Chainlink is a decentralized oracle network that collects data off-chain and delivers it to smart contracts on-chain. It was launched in September 2017 by Sergey Nazarov and Steve Ellis, current CEO and CTO respectively.
Chainlink does not only get data off-chain but also completes some of its computation there. The combination of a real-world data, off-chain computation, and blockchain technology creates a reliable and secure network. Chainlink relies on three types of smart contracts: aggregation contract, which matches data to a relevant smart contract, order-matching contract, that smart contract’s SLA to the best-fitting oracle, and reputation contract, which checks oracle’s reputation. LINK, the native token of the Chainlink network, is a key part of the network’s processes, especially when it comes to smart contracts. The LINK token is utilized for deposits paid by the oracles and is kept by smart contracts if an oracle fails to complete its job. Also, node operators are paid in LINK and one of the ways oracle’s reputation is checked is the number of LINK tokens it is holding.
In August 2021, Chainlink announced the launch of the Cross-Chain Interoperability Protocol (CCIP) that will provide cross-chain communication. CCIP allows its users to enable smart contracts across all public and private blockchain networks.