Oracle: what it means in crypto

Oracle

A system that brings outside information, such as prices, onto a blockchain for smart contracts to use.

Oracle in more detail

A contract cannot see the outside world. To know that ETH is worth $4,000, a lending service relies on an oracle, a system that brings prices onto the blockchain.

If the oracle can be fooled, so can the service. In October 2022 a trader bought large amounts of one token on the three exchanges that fed the price oracle of a service called Mango Markets. The oracle price rose more than 13-fold in about 30 minutes. He then borrowed against his inflated holdings and withdrew over $110 million. The US Commodity Futures Trading Commission called it oracle manipulation. He later returned about $67 million.

FROM LESSON 45 · 5 MIN READThe risks of DeFiDeFi fails in a handful of known ways. Learn how contract bugs, manipulated price feeds, admin keys, depegs and fake websites cost users money, and the habits that limit your exposure.Read the lesson

All 128 terms · Checked against the lesson's sources on 10 October 2026.

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