Definition: blockchain oracle

A service that queries and transfers off-chain data to smart contracts on a blockchain. Primarily used on the Ethereum network, a blockchain oracle may deliver sensor data, price feeds such as stock market quotes or some outcome (game, election, etc.). It may also provide a bridge between other blockchains as well as a IT systems in an enterprise. A "centralized" oracle queries one source of data and is less reliable than a "decentralized" service that obtains data from multiple sources. See Ethereum and Mina.




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