ChainLink is a smart contract platform that allows users to create smart contracts and then connect them to a website application, API, or payment gateway on one end and to a blockchain (such as Bitcoin, Ethereum, or HyperLedger) on the other. In this way, external data can easily be connected to a blockchain and used to run a decentralized application or whatever the user needs (thus creating an Oracle). Banks accounts can be linked so that payments can be sent using both cryptocurrencies and fiat currencies over payment networks. Users can even connect their smart contract to multiple blockchains at once for cross-chain compatibility.
ChainLink (LINK) Ethereum utility tokens can be used to pay ChainLink operators in return for providing their services to smart contracts.