languages. Once deployed, the contract code is typically immutable — bugs cannot be patched without a coordinated migration.
Smart contracts power DeFi. A Uniswap pool is a smart contract that holds tokens and lets anyone swap them by paying a fee. An Aave lending market is a contract that lets anyone deposit collateral and borrow against it. NFT marketplaces, DAOs, and yield aggregators all run as composable contracts.
Smart contract risk is real. Code exploits have cost users tens of billions of dollars across the industry — re-entrancy bugs, oracle manipulation, flash-loan attacks, governance takeovers. Audits help but don't eliminate risk. Battle-tested contracts (Uniswap, Aave) carry less risk than new launches; novel financial primitives carry the most.
Smart contracts are the computational substrate of DeFi. Understanding what they can and can't do shapes risk assessment for any on-chain position.
How CryptoRadar24 tracks it
CryptoRadar24 references smart-contract activity through DeFi TVL data and reports on major exploits when they affect market structure.
Related terms
FAQ
Are smart contracts actually contracts?
Legally, no — they're executable code, not legal agreements. The "contract" framing reflects deterministic execution, not enforceability in court.
Can a smart contract be hacked?
Yes. Code bugs (re-entrancy, integer overflow, access control) can be exploited. So can the inputs (oracle manipulation, flash-loan attacks). Deployed contracts are usually immutable, so hacks cannot be reverted by the team.
Why are some smart contracts upgradable?
Some teams deploy proxy patterns where the logic contract can be replaced. This trades immutability for the ability to fix bugs — a controversial choice that introduces governance/admin-key risk.
Does Bitcoin have smart contracts?
Limited ones, via Bitcoin Script. Bitcoin's scripting language is intentionally constrained — no loops, no Turing-completeness — to reduce attack surface. Layer-2 solutions like Stacks add richer programmability.