A smart contract is code deployed on a blockchain that executes automatically when predefined conditions are met. No bank, no lawyer, no escrow agent — just code. Once deployed, a smart contract cannot be stopped, censored, or altered by anyone. This "trustless" execution is the foundation of DeFi, NFTs, prediction markets, and DAOs.
Imagine a vending machine: insert coin, select item, machine dispenses item. No human judgment required — the rules are embedded in the machine. A smart contract is similar: deposit ETH, contract checks the conditions, contract releases funds to the winner. The rules are in the code, not in someone's judgment.
Smart contracts are written in languages like Solidity (for Ethereum) and deployed to the blockchain. Once deployed, they have a permanent address and their code is publicly visible. Every invocation of the contract is a blockchain transaction, creating a permanent, auditable record.
Polymarket's contracts are deployed on Polygon and have been audited by Trail of Bits and other reputable security firms. The resolution oracle system uses multiple data sources to determine event outcomes. Understanding that Polymarket is a smart contract protocol — not a company holding your funds — explains why it can operate with minimal counterparty risk relative to centralised prediction platforms.