Chainlink is a project focused on solving a specific problem: blockchains cannot natively access information from outside their own network, such as real-world stock prices, weather data, or sports scores. Chainlink operates a decentralized network of independent node operators who supply this outside information, commonly called oracle data, to smart contracts that need it.
This matters significantly for DeFi applications, many of which depend on accurate, tamper-resistant price data to function correctly, for example to determine when a loan should be liquidated. Chainlink's network aggregates data from multiple independent sources rather than relying on a single provider, which is intended to reduce the risk of any one source manipulating the data.
The native token, LINK, is used to pay node operators for providing this data and services. Because so much of the DeFi ecosystem relies on accurate external data, Chainlink has become deeply integrated as foundational infrastructure across many blockchain networks.