Oracle

Oracle relayer is a service provided by Oracle nodes to bridge different blockchains. Oracle smart contracts are deployed to the target chain and the messages are provided by the Oracle nodes to the smart contract on the target chain and made it available for the other smart contracts. Oracle relayer service is normally governed by trusted Oracle nodes.

Oracle bridges allow data and events from outside sources to trigger crosschain operations like asset transfers. The oracles act as the third-party.

Source: EEA