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What is an oracle?

Why smart contracts need someone to tell them what happened, and why that someone matters.

Real-world answers

Smart contracts can’t see the world. Whoever tells them what happened controls the money.

An open process

With Augur, no party controls the answer. Any app can ask a question. Anyone can report an answer or challenge one. No approval needed; fees and bonds apply.

Terms in this guide

All key terms →
Oracle
A service that tells a blockchain what happened in the real world.