Chainlink

Chainlink is the dominant oracle network connecting smart contracts to real-world data — prices, weather, sports results, and more. Without oracles, on-chain contracts have no way to know an asset's price or any off-chain fact; Chainlink solves this with a decentralised network of data providers. Its Price Feeds power billions of dollars in DeFi lending and derivatives across dozens of chains. LINK is used to pay oracle node operators and stake in the network's security model.