---
title: "Oracle (Blockchain)"
url: "https://www.unknowngravity.com/en/glosario/oraculo-blockchain"
site: Unknown Gravity
published: "2026-09-21T11:55:13+00:00"
modified: "2026-09-21T11:55:14+00:00"
language: en-US
description: "An oracle is the bridge between a blockchain and the real world: smart contracts cannot read a price, an exchange rate or whether a shipment arrived by themselves — someone has to bring them the…"
section: "Home > Oracle (Blockchain)"
---

# Oracle (Blockchain)

GLOSSARY · BLOCKCHAIN & WEB3

What an oracle is in blockchain: how real-world data gets into a smart contract, why oracles are a critical point and what the oracle problem is.

WHAT IS IT? · FOR DUMMIES

An **oracle** is the bridge between a blockchain and the real world: smart contracts cannot read a price, an exchange rate or whether a shipment arrived by themselves — someone has to bring them the data. That someone is the oracle, and everything the contract decides with that data depends on its quality.

WHAT IS IT? · PRO

The "oracle problem" is that a perfect contract with corrupt data perfectly executes the wrong decision: the oracle is the point of trust that the chain cannot verify. That is why serious ones are decentralised networks (Chainlink is the reference) that aggregate multiple sources and nodes with economic incentives, instead of a single API that someone can take down or manipulate.

In tokenized assets, oracles feed valuations, rates and payment events; in DeFi, collateral prices — historically one of the favourite attack vectors, which is why we review them expressly in every [smart contract audit](/en/articulos/smart-contract-audits).

## 01 / Key points

- Brings external data (prices, events) into smart contracts
- The oracle problem: corrupt data = a perfect wrong decision
- Serious ones are decentralised networks with multiple sources (Chainlink)
- Classic DeFi attack vector: audited expressly

## 02 / Advantages

- Enables useful contracts: no real cases without external data
- Decentralised networks reduce the single point of failure
- Signed, auditable data

## 03 / Disadvantages

- An unavoidable point of trust outside the chain
- Manipulable if the source or the aggregation is weak
- Cost and latency for every update

This entry is informative. It is not legal, tax or investment advice. The rules cited change: check the current version on [BOE](https://www.boe.es) and [EUR-Lex](https://eur-lex.europa.eu).