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Quickstart: Creating a Transaction on OpStart

OpStack is a modular, open-source toolkit for building scalable and customizable layer-2 blockchains on Ethereum. This tutorial will guide you through the steps of creating a transaction on an OpStack chain named "OpStart".

Prerequisites​

  1. Ethereum Wallet: Ensure you have an Ethereum wallet (e.g., MetaMask).
  2. Test ETH: Obtain some test ETH for the Ethereum network used by OpStart (usually from a faucet).
  3. OpStart Node: Access to an OpStart node's endpoint (HTTP or WebSocket).
  4. Web3 Library: Install the Web3.js library.

Step 1: Setting Up Your Environment​

  1. Install Node.js and npm (if not already installed):

    sudo apt install nodejs
    sudo apt install npm

  2. Install Web3.js:

    npm install web3

  3. Set Up Your Project: Create a new directory for your project and navigate into it:

    mkdir opstart-transaction
    cd opstart-transaction

    Initialize a new Node.js project:

    npm init -y

    Install Web3.js:

    npm install web3

Step 2: Connecting to the OpStart Node​

Create a new JavaScript file, createTransaction.js, and set up the Web3 connection:

const Web3 = require('web3');

// Replace with your OpStart node's endpoint
const opstartNode = 'https://opstart-node-endpoint';

const web3 = new Web3(new Web3.providers.HttpProvider(opstartNode));

// Your wallet's private key
const privateKey = 'YOUR_PRIVATE_KEY';

// Your wallet's address
const walletAddress = 'YOUR_WALLET_ADDRESS';

// Recipient's address
const recipientAddress = 'RECIPIENT_WALLET_ADDRESS';

Step 3: Creating and Sending the Transaction​

Add the following code to create and send a transaction:

async function createTransaction() {
    // Get the current nonce
    const nonce = await web3.eth.getTransactionCount(walletAddress, 'latest');

    // Transaction details
    const tx = {
        from: walletAddress,
        to: recipientAddress,
        value: web3.utils.toWei('0.1', 'ether'), // Amount of ETH to send
        gas: 21000,
        nonce: nonce,
        chainId: 420 // Replace with your OpStart chain ID
    };

    // Sign the transaction
    const signedTx = await web3.eth.accounts.signTransaction(tx, privateKey);

    // Send the transaction
    web3.eth.sendSignedTransaction(signedTx.rawTransaction)
        .on('receipt', receipt => {
            console.log('Transaction successful with hash:', receipt.transactionHash);
        })
        .on('error', error => {
            console.error('Transaction failed:', error);
        });
}

// Execute the function
createTransaction();

Step 4: Running Your Script​

Run your script using Node.js:

node createTransaction.js

Step 5: Verifying the Transaction​

After running the script, you should see a transaction hash printed to the console. You can use this hash to verify the transaction on the OpStart block explorer or any tool that supports OpStack chains.

Conclusion​

You have successfully created and sent a transaction on an OpStack chain called OpStart. This tutorial covered the basics of setting up your environment, connecting to the OpStart node, creating and signing a transaction, and sending it to the network. You can now explore more advanced features of OpStack and Web3.js to build more complex applications.

Additional Resources​

If you have any questions or run into issues, feel free to ask for help on relevant forums or communities. Happy coding!