# Quickstart

VIA Network is a fork of ZKsync Era, inheriting its core technology and developer tooling. This means all ZKsync-compatible tools work seamlessly on VIA with minimal configuration changes. This documentation mirrors ZKsync's Hardhat setup but tailored for VIA Network.

### **Prerequisites**

Before proceeding, ensure you have the following installed:

* [Node.js](https://nodejs.org/) (v18+ recommended),
* [Yarn](https://yarnpkg.com/) or npm,
* A wallet with testnet tokens (for gas fees), you can bridge BTC to Via Network chain using the [bridge UI](https://docs.vianetwork.xyz/user-guide/bridge-btc-between-bitcoin-and-via),
* Basic knowledge of Solidity and Hardhat.

### **Setting Up the Example Project**

Clone the `via-playground` project and install dependencies:

```sh
git clone https://github.com/vianetwork/via-core.git
cd via-core/via-playground
yarn install
```

### **Configuring Hardhat for** Via Network

The `hardhat.config.ts` file contains the network configuration. Ensure it includes the Via Network **RPC endpoint** and your wallet's private key (for deployment).

```typescript
module.exports = {
  defaultNetwork: 'via-testnet',
  solidity: "0.8.27",
  networks: {
    via-testnet: {
      url: "https://via.testnet.viablockchain.dev" // VIA testnet RPC endpoint
      chainId: 25223, // Via testnet chainId
      accounts: [process.env.PRIVATE_KEY],
    },
  },
};
```

> **Note**: Store private keys in `.env` (use `dotenv` package for security).

### **Writing & Compiling the Smart Contract**

The `contracts/` directory contains example contracts (e.g., **`CrowdfundingCampaign.sol`**).

```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract CrowdfundingCampaign {
    address public owner;
    uint256 private fundingGoal;
    uint256 private totalFundsRaised;
    mapping(address => uint256) private contributions;

    event ContributionReceived(address contributor, uint256 amount);
    event GoalReached(uint256 totalFundsRaised);

    constructor(uint256 _fundingGoal) {
        owner = msg.sender;
        fundingGoal = _fundingGoal;
    }

    function contribute() public payable {
        require(msg.value > 0, "Contribution must be greater than 0");
        contributions[msg.sender] += msg.value;
        totalFundsRaised += msg.value;

        emit ContributionReceived(msg.sender, msg.value);

        if (totalFundsRaised >= fundingGoal) {
            emit GoalReached(totalFundsRaised);
        }
    }

    function withdrawFunds() public {
        require(msg.sender == owner, "Only the owner can withdraw funds");
        require(totalFundsRaised >= fundingGoal, "Funding goal not reached");

        uint256 amount = address(this).balance;
        totalFundsRaised = 0;

        (bool success, ) = payable(owner).call{value: amount}("");
        require(success, "Transfer failed.");
    }

    function getTotalFundsRaised() public view returns (uint256) {
        return totalFundsRaised;
    }

    function getFundingGoal() public view returns (uint256) {
        return fundingGoal;
    }
}
```

Compile the contract

```sh
npx hardhat compile
```

### **Deploying the Contract to** Via Network

Deploy the **CrowdfundingCampaign** using the following command:

```sh
npx hardhat deploy --amount 100
```

The `amount` flag is the initial amount deposited in the campaign.

> **Expected Output**:\
> CrowdfundingCampaign`deployed to: 0x123...abc`

### Interact with the CrowdfundingCampaign contract

Let's now create some transactions to interact with the deployed contract

```
# Contribute to the Campaign
npx hardhat contribute --amount 10

# Get crowdfunding stats
npx hardhat stats

# The user withdraws funds from the crowdfunding
npx hardhat withdraw
```

**Happy Building on** Vianetwork**!** 🚀