Blockchain oracles serve as intermediaries that connect smart contracts with external data sources. They facilitate the transfer of data from the outside world into the blockchain ecosystem, which is critical since smart contracts alone cannot access data outside their network. Oracles can be classified into on-chain and off-chain oracles. On-chain oracles verify data on the blockchain, while off-chain oracles collect data from external sources and transmit it to the blockchain. This capability allows smart contracts to react to real-world events, such as financial price feeds, weather data, or event outcomes, thereby broadening their practical applications and functionalities.