_You can follow along with the video course from here._ ### Introduction As we delve into smart contract development, **interacting** with external smart contracts will become increasingly frequent. This can involve the use of multiple interfaces, which can clog up the source code and make it difficult to read. ### Interfaces Let's take a look at the `SmartContract` interface as an example: ```solidity interface SmartContract { function someFunction() external view returns(uint, uint){}; } ``` To include this contract, we simply use the `import "./SimpleStorage.sol"` statement at the top of our file. Instead, if the project is not stored locally, we can use imports from Github. ### Direct Imports from GitHub Smart Contracts _hosted on GitHub_ can be imported directly into your project. For instance, consider the `AggregatorV3Interface` contract from Chainlink, which is located in Chainlink's GitHub repository and not in our project's directory. Instead of manually copying all its code into your project and then importing it like this: ```solidity import { AggregatorV3Interface } from "./AggregatorV3Interface.sol"; ``` we can import it more efficiently, as specified in the [Chainlink documentation](https://docs.chain.link/docs/using-chainlink-reference-contracts): ```solidity import { AggregatorV3Interface } from "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol"; ``` This import statement includes the **path** to the AggregatorV3Interface.sol file in the GitHub repository, allowing you to directly import the contract from GitHub or NPM (Node Package Manager). ### Importing from NPM The `@chainlink/contracts` package, available on NPM, follows **Semantic Versioning (SemVer)**, which allows you to download and use specific versions in your contracts (e.g., `npm install @chainlink/contracts@1.2.3`) while being directly _synchronized_ with Chainlink's GitHub repository. The rest of the import path specifies the exact file that Remix should use. Remix interprets `@chainlink/contracts` as a reference to the [NPM package](https://www.npmjs.com/package/@chainlink/contracts), and downloads all the necessary code from it. ```solidity pragma solidity ^0.8.18; import {AggregatorV3Interface} from "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol"; contract FundMe {} ``` ### Conclusion Efficiently managing external smart contracts is crucial in smart contract development to maintain _clean and readable_ source code. Utilizing **direct imports** from GitHub and NPM, as shown with Chainlink's AggregatorV3Interface, simplifies this process. ### 🧑‍💻 Test yourself 1. 📕 What is this statement `@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol` translated into when interpreted by the solidity compiler?