What is Chainlink?
Chainlink (LINK) is the largest decentralized oracle network in crypto. Launched in 2017 by SmartContract.com (now Chainlink Labs), it connects smart contracts with real-world data - prices, weather, sports outcomes, proofs of reserve - by aggregating signed responses from a network of independent node operators.
Chainlink's price feeds are the dominant pricing layer in DeFi. Virtually every major lending protocol, stablecoin and derivatives market on Ethereum uses Chainlink feeds to value collateral, trigger liquidations, or settle contracts. The network extends to other chains via its Cross-Chain Interoperability Protocol (CCIP).
How does Chainlink work?
Chainlink nodes retrieve data from APIs and on-chain sources, sign their responses, and post them to on-chain aggregator contracts. Each feed is composed of many independent nodes, and the aggregator takes the median of their reports. This makes manipulation expensive - an attacker would need to compromise or bribe a majority of the node set for a given feed.
LINK is used as the payment asset for oracle services and as the staking collateral under Chainlink's Economic Security program. Staked LINK can be slashed for deliberate misreporting, giving users a financial guarantee on top of the reputation-based security that already underwrites the feeds.