Oracle
A service that provides external data to smart contracts, enabling them to interact with real-world information and data.
Last Updated
2026-03-29
Related Concepts
What is Oracle?
A blockchain oracle is a service that fetches external real-world data and delivers it to smart contracts. Blockchains are isolated by design oracles are the bridge to outside information like asset prices, weather data, or sports results.
How does Oracle work?
- A smart contract requests specific data from an oracle network.
- Off-chain nodes fetch the data from trusted APIs.
- Multiple nodes sign and submit the data on-chain independently.
- The network aggregates responses into a single verified value.
- The smart contract uses this value to execute its logic.
Why does Oracle matter?
Without oracles, smart contracts can only use data already on the blockchain. Oracles enable DeFi lending, derivatives, insurance, and prediction markets.
Key features of Oracle
- Bridges on-chain logic with off-chain data
- Decentralized networks aggregate multiple sources
- Cryptographic proof of data authenticity
- Essential for price feeds in DeFi protocols
Examples of Oracle
Chainlink provides price feeds to thousands of protocols including Aave and Compound. A weather insurance contract uses an oracle to verify rainfall before paying out.
Prediction markets use oracles to confirm election or sports outcomes.