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Web3 & DApp Development Fundamentals · Lesson

The Oracle Problem

Understand why smart contracts cannot directly access off-chain data and the challenges this presents for DApp functionality.

What is Off-Chain Data?

Welcome! In Web3, DApps often need information that isn't stored directly on the blockchain. This is called off-chain data.

Think of things like current stock prices, real-time weather reports, or the outcome of a sports game. This data exists in the 'real world' outside the blockchain's network.

Blockchains Live in a Bubble

Blockchains are designed to be isolated and self-contained environments. This is crucial for their security and reliability.

Every node in the network must agree on the exact state of the blockchain. If a smart contract could directly fetch external data, different nodes might get different results, breaking consensus.

All lessons in this course

  1. The Oracle Problem
  2. Chainlink Fundamentals
  3. Fetching Off-Chain Data
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