Chainlink is an oracle that provides off-blockchain data to smart contracts.

Chainlink was first described in a white paper published in September, 2017. Chainlink is a decentralized network that connects smart contracts to external data. It aims to bring real world data onto the blockchain so that smart contracts can interact with real world events and information that exist off-blockchain. Chainlink was built to increase the potential applications and possibilities for smart contracts and reduce their need to rely on trusted third parties.