Oracles

Oracles makes on-chain and off-chain data available to smart-contracts
The Maker Protocol uses oracles enable the use of price data of various assets to determine a number of important things like when to liquidate a Vault or how much Dai a given Vault can generate.
MakerDAO's oracles receive data from a number of independent feeds that consist of individuals and organizations. Each oracle corresponds to a single asset and its reference price.
Please visit the Oracle Module section for technical Documentation.