A blockchain oracle is any device or entity that connects a deterministic blockchain with off-chain data. These oracles enter every data input through an external transaction. This is why oracles are known as blockchain middleware: They are the bridge between the two worlds. Chainlink is a decentralized oracle service, and this Polygon chainlink scaffold dapp will help you understand how to integrate an oracle. It's got everything you need to get started building decentralized applications powered by smart contracts using Chainlink price feeds. Download, build, and explore it's source code.