Oracle
A service that brings real-world data onto a blockchain for smart contracts to use.
A blockchain oracle is a service that supplies external, real-world data, such as prices or event outcomes, to smart contracts, which otherwise can't access information outside their own blockchain.
Because smart contracts rely on the data an oracle provides, the reliability and design of an oracle is an important part of evaluating the safety of any application that depends on one. See Kaavon's "Oracle Manipulation" glossary definition for what can go wrong when that reliability assumption fails.
Examples
- A DeFi lending protocol might use a price oracle to determine when a loan should be liquidated.
- Some oracle systems combine data from multiple independent sources to reduce reliance on any single one.
Related research
How Oracle Price Feeds Actually Work, Step by Step
Read the full guide
Pyth Network vs. Chainlink
Read the comparison
What Is a Smart Contract?
Read the full guide
Chainlink
Read the Chainlink research page
Decentralized Oracle Network
Read the Decentralized Oracle Network glossary definition