Handling Off-chain Data Retrieval

Smart contracts live on the blockchain, isolated from the outside world. But what if your contract needs real-time data, like a cryptocurrency price or a weather report?

This is where oracles come in. In this lesson, we'll learn how to implement patterns for requesting and receiving external data from APIs using Chainlink, ensuring the data is secure and reliable.

Chainlink acts as a bridge, allowing your smart contract to securely interact with off-chain (external) data sources. It works using a request-response cycle:

• Your smart contract sends a request to a Chainlink oracle network.
• A Chainlink node fetches the data from the specified API.
• The Chainlink node then sends a response back to your contract by calling a specific 'callback' function.