Deploying a Counter Contract with Foundry

This guide will walk you through deploying a counter contract using Foundry, a fast and portable toolkit for Ethereum application development.

1. Prerequisites

Before you begin, make sure you have:

• A code editor (e.g., VS Code)
• Git installed
• (Optional) MetaMask wallet for deploying to testnets
• (Optional) RPC endpoint for deploying to a network

2. Install Foundry

Open your terminal and run:

curl -L https://foundry.paradigm.xyz | bash

This installs foundryup, the Foundry installer.

Next, run:

foundryup

This will install the Foundry toolchain (forge, cast, anvil, chisel).

Check the installation:

forge --version

3. Initialize a New Project

Create a new directory for your project and initialize Foundry:

forge init Counter
cd Counter

This creates a project with the following structure:

• src/ - for your smart contracts
• test/ - for Solidity tests
• script/ - for deployment scripts
• lib/ - for dependencies
• foundry.toml - project configuration file

4. Explore the Counter Contract

Foundry initializes your project with a Counter contract in src/Counter.sol:

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

contract Counter {
    uint256 public number;

    function setNumber(uint256 newNumber) public {
        number = newNumber;
    }

    function increment() public {
        number++;
    }
}

This contract stores a number and allows you to set or increment it.

5. Compile the Contract

Compile your smart contracts with:

forge build

This command compiles all contracts in src/ and outputs artifacts to the out/ directory.

6. Run Tests

Foundry supports writing tests in Solidity (in the test/ directory). To run all tests:

forge test

You'll see output indicating which tests passed or failed. The default project includes a sample test for the Counter contract.

7. Deploying Your Contract

To deploy your contract to a Hyperion testnet , you'll need:

• An RPC URL
• A private key with testnet ETH

For Hyperion testnet, use these details:

Example deployment command for Hyperion testnet:

forge create --rpc-url https://hyperion-testnet.metisdevops.link \
  --private-key <YOUR_PRIVATE_KEY> \
  src/Counter.sol:Counter \
  --broadcast

Replace <YOUR_PRIVATE_KEY> with your actual private key. Never share your private key.

8. Interacting with Contracts

You can use cast to interact with deployed contracts, send transactions, or query data. For example, to read the number variable on Hyperion testnet:

cast call <CONTRACT_ADDRESS> "number()(uint256)" --rpc-url https://hyperion-testnet.metisdevops.link

Next Steps

• Add more complex functionality to your counter contract
• Implement events for better tracking
• Add access control mechanisms
• Set up continuous integration
• Add more comprehensive tests