# Getting started *** {% hint style="info" %} If you are using Windows, we strongly recommend you use Windows Subsystem for Linux (also known as WSL 2). You can use `Hardhat` and `Hardhat ZKsync plugins` without it, but it will work better if you use it.To install Node.js using WSL 2, please read this [guide](https://learn.microsoft.com/en-us/windows/dev-environment/javascript/nodejs-on-wsl). {% endhint %} [Hardhat](https://hardhat.org/) is an Ethereum development environment, designed for easy smart contract development. One of its most prominent features is extendability: you can easily add new plugins to your hardhat project. Along with the official plugins, there are [other plugins from the community](/docs/tooling/hardhat-validium/plugins/hardhat-community-plugins.md) that you can use with Validium. To learn more about Hardhat itself, check out [the official documentation](https://hardhat.org/getting-started/). This tutorial shows you how to setup a Validium Solidity project with Hardhat using the [ZKsync CLI](/docs/cli/getting-started.md). If you are using Vyper, check out the [Vyper plugin documentation](/docs/tooling/hardhat-validium/plugins/hardhat-zksync-vyper.md) or the [vyper-example](https://github.com/matter-labs/hardhat-zksync/tree/main/examples/vyper-example) in GitHub! ### Project setup To create a new project run the `zksync-cli create` command, passing a project name: **Solidity project** ```bash npx zksync-cli create demo --template hardhat_solidity ``` **Vyper project** ```bash npx zksync-cli create demo --template hardhat_vyper ``` This command creates a `demo` folder and clones a Hardhat template project inside it. The downloaded project is already configured and contains all the required plugins. If you want to migrate an existing project, please check the [project migration guide](/docs/tooling/hardhat-validium/guides/migrating-hardhat-project-to-validium.md). ### Hardhat configuration The `hardhat.config.ts` file contains some Validium specific configurations: The Validium deployment and compiler plugin imports: **Solidity project** ```javascript import "@matterlabs/hardhat-zksync"; ``` The `zksolc` block contains the minimal configuration for the compiler. ```javascript zksolc: { version: "latest", // Uses latest available in https://github.com/matter-labs/zksolc-bin settings: {}, }, ``` **Vyper project** ```javascript import "@nomiclabs/hardhat-vyper"; import "@matterlabs/hardhat-zksync-deploy"; import "@matterlabs/hardhat-zksync-vyper"; ``` The `zkvyper` block contains the minimal configuration for the compiler. ```javascript zkvyper: { version: "latest", // Uses latest available in https://github.com/matter-labs/zkvyper-bin settings: {}, }, ``` **Network** The network endpoints of the `zkSyncTestnet` network change dynamically for local tests. ```javascript // dynamically changes endpoints for local tests const zkSyncTestnet = process.env.NODE_ENV == "test" ? { url: "http://localhost:3050", ethNetwork: "http://localhost:8545", zksync: true, } : { url: "https://sepolia.era.zksync.dev", ethNetwork: "sepolia", zksync: true, }; ``` For local Validium testing, modify `url` and `ethNetwork` in `hardhat.config.ts` to align with your local Validium and Ethereum node's L2 and L1 RPC URLs, respectively.This template project includes a basic unit test in the `/test` folder that runs with the local-setup and can be executed with `yarn test`. ### Set your Private Key Rename `.env.example` to `.env` and set your private key: ```bash WALLET_PRIVATE_KEY=YourPrivateKeyHere ``` Your private key will be used for paying the costs of deploying the smart contract. ### Compile and deploy a contract Smart contracts belong in the `contracts` folder. **1. To compile the contract, run** ```bash yarn hardhat compile ``` You'll see the following output: ```bash Compiling 1 Solidity file Successfully compiled 1 Solidity file // Successfully compiled 1 Vyper file - Vyper project ✨ Done in 1.09s. ``` The `artifacts-zk` and `cache-zk` folders appear in the root directory (instead of the regular Hardhat's `artifacts` and `cache`). These folders contain the compilation artifacts (including contract's ABIs) and compiler cache files. The `artifacts-zk` and `cache-zk` folders are included in the `.gitignore` file. The `deploy-greeter.ts` script is in the `deploy` folder. This script uses the `Deployer` class from the `hardhat-zksync-deploy` package to deploy the `Greeter.sol`/`Greeter.vy` contract. ```javascript import { Wallet, utils } from "zksync-ethers"; import * as ethers from "ethers"; import { HardhatRuntimeEnvironment } from "hardhat/types"; import { Deployer } from "@matterlabs/hardhat-zksync-deploy"; // load env file import dotenv from "dotenv"; dotenv.config(); // load wallet private key from env file const PRIVATE_KEY = process.env.WALLET_PRIVATE_KEY || ""; if (!PRIVATE_KEY) throw "⛔️ Private key not detected! Add it to the .env file!"; // An example of a deploy script that will deploy and call a simple contract. export default async function (hre: HardhatRuntimeEnvironment) { console.log(`Running deploy script for the Greeter contract`); // Initialize the wallet. const wallet = new Wallet(PRIVATE_KEY); // Create deployer object and load the artifact of the contract you want to deploy. const deployer = new Deployer(hre, wallet); const artifact = await deployer.loadArtifact("Greeter"); // Estimate contract deployment fee const greeting = "Hi there!"; const deploymentFee = await deployer.estimateDeployFee(artifact, [greeting]); // ⚠️ OPTIONAL: You can skip this block if your account already has funds in L2 // const depositHandle = await deployer.zkWallet.deposit({ // to: deployer.zkWallet.address, // token: utils.ETH_ADDRESS, // amount: deploymentFee.mul(2), // }); // // Wait until the deposit is processed on ZKsync // await depositHandle.wait(); // Deploy this contract. The returned object will be of a `Contract` type, similar to ones in `ethers`. // `greeting` is an argument for contract constructor. const parsedFee = ethers.formatEther(deploymentFee); console.log(`The deployment is estimated to cost ${parsedFee} ETH`); const greeterContract = await deployer.deploy(artifact, [greeting]); // obtain the Constructor Arguments console.log("constructor args:" + greeterContract.interface.encodeDeploy([greeting])); // Show the contract info. const contractAddress = await greeterContract.getAddress(); console.log(`${artifact.contractName} was deployed to ${contractAddress}`); } ``` **2. To execute the deployment script run** ```bash yarn hardhat deploy-zksync --script deploy-greeter.ts ``` This script deploys the `Greeting` contract with the message "Hi there!" to Validium Sepolia Testnet. You should see something like this: ```bash Running deploy script for the Greeter contract The deployment is estimated to cost 0.00579276320831943 ETH constructor args:0x000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000094869207468657265210000000000000000000000000000000000000000000000 Greeter was deployed to 0x46f1d2d8A16DBD8b47e9D61175a826ac667288Be4D1293a22E8 ✨ Done in 12.69s. ``` Congratulations! You have deployed a smart contract project to Validium Sepolia Testnet with Hardhat 🎉 **Request-Rate Exceeded message**: * This message is caused by using the default RPC endpoints provided by ethers. * To avoid this, use your own Sepolia RPC endpoint in the `hardhat.config.ts` file. * Find multiple [node providers here](https://github.com/arddluma/awesome-list-rpc-nodes-providers). ### Interact with the contract The template project contains another script to interact with the contract. 1. Enter the address of the deployed Greeter contract in the `CONTRACT_ADDRESS` variable of the `use-greeter.ts` script:use-greeter.ts ```javascript import { Provider } from "zksync-ethers"; import * as ethers from "ethers"; import { HardhatRuntimeEnvironment } from "hardhat/types"; // load env file import dotenv from "dotenv"; dotenv.config(); // load contract artifact. Make sure to compile first! - Solidity Project import * as ContractArtifact from "../artifacts-zk/contracts/Greeter.sol/Greeter.json"; // load contract artifact. Make sure to compile first! - Vyper Project //import * as ContractArtifact from "../artifacts-zk/contracts/Greeter.vy/Greeter.json"; const PRIVATE_KEY = process.env.WALLET_PRIVATE_KEY || ""; if (!PRIVATE_KEY) throw "⛔️ Private key not detected! Add it to the .env file!"; // Address of the contract on Validium testnet const CONTRACT_ADDRESS = ""; if (!CONTRACT_ADDRESS) throw "⛔️ Contract address not provided"; // An example of a deploy script that will deploy and call a simple contract. export default async function (hre: HardhatRuntimeEnvironment) { console.log(`Running script to interact with contract ${CONTRACT_ADDRESS}`); // Initialize the provider. // @ts-ignore const provider = new Provider(hre.userConfig.networks?.zkSyncTestnet?.url); const signer = new ethers.Wallet(PRIVATE_KEY, provider); // Initialise contract instance const contract = new ethers.Contract(CONTRACT_ADDRESS, ContractArtifact.abi, signer); // Read message from contract console.log(`The message is ${await contract.greet()}`); // send transaction to update the message const newMessage = "Hello people!"; const tx = await contract.setGreeting(newMessage); console.log(`Transaction to change the message is ${tx.hash}`); await tx.wait(); // Read message after transaction console.log(`The message now is ${await contract.greet()}`); } ``` 2. To execute the script, run: ```bash yarn hardhat deploy-zksync --script use-greeter.ts ``` \ The script will: * Retrieve the message from the contract by calling the `greet()` method. * Update the greeting message in the contract with the `setGreeting()` method. * Retrieve the message from the contract again. \ You should see something like this: ```bash Running script to interact with contract Greeter The message is Hello there! Transaction to change the message is 0x12f16578A16DB0f47e9D61175a823ac214288Af The message now is Hello people! ✨ Done in 14.32s. ``` ### Learn more * To learn more about the ZKsync Hardhat plugins check out the [plugins documentation](/docs/tooling/hardhat-validium/guides/getting-started.md). * If you want to know more about how to interact with ZKsync using Javascript, check out the [zksync-ethers Javascript SDK documentation](https://sdk.zksync.io/js/ethers). 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