# What is Chainlink ? ChainLink is the leading decentralised [oracle](https://hackmd.io/@HHK-ETH/what-is-an-oracle) solution. It bridges off-chain data to on-chain data. It is used whenever a smart contract need accurate real world data to work, can be prices, weather, sport results... For example : [ChainLink price feeds](https://data.chain.link/ethereum/mainnet/crypto-usd) are used by many DeFi app that need aggregated price of a token. You can learn more about ChainLink on their [official website](https://chain.link/).