How to mint a music NFT: Dropping fire tunes with Chainstack IPFS storage

TLDR:

Creates a Music NFT using a custom ERC721 contract (via OpenZeppelin Wizard) with metadata pointing to audio and cover files on IPFS
Deploys contract with Hardhat to testnet; verifies it on Etherscan
Pins the audio and cover image plus NFT metadata using Chainstack IPFS Storage
Mints the NFT from your wallet, allowing you to see your music NFT on MetaMask/OpenSea with embedded audio

Main article

In the digital age, artists are constantly seeking innovative ways to share, monetize, and protect their work. Enter the world of non-fungible tokens (NFTs)—a revolutionary way for musicians to create, sell, and own their masterpieces. As the music industry evolves, NFTs are becoming the driving force behind a paradigm shift in how artists generate income and maintain control over their creations. The music industry has always been a hotbed of innovation and change, from vinyl records to streaming services. Now, the advent of blockchain technology and the rise of NFTs are opening up an entirely new frontier for musicians and music enthusiasts alike. With the potential to revolutionize how we create, own, and trade music, NFTs are rapidly becoming an essential tool for artists looking to embrace the digital era. But how does one go about minting a music NFT? If you’ve been wondering about this very question, you’ve come to the right place. In this comprehensive guide, we’ll walk you through the process step by step, demystifying the world of music NFTs and empowering you to join the revolution. So, whether you’re an aspiring musician, a dedicated collector, or simply curious about this exciting new development, read on and get ready to make some noise in the NFT space.

How to mint a music NFT?

Minting NFTs through coding can be slightly more challenging than relying on a marketplace platform to handle the process for you. However, it provides you with greater flexibility and allows you to engage with the core mechanics of minting. Let’s explore how you can get started:

Step 1: Get started with the basics

1.1: Obtain a node endpoint

Running your own node can be a time-consuming process. Instead, you can quickly and effortlessly deploy a node with Chainstack, saving both time and effort. To get started, visit the Chainstack website, create a free account, deploy a Sepolia node, and obtain its HTTPS endpoint. Don’t worry about your testnet choice, the code base in this tutorial is structured in a way that will allow you to switch between Sepolia, and Mainnet freely, without having to rewrite everything. If you’re unsure about the process, follow the steps in our easy-to-understand quickstart guide.

1.2: Install core dependencies

If you haven’t installed node.js yet, go ahead and do so. Once that’s done, you’ll need to set up a workspace for your codebase. Create a new directory in your preferred location and initialize your node.js project by entering the following commands in your CLI (command line interface):

npm init -y

The -y flag indicates that all the default values should be used without prompting the user for input.

And while you’re still on the topic of initializing your project, go ahead and do so for git, in case you haven’t done that already. To make this happen, download and install git, if it’s not present on your system yet, then execute the following in a freshly run CLI instance:

git init

Next, install the Hardhat library with the web3 and hardhat-verify plugins, which will provide you with the functionality required to interact with your node, as well as verify your deployed contract:

npm install --save-dev @nomiclabs/hardhat-web3 'web3' @nomicfoundation/hardhat-verify

After the installation is complete, initialize your Hardhat project for JavaScript with:

npx hardhat

Once the initialization is complete, you will find a hardhat.config.js file in your project root. Open it and replace the contents with the following:

// Process dependencies
require("@nomiclabs/hardhat-web3");
require("@nomicfoundation/hardhat-verify");

1.3: Securely store your secrets

To securely store all values, which are best left away from prying eyes, such as your endpoint you’ll utilize a .env file. But before you set off to create such a file, go ahead and install the dotenv package using npm via CLI:

npm i dotenv

With the package installed, create a .env file in your project root and transfer over your endpoint URL there as the first key-value pair. If you want to use all three Ethereum networks (Sepolia, and Mainnet) you can set it up like so:

SEPOLIA="YOUR_SEPOLIA_ENDPOINT"
MAINNET="YOUR_MAINNET_ENDPOINT"

This makes it possible for you to load the SEPOLIA, or MAINNET value from your .env file in any script in your project that has the dotenv dependency processed appropriately. So, go ahead and break the ice by adding require('dotenv').config(); in your hardhat.config.js script as early as possible. Referencing dotenv before any and all other dependencies prevents possible conflicts, which may arise due to an inappropriate loading order. Proceed by initializing each network with its corresponding endpoint in hardhat.config.js as the values for the url keys, using the dotenv process.env method. You can also set a PRIVATE_KEY value for the accounts keys already, considering you will be getting a new one in the next section. Here’s how your hardhat.config.js should look like, once you’ve set everything up correctly:

// Process dependencies
require("dotenv").config();
require("@nomiclabs/hardhat-web3");
require("@nomicfoundation/hardhat-verify");

// Define Hardhat settings
module.exports = {
  solidity: "0.8.17",
  networks: {
    mainnet: {
      url: process.env.MAINNET,
      accounts: [process.env.PRIVATE_KEY]
    },
    sepolia: {
      url: process.env.SEPOLIA,
      accounts: [process.env.PRIVATE_KEY]
    },
    sepolia: {
      url: process.env.SEPOLIA,
      accounts: [process.env.PRIVATE_KEY]
    },
  },
};

Before you continue, however, it is crucial to remember that you should NEVER upload your .env file to any public repository, as it will serve as a container for all your sensitive information moving forward. Apart from your endpoint URL, you will also store things like your private key inside the .env file, which could expose your entire wallet if leaked. Having this in mind, go ahead and create a .gitignore file if you don’t have one already, so you can add .env to it before you publish. Refer to the following example for how you can do that:

# dotenv environment variables file
.env
.env.test

1.4: Create a new wallet and fund it

Once the initialization is complete, create a new /scripts directory and add a new wallet.js file in it. When you’ve created the new script, include the following lines of code to initialize the necessary dependencies:

// Process dependencies
require('dotenv').config()
require("@nomiclabs/hardhat-web3");

Next, you will need to set up a function to create your wallet. To do this, you can use the web3.js method web3.eth.accounts.create();, just make sure you return the address and privateKey values at the end of your async function:

// Create a new wallet then return the address and private key
const createWallet = async () => {
    const wallet = web3.eth.accounts.create();
    return [wallet.address, wallet.privateKey];
}

Once entered, you will also need to create another async function that will fund your wallet with testnet ETH from the Chainstack faucet. To do this you will first need to take care of a few things:

Create a Chainstack API key and copy it, which will be similar to Bearer y0urChainstackAPIkeyHer3, then store it in your .env file as CHAINSTACK:
CHAINSTACK="Bearer YOUR_CHAINSTACK_API_KEY"
Install axios library to be able to send HTTP requests to the faucet:
npm i axios

Require axios at the end of your wallet.js dependencies like so:

// Process dependencies
require('dotenv').config()
require("@nomiclabs/hardhat-web3");
const axios = require('axios');

With that taken care of, you can move forward with your fundWallet function, by adding address and apiKey as its required parameters. Next, create a new const called apiUrl, add the faucet API URL, and place ${network.name} at the end of it to be able to select the right testnet version:

// Fund the wallet using the Chainstack faucet
const fundWallet = async (address, apiKey) => {
    const apiUrl = `https://api.chainstack.com/v1/faucet/${network.name}`;
}

Using the Hardhat network.name variable allows you to switch between networks with the --network parameter whenever you are running a particular script with Hardhat.

Hopping back to your fundWallet function, it is time for you to close it off with a try-catch loop that will contain your axios request to the Chainstack faucet. Inside the try part of the loop, add a new const called response, where you will set the axios settings and return the response:

// Fund the wallet using the Chainstack faucet
const fundWallet = async (address, apiKey) => {
    const apiUrl = `https://api.chainstack.com/v1/faucet/${network.name}`;

    try {
        const response = await axios.post(apiUrl, { address }, {
            headers: {
                'Authorization': apiKey,
                'Content-Type': 'application/json',
            },
        });
        return response.data;
    }

This creates a POST request to the Chainstack faucet apiURL with your address, your apiKey as the Authorization header, and application/json as the Content-Type. And with the try part of the loop taken care of, you can wrap up the entire thing by catching and then throwing an error, should it occur. Here’s how your wallet.js script should look like at this point:

// Process dependencies
require('dotenv').config()
require("@nomiclabs/hardhat-web3");
const axios = require('axios');

// Create a new wallet then return the address and private key
const createWallet = async () => {
    const wallet = web3.eth.accounts.create();
    return [wallet.address, wallet.privateKey];
}

// Fund the wallet using the Chainstack faucet
const fundWallet = async (address, apiKey) => {
    const apiUrl = `https://api.chainstack.com/v1/faucet/${network.name}`;

    try {
        const response = await axios.post(apiUrl, { address }, {
            headers: {
                'Authorization': apiKey,
                'Content-Type': 'application/json',
            },
        });
        return response.data;
    } catch (error) {
        throw error;
    }
};

But hey, hang on a minute! There is still something missing from your wallet.js script—some of the variables are not set yet and neither are the calls that will run the two functions you have set. So, go ahead and create them but do so in a new async function called main. And while you’re at it, why not add some visual feedback to make it easy for you to process their results. Since there is little new to learn with this function, let’s straight up recap with the full wallet.js script until now:

// Process dependencies
require('dotenv').config()
require("@nomiclabs/hardhat-web3");
const axios = require('axios');

// Create a new wallet then return the address and private key
const createWallet = async () => {
    const wallet = web3.eth.accounts.create();
    return [wallet.address, wallet.privateKey];
}

// Fund the wallet using the Chainstack faucet
const fundWallet = async (address, apiKey) => {
    const apiUrl = `https://api.chainstack.com/v1/faucet/${network.name}`;

    try {
        const response = await axios.post(apiUrl, { address }, {
            headers: {
                'Authorization': apiKey,
                'Content-Type': 'application/json',
            },
        });

        return response.data;
    } catch (error) {
        throw error;
    }
};

// Main function to generate a new wallet and fund it using the Chainstack faucet
const main = async () => {
    try {

        // Config for the Faucet API call
        const apiKey = process.env.CHAINSTACK;

        console.log('\nAttempting to generate new wallet...\n')
        const [address, privateKey] = await createWallet();

        console.log(`Created new wallet with address: ${address}\n`);
        console.log(`New private key: ${privateKey} === KEEP IT SAFE ===\n`);
        console.log(`Copy the following and replace the "WALLET" and "PRIVATE_KEY" lines in your ".env" file:\n\nWALLET="${address}" \nPRIVATE_KEY="${privateKey}"\n`);
        console.log(`Sending ${network.name} faucet request for address ${address}...\n`);
        const fundResponse = await fundWallet(address, apiKey);
				console.log(`Successfully funded ${address} on ${network.name} for ${fundResponse.amountSent}ETH.\n\nView transaction on Etherscan: ${fundResponse.transaction}\n`);
    } catch (error) {
        console.error('An error occurred:', error.response.data);
    }
}

// Don't forget to run the main function!
main();

With the wallet.js script fully set up, the time has come for you to launch it via CLI using Hardhat:

# Sepolia
npx hardhat run scripts/wallet.js --network sepolia

You will get the following response if you have the additional visual feedback applied:

Attempting to generate new wallet...

Created new wallet with address: 0x13a310e3FfAa420D317F4d51C85225FDEB8e6eAd

New private key: 0x70472ba98ccf4ab019cbd3f1124dd3cc95a46cd60f8465ba67e3163914287576 === KEEP IT SAFE ===

Copy the following and replace the "WALLET" and "PRIVATE_KEY" lines in your ".env" file:

WALLET="0x13a310e3FfAa420D317F4d51C85225FDEB8e6eAd"
PRIVATE_KEY="0x70472ba98ccf4ab019cbd3f1124dd3cc95a46cd60f8465ba67e3163914287576"

Sending sepolia faucet request for address 0x13a310e3FfAa420D317F4d51C85225FDEB8e6eAd...

Successfully funded 0x13a310e3FfAa420D317F4d51C85225FDEB8e6eAd on sepolia for 0.5ETH.

View transaction on Etherscan: https://sepolia.etherscan.io/tx/0x2827d3886ca45b63f2692caf3189fef67128825eaebc5c9ab0f6e7184deaf73a

Congrats, you have now created a wallet and funded it successfully with the Chainstack faucet! Your next step is to enter the two keys into your .env file as values for the WALLET and PRIVATE_KEY keys. You can also use a pre-existing wallet address with the appropriate private key attached to it, by setting them in your .env file instead.

1.5: Verify your wallet balance

Now it’s time to verify if your balance has been updated. Create a new file named balance.js within the /scripts directory and copy over the first two dependencies from your wallet.js script, without adding the one for axios. Then, create a new address constant and set its value to the WALLET you just copied in your .env file, using process.env.WALLET:

 // Process dependencies
require('dotenv').config();
require("@nomiclabs/hardhat-web3");

// Initialize your wallet address
const address = process.env.WALLET;

With that taken care of, go ahead and create an asynchronous function that will use the address constant as a parameter and within it call the web3.js getBalance method. Since it will take more time for your node to process this request than that of executing the rest of the function’s code locally, make sure you add await prior to the method:

// Define your get balance function
const getbal = async (address) => {

  // Call the web3.js getBalance method
  const balance = await web3.eth.getBalance(address);
};

In doing so you will prevent the rest of the code from processing before the method’s promise is resolved once a response is returned. By default, the getBalance method will return a very barebones balance value in wei, so go ahead and add some extra visual feedback by calling the web3.js fromWei method to convert the wei output to ETH units. Once ready, go ahead and wrap things up by calling your getbalfunction with the address parameter at the end of your script:

// Process dependencies
require('dotenv').config();
require("@nomiclabs/hardhat-web3");

// Initialize your wallet address
const address = process.env.WALLET;

// Define your get balance function
const getbal = async (address) => {

  // Call the web3.js getBalance method
  const balance = await web3.eth.getBalance(address);

  // Return your wallet balance in Wei and ETH on the selected network
  console.log(`\nChecking ${network.name} balance for address: ${address}...\n\nYour balance is: ${balance}Wei\nThis amounts to: ${web3.utils.fromWei(balance)}ETH\n`);
};

// Don't forget to run your get balance function!
getbal(address);

Once you’re ready, go ahead and run the script via Hardhat in CLI using the --network parameter:

npx hardhat run scripts/balance.js --network $NETWORK

Checking sepolia balance for address: 0x13a310e3FfAa420D317F4d51C85225FDEB8e6eAd...

Your balance is: 500000000000000000Wei
This amounts to: 0.5ETH

Step 2: Prepare and deploy the smart contract

2.1: Draft an NFT smart contract

Now that you’ve completed all the necessary preparations, it’s time to create your smart contract. While this might seem intimidating at first, you can rest easy knowing that OpenZeppelin provides pre-built, security-audited contract templates. The cherry on top? You can use their wizard to create a customized contract that perfectly fits your needs. For our sample project, we will be using the following settings:

OpenZeppelin Contract Wizard

Figure 1: music NFT project settings

Aside from the name and symbol, which are quite self-explanatory, we’ll include a Mintable option with Auto Increment Ids enabled. This feature allows privileged accounts (e.g., your account) to mint new tokens, which can represent new additions to your collection. We also need to enable the URI Storage option, as it allows us to attach media files like images to our NFTs. Additionally, we’ll incorporate the Ownable option to enable administrative actions. While there are more parameters available in the wizard, they fall outside the scope of this tutorial. However, don’t hesitate to experiment with them if you wish to explore additional functionalities beyond the basic ones we’ve implemented so far. Finally, ensure that the OpenZeppelin dependencies are available in your project by installing its contracts library with the following:

npm i @openzeppelin/contracts

2.2: Compile the minter smart contract

With your contract ready, copy the code from the OpenZeppelin wizard into a new file, such as MyMusicNFT.sol, or click Download in the top-right corner. Then, create a new directory called contracts in your project root and place your smart contract in it.

Hardhat automatically compiles a new contract when it needs it, without additional input from your end but you can also do that manually using npx hardhat compile. This will compile all contracts located in the contracts directory, so if you have more than one, they will all be process accordingly.

Before you move forward with deploying your compiled contract, however, there are some things to take care of first:

Create an Etherscan account and API key, so you can verify the contract once it is deployed.

Save the API key in your .env file as value for the ETHERSCAN key:

SEPOLIA="YOUR_SEPOLIA_ENDPOINT"
MAINNET="YOUR_MAINNET_ENDPOINT"
CHAINSTACK="Bearer YOUR_CHAINSTACK_API_KEY"
WALLET="YOUR_WALLET_ADDRESS"
PRIVATE_KEY="YOUR_WALLET_PRIVATE_KEY"
ETHERSCAN="YOUR_ETHERSCAN_API_KEY"

Create a deploy.js script in your /scripts directory and add the following:

// Process dependencies
require('dotenv').config();
require("@nomiclabs/hardhat-web3");
require("@nomicfoundation/hardhat-verify");
const fs = require('fs');
const path = require('path');
const address = process.env.WALLET;
const privKey = process.env.PRIVATE_KEY;

Apart from referencing the hardhat-verify library you installed earlier, there are two packages you haven’t encountered in this tutorial yet—fs and path, both of which ship by default with node.js. The former, fs, is a file system module, that allows you to interact with local files, while the latter is used for handling and transforming file paths. As the next step, create a few constants called contractName, artifactPath, contractArtifact, contractABI, and contractBIN. The first one will be used by Hardhat to determine which contract you will be interacting with, while the second and third to locate and read the compiled contract artifact. This artifact contains your smart contract’s ABI and its bytecode , or BIN.

ABI an BIN

The application binary interface (ABI) facilitates interaction between software modules, translating Solidity contract calls for Ethereum’s Virtual Machine (EVM) and decoding transaction data. On the other hand, bytecode (BIN) is the binary output of Solidity code and consists of machine-readable instructions including one-byte “opcodes”, hence the name.

The artifact, containing your smart contract’s ABI and BIN is automatically generated when you compile it with Hardhat as /artifacts/contracts/YourContractName.sol/YourContractName.json, where YourContractName is the name of your contract. In this tutorial’s case, it is MyFirstMusicNFT, so go ahead and set the contractName constant’s value to your smart contract’s actual name. To help your code discover the location of the artifact, you can use the path.resolve method with __dirname as the first parameter, and the JSON path mentioned in the paragraph above, preceded by .. to indicate the parent directory.

About `__dirname`

In node.js, __dirname is an environment variable that gives the absolute path to the directory of the currently running file. Unlike ./, which denotes the current directory of a file, or ../, which refers to its parent directory, __dirname always points to the precise directory where the executing file resides.

Then, go ahead and read the JSON file with the fs.readFileSync method as the first parameter but make sure you have set utf-8 as the encoding type in the second. Lastly, pass the entire thing as a JSON object by wrapping it with JSON.parse. Here’s how this part of your script should look like:

// Process dependencies
require('dotenv').config();
require("@nomiclabs/hardhat-web3");
require("@nomicfoundation/hardhat-verify");
const fs = require('fs');
const path = require('path');
const address = process.env.WALLET;
const privKey = process.env.PRIVATE_KEY;

// Replace 'MyFirstMusicNFT' with your contract's name.
const contractName = 'MyFirstMusicNFT';

// Find the compiled smart contract to get the ABI and bytecode
const artifactPath = path.resolve(__dirname, `../artifacts/contracts/${contractName}.sol/${contractName}.json`);
const contractArtifact = JSON.parse(fs.readFileSync(artifactPath, 'utf-8'));
const contractABI = contractArtifact.abi;
const contractBIN = contractArtifact.bytecode;

2.3: Deploy your smart contract

Next, it’s time for you to put together the rest of the deploy.js script by adding a new function to handle the actual deployment process. To do that, define a fresh asynchronous main function first and create a new contract object constant contractNFT by calling the web3.js Contract method with contractABI and address as parameters, respectively. Then, deploy the contractNFT contract object as a constant contractTX transaction object by applying the deploy method to it with a data parameter set to contractBIN.

// Create asynchronous function to deploy your contract
async function main() {
  console.log(`\nAttempting to deploy the ${contractName} contract on ${network.name} from: ${address}\n`);
  // Create new contract object
  const contractNFT = new web3.eth.Contract(contractABI, address);

  // Deploy contract object as a transaction
  const contractTX = await contractNFT.deploy({

    // Set transaction data as the contract bytecode
    data: contractBIN,
  });
}

Once you’ve set this up, proceed by creating a function to estimate the gas of the contract deployment transaction contractTX. To do that, just slap the web3.js estimateGas method at the back of the contractTX object, and add some relevant visual feedback. Then, continue by calling the web3.js signTransaction method with two parameters, the first being an object, and the second—privKey. Compose the object parameter using the key from set to address, data as contractTX with the encodeABI method applied to it, and gasCost as value for thegas one as the third.

// Estimate the gas costs needed to process the transaction
  const gasCost = await contractTX.estimateGas((err, gas) => {
    if (!err) console.log(`Estimated gas: ${gas}...`);
    else console.error(`Error estimating gas: ${err}...`);
  });

  // Sign the transaction
  const createTransaction = await web3.eth.accounts.signTransaction({

    // Define transaction parameters
    from: address,
    data: contractTX.encodeABI(),
    gas: gasCost,
  },
    privKey
  );

With this taken care of, your next step is to ask for a receipt with a createReceipt constant with value calling the web3.js sendSignedTransaction method with a single parameter, preceded by an await operator. Set the createTransaction constant as a value for it, apply the rawTransaction method to it, and then add some visual feedback to display the receipt as the closing statement for the entire deploy function. Don’t forget to run it either!

// Return transaction receipt
  const createReceipt = await web3.eth.sendSignedTransaction(
    createTransaction.rawTransaction
  );

  // Log contract address from receipt
  console.log(`\nContract successfully deployed on ${network.name} at: ${createReceipt.contractAddress} \n\nCopy the following line to your ".env" file:\n\n${network.name.toUpperCase()}_CONTRACT="${createReceipt.contractAddress}"\n`);

Now, it’s time to verify your contract with Hardhat after it has been deployed. But considering it takes roughly 5 blocks of confirmations before you are able to do that, let’s set up a function to wait for the appropriate time before launching the verification. The function in itself just checks the current block using the web3.js getBlockNumber method in a given interval, so just copy over the following outside the main function loop:

// Wait for `n` blocks function
async function waitForBlocks(n) {

  // Get the latest block number
  let latestBlockNumber = await web3.eth.getBlockNumber();
  console.log(`Current block number: ${latestBlockNumber}...`);

  // Calculate the block number to wait for
  let targetBlockNumber = latestBlockNumber + n;
  console.log(`Waiting until block number: ${targetBlockNumber}...`);

  // Check for the right block at a given interval
  return new Promise((resolve) => {
    let interval = setInterval(async () => {
      latestBlockNumber = await web3.eth.getBlockNumber();
      console.log(`Checked latest block number: ${latestBlockNumber}...`);

      // Check if the current block number matches the one to wait for
      if (latestBlockNumber >= targetBlockNumber) {
        clearInterval(interval);
        console.log(`Target block reached: ${latestBlockNumber}...\n`);
        resolve();
      }
    }, 5000);  // Set polling interval as per your need.
  });
}

Last, you need to set up the verification function itself, so create a new asynchronous verifyContract function and inside it call the waitForBlocks and run("verify:verify"), while waiting for them to execute first. Make sure to also add the address and constructorArguments parameters, with createReceipt.contractAddress as value for the former and a blank array [] as one for the latter:

// Verify the contract
  async function verifyContract() {
    console.log("Verifying contract in 5 blocks...\n");

    // Wait for 5 blocks before running verification
    await waitForBlocks(5);
    await run("verify:verify", {
      address: createReceipt.contractAddress,
      constructorArguments: [],
    });
    console.log("\nContract deployed and verified!\n");
  }
  verifyContract();
}

That’s it! Now all you have to do is run the deploy.js script via CLI with npx hardhat run scripts/deploy.js --network $NETWORK to have your very own smart contract deployed on the testnet of your choice. But still, the steps that led you here were indeed a tad bit more complex than what you had done so far in this tutorial, so let’s recap by reviewing the entire deploy script’s code:

// Process dependencies
require('dotenv').config();
require("@nomiclabs/hardhat-web3");
require("@nomicfoundation/hardhat-verify");
const fs = require('fs');
const path = require('path');
const address = process.env.WALLET;
const privKey = process.env.PRIVATE_KEY;

// Replace 'MyFirstMusicNFT' with your contract's name.
const contractName = 'MyFirstMusicNFT';

// Find the compiled smart contract to get the ABI and bytecode
const artifactPath = path.resolve(__dirname, `../artifacts/contracts/${contractName}.sol/${contractName}.json`);
const contractArtifact = JSON.parse(fs.readFileSync(artifactPath, 'utf-8'));
const contractABI = contractArtifact.abi;
const contractBIN = contractArtifact.bytecode;

// Create asynchronous function to deploy your contract
async function main() {
  console.log(`\nAttempting to deploy the ${contractName} contract on ${network.name} from: ${address}\n`);
  // Create new contract object
  const contractNFT = new web3.eth.Contract(contractABI, address);

  // Deploy contract object as a transaction
  const contractTX = await contractNFT.deploy({

    // Set transaction data as the contract bytecode
    data: contractBIN,
  });

  // Estimate the gas costs needed to process the transaction
  const gasCost = await contractTX.estimateGas((err, gas) => {
    if (!err) console.log(`Estimated gas: ${gas}...`);
    else console.error(`Error estimating gas: ${err}...`);
  });

  // Sign the transaction
  const createTransaction = await web3.eth.accounts.signTransaction({

    // Define transaction parameters
    from: address,
    data: contractTX.encodeABI(),
    gas: gasCost,
  },
    privKey
  );

  // Return transaction receipt
  const createReceipt = await web3.eth.sendSignedTransaction(
    createTransaction.rawTransaction
  );

  // Log contract address from receipt
  console.log(`\nContract successfully deployed on ${network.name} at: ${createReceipt.contractAddress} \n\nCopy the following line to your ".env" file:\n\n${network.name.toUpperCase()}_CONTRACT="${createReceipt.contractAddress}"\n`);

  // Verify the contract
  async function verifyContract() {
    console.log("Verifying contract in 5 blocks...\n");

    // Wait for 5 blocks before running verification
    await waitForBlocks(5);
    await run("verify:verify", {
      address: createReceipt.contractAddress,
      constructorArguments: [],
    });
    console.log("\nContract deployed and verified!\n");
  }
  verifyContract();
}

// Wait for `n` blocks function
async function waitForBlocks(n) {

  // Get the latest block number
  let latestBlockNumber = await web3.eth.getBlockNumber();
  console.log(`Current block number: ${latestBlockNumber}...`);

  // Calculate the block number to wait for
  let targetBlockNumber = latestBlockNumber + n;
  console.log(`Waiting until block number: ${targetBlockNumber}...`);

  // Check for the right block at a given interval
  return new Promise((resolve) => {
    let interval = setInterval(async () => {
      latestBlockNumber = await web3.eth.getBlockNumber();
      console.log(`Checked latest block number: ${latestBlockNumber}...`);

      // Check if the current block number matches the one to wait for
      if (latestBlockNumber >= targetBlockNumber) {
        clearInterval(interval);
        console.log(`Target block reached: ${latestBlockNumber}...\n`);
        resolve();
      }
    }, 5000);  // Set polling interval as per your need.
  });
}

// Don't forget to run your main function! Add error handling too
main().catch((error) => {
  console.error(error);
  process.exitCode = 1;
});

Congratulations! Should you have followed the steps so far correctly, your first NFT contract is now live on the testnet of your choice! With that milestone achieved, it is time to define the metadata properties of your NFT prior to minting.

Step 3: Pin the metadata and mint your NFTs

3.1: Getting started with Chainstack IPFS Storage

Before you can mint any NFT, you will first need to pin all relevant media files to the Interplanetary File System (IPFS). Thanks to this, you won’t have to rely on the availability of any centralized provider, instead having it permanently accessible. In IPFS, uploading is adding a file to the network, while pinning is ensuring its persistent availability by preventing its removal on a specific node. To make the entire process a real walk in the park, you can use Chainstack IPFS Storage, which will provide a seamless interface and API for you to do that. You can use the interface to create the bucket and folder that you need to pin the files manually, or follow this process to do so via the API:

Sign in to your Chainstack account via the console and select IPFS Storage from the navigation on the left.
Click the Create bucket and enter a name of your choice.
Inside the bucket, click New folder with a name of your choice.
Open the folder and bucket and examine the URL in the address bar for each of them.
Copy the bucket ID starting with BUCK, for example, BUCK-1337-8085-1337.
Copy the folder ID starting with FOLD, for example, FOLD-1337-8085-1337.
Paste the three values in your .env file for the BUCKET_ID, FOLDER_ID, and CHAINSTACK keys like so:

BUCKET_ID="BUCK-1337-8085-1337"
FOLDER_ID="FOLD-1337-8085-1337"

3.2: Pin your NFT media with Chainstack IPFS Storage

With the prerequisites taken care of, it is time for you to pin the media files with Chainstack IPFS Storage. In the tutorial repo, you will find a tutorial audio file and cover image in the src directory that you can use freely to test the waters. Should you prefer to pin them with Chainstack IPFS Storage via the interface manually, you can do so already and jump to the next step, where you will set up the JSON metadata. Otherwise, it is time for you to create a new pin.js file to do that via the API. To get started with the new pin script, process the dependencies first. You will need the dotenv, fs, axios, and the FormData packages, the latter of which you can install with the following command:

npm install form-data

Here’s how the start of the script should look like:

// Process dependencies
require('dotenv').config();
const fs = require('fs');
const axios = require('axios');
const FormData = require('form-data');

Next, define the location of the media files you will be pinning with Chainstack IPFS Storage via the API like so:

// Define the media files to be pinned with Chainstack IPFS Storage
const content = [
  {
    file: fs.createReadStream("./src/(Tutorial) My First Music NFT Cover.png"),
    title: "(Tutorial) My First Music NFT Cover.png"
  },
  {
    file: fs.createReadStream("./src/(Tutorial) PetarISFire - Chainstackwave.mp3"),
    title: "(Tutorial) PetarISFire - Chainstackwave.mp3"
  }
];

Once ready, it is time for you to define a new asynchronous addFiles function as a constant with source and single = false as the two parameters it seeks:

// Define a function to pin files with Chainstack IPFS Storage
const addFiles = async (source, single = false) => {
}

The second parameter single = false will serve to differentiate between pinning single and multiple files, as the API URLs for them are not the same. Set up the differentiation in the code like so:

  // Differentiate between pinning single and multiple files
  const url = single
    ? "https://api.chainstack.com/v1/ipfs/pins/pinfile"
    : "https://api.chainstack.com/v1/ipfs/pins/pinfiles";

Next, define a new data constant with a value equal to new FormData() and follow up with an if-else statement, checking for the state of the single parameter:

  // Define the pin metadata
  const data = new FormData();
  if (single) {
} else {
}

Inside the if statement, add some visual feedback to display which file you are attempting to pin by using the JSON.stringify method with the source[0].title value. Afterward, add the bucket_id, folder_id, file, and title to the data object via the append method. You can load the bucket_id and folder_id values from your .env file by setting them as the first parameter for the append method and using process.env.BUCKET_ID and process.env.FOLDER_ID, respectively as the second. In turn, do so for the file and title values but referencing source[0].file and source[0].title accordingly:

  // Define the pin metadata
  const data = new FormData();
  if (single) {
    console.log('Attempting to pin ' + JSON.stringify(source[0].title) + ' with Chainstack IPFS Storage...');
    data.append('bucket_id', process.env.BUCKET_ID);
    data.append('folder_id', process.env.FOLDER_ID);
    data.append('file', source[0].file);
    data.append('title', source[0].title);
  } else {
  }

The process is relatively similar for the else part of the statement, the only difference being that you need to use the forEach method to make sure all entries are referenced correctly:

  // Define the pin metadata
  const data = new FormData();
  if (single) {
    console.log('Attempting to pin ' + JSON.stringify(source[0].title) + ' with Chainstack IPFS Storage...');
    data.append('bucket_id', process.env.BUCKET_ID);
    data.append('folder_id', process.env.FOLDER_ID);
    data.append('file', source[0].file);
    data.append('title', source[0].title);
  } else {
    source.forEach((file) => {
      console.log('Attempting to pin ' + JSON.stringify(file.title) + ' with Chainstack IPFS Storage...');
      data.append('bucket_id', process.env.BUCKET_ID);
      data.append('folder_id', process.env.FOLDER_ID);
      data.append('file', file.file);
      data.append('title', file.title);
    });
  }

Once ready, proceed by creating a new config constant, which will set up the axios configuration. Here you will also make a reference to your Chainstack API authorization token in a fashion similar to this:

  // Define the Axios configuration
  const config = {
    method: 'POST',
    url: url,
    headers: {
      "Content-Type": 'multipart/form-data;',
      "Authorization": process.env.CHAINSTACK,
      ...data.getHeaders()
    },
    data: data
  };

Next, create a new response constant which will store the axios response, once again differentiating between single and multiple files:

  // Store the Axios response
  const response = await axios(config);
  if (single) {
    console.log(`File successfully pinned with Chainstack IPFS Storage with public ID: ${response.data.id}\\n`);
    return JSON.stringify(response.data.id);
  } else {
    const pubIDs = response.data.map((item) => item.id);
    console.log(`Files successfully pinned with Chainstack IPFS Storage with public IDs: ${pubIDs.join(', ')}\\n`);
    return pubIDs;
  }
};

With the addFiles function successfully set up, it is time to do so for the findCIDs one. Its purpose will be to obtain the content IDs (CIDs) of the files you have pinned, which are unique identifiers that allow universal access via any IPFS client. So, go ahead and create it as an asynchronous function by defining a new findCIDs constant and set fileID and single = false as the two parameters it would accept. Then, proceed by removing possible excess characters like so:

// Define a function to find CIDs for files pinned with Chainstack IPFS Storage
const findCIDs = async (fileID, single = false) => {
  if (single) {
    fileID = fileID.replace(/"/g, '');
    fileID = [fileID];
  }
}

It is quite possible that the CID will not be ready when your script moves on to find them, so let’s set up a redundancy process that will automatically retry the search. Start by defining a new maxRetries constant, as well as a retryTimeout one, setting the former’s value to 5 and the latter to 22000. Simply put, this will make the function retry for a maximum of 3 times with an 11-second timeout between each retry. Next, create an if-else statement with the !single parameter in the if part. Inside it, create a new cid and name temporary array variables. After that, create a for loop that will use the push method to store the CID and title values of the freshly pinned files:

  // Define the maximum retries and the timeout between retries
  const maxRetries = 5;
  const retryTimeout = 22000;

  if (!single) {
    let cid = [];
    let name = [];

    // Loop through all the pinned files
    for (var i = 0; i < fileID.length; i++) {

      // Get the CID and filename for the file
      const result = await findCIDs(fileID[i], true);
      cid.push(result[0]);
      name.push(result[1]);
    }

    // Print the CIDs found and return the cid and name values
    console.log('All CIDs found:' + cid + '\\n');
    return [cid, name];
  } else {
  }

The rest of the function follows a similar logic but additionally features the retry loop, the axios configuration, as well as some error-checking code. Here’s how the entire findCIDs function should look like in the end:

// Define a function to find CIDs for files pinned with Chainstack IPFS Storage
const findCIDs = async (fileID, single = false) => {
  if (single) {
    fileID = fileID.replace(/"/g, '');
    fileID = [fileID];
  }

  // Define the maximum retries and the timeout between retries
  const maxRetries = 3;
  const retryTimeout = 11000;

  if (!single) {
    let cid = [];
    let name = [];

    // Loop through all the pinned files
    for (var i = 0; i < fileID.length; i++) {

      // Get the CID and filename for the file
      const result = await findCIDs(fileID[i], true);
      cid.push(result[0]);
      name.push(result[1]);
    }

    // Print the CIDs found and return the cid and name values
    console.log('All CIDs found:' + cid + '\\n');
    return [cid, name];
  } else {
    let cid;
    let name;
    let retries = 0;

    // Set up the retry loop
    while (retries < maxRetries) {
      try {
        console.log('Attempting to find CID using public ID: ' + fileID + ' with Chainstack IPFS Storage...');

        // Define the Axios configuration
        const url = "https://api.chainstack.com/v1/ipfs/pins/" + fileID;
        var config = {
          method: 'GET',
          url: url,
          headers: {
            "Content-Type": 'text/plain',
            "Authorization": process.env.CHAINSTACK,
          },
        };

        // Store the Axios response
        const response = await axios(config);
        console.log('CID found:' + response.data.cid + ' Filename: ' + response.data.title + '\\n');

        cid = response.data.cid;
        name = response.data.title;

        // Throw an error if the cid and name values are not valid
        if (cid != null && cid !== 'error' && name != null && name !== 'error') {
          break;
        } else {

          // Throw an error if the CID and filename are not valid
          throw new Error('CID or name values are not valid.');
        }
      } catch (error) {
        console.error(`Error in findCIDs: ${error.message}. Attempting to retry...\\n`);

        // Retry after the timeout if unsuccessful
        retries++;
        await new Promise((resolve) => setTimeout(resolve, retryTimeout));
      }
    }
    return [cid, name];
  }
};

Once the CIDs are successfully fetched with the previous function, you will need to write them to a JSON file along with the rest of the metadata of your NFT. Said JSON file will then be used to mint an NFT with the appropriate contents. So, go ahead and create a new asynchronous writeJSON function as a constant with the pinCID and pinName parameters as the ones it should accept. Create new temporary audioIPFS and coverIPFS variables and then an if-else statement with pinCID && pinName as its parameters. Inside the if statement, create a for loop which will piece together the appropriate URLs of your media pins:

// Define a function to write the metadata to a .json file
const writeJSON = async (pinCID, pinName) => {
  let audioIPFS;
  let coverIPFS;
  if (pinCID && pinName) {
    for (var i = 0; i < pinName.length; i++) {
      if (pinName[i].includes('mp3')) {
        audioIPFS = "https://ipfsgw.com/ipfs/" + pinCID[i];
      } else {
        coverIPFS = "https://ipfsgw.com/ipfs/" + pinCID[i];
      }
    }
  }
}

In this tutorial, the URLs are pieced together using the Chainstack IPFS Storage gateway ipfsgw.com which will make your pins available faster, however, it is generally recommended to use ipfs:// for truly universal access, even if it takes much longer to propagate this way. That being said, finish off the rest of the function by writing the metadata you collected earlier to a JSON file in the src directory. The entire writeJSON function should be set up in a fashion similar to this:

// Define a function to write the metadata to a .json file
const writeJSON = async (pinCID, pinName) => {
  let audioIPFS;
  let coverIPFS;
  if (pinCID && pinName) {
    for (var i = 0; i < pinName.length; i++) {
      if (pinName[i].includes('mp3')) {
        audioIPFS = "https://ipfsgw.com/ipfs/" + pinCID[i];
      } else {
        coverIPFS = "https://ipfsgw.com/ipfs/" + pinCID[i];
      }
    }

    // Write the metadata to the file ./src/NFTmetadata.json
    fs.writeFileSync('./src/NFTmetadata.json', JSON.stringify({
      "description": "My first music NFT mint.",
      "external_url": "https://chainstack.com/nfts/",
      "image": coverIPFS,
      "animation_url": audioIPFS,
      "name": "PetarISFire - Chainstackwave"
    }));

    let jsonMeta;
    if (fs.existsSync('./src/NFTmetadata.json')) {
      jsonMeta = {
        file: fs.createReadStream('./src/NFTmetadata.json'),
        title: "NFTmetadata.json"
      };
    }
    return jsonMeta;
  }
};

Lastly, create a new asynchronous pinNFT function that will queue all the relevant functions in the correct order to have your media files and metadata JSON ready for minting:

// Define the main function that executes all necessary functions to pin the NFT metadata
const pinNFT = async () => {
  try {
    const ids = await addFiles(content);
    await new Promise((resolve) => setTimeout(resolve, 5000));

    const [pinCID, pinName] = await findCIDs(ids);
    await new Promise((resolve) => setTimeout(resolve, 5000));

    const jsonMeta = await writeJSON(pinCID, pinName);
    await new Promise((resolve) => setTimeout(resolve, 5000));

    const id = await addFiles([jsonMeta], true);
    await new Promise((resolve) => setTimeout(resolve, 5000));

    const jsonCID = await findCIDs(id, true);
    console.log('NFT metadata successfully pinned with Chainstack IPFS Storage!\\n');
    console.log('Copy this URL and set it as value for the "metadata" variable in the "mint.js" script file:\\n' + 'https://ipfsgw.com/ipfs/' + jsonCID);
  } catch (error) {
    console.error('Error during NFT pinning:', error.message);
  }
};

//Don't forget to call the main function!
pinNFT();

That’s it! You should now have a fully working script that will pin your media files, write the relevant metadata to JSON, pin said JSON, and have everything ready for minting automatically, even if it takes a couple of retries to do so. Don’t forget to run the pin.js script via CLI, so you can watch the fireworks!

If the script returns Error during NFT pinning: Request failed with status code 400 as response.

If you encounter this error, there is some degree of duplication with existing files you have pinned previously.To resolve it, you must either set new filenames and titles for the interrupted pins, or delete the previous ones.Do note that once you delete them, any previously minted NFTs using them as source for metadata will no longer display correctly and will be left as blank containers permanently.

And considering this has been the most complex script you have set up until now (and the rest of the tutorial), it is certainly wise to recap with the full pin.js code:

// Process dependencies
require('dotenv').config();
const fs = require('fs');
const axios = require('axios');
const FormData = require('form-data');

// Define the media files to be pinned
const content = [
  {
    file: fs.createReadStream("./src/(Tutorial) My First Music NFT Cover.png"),
    title: "(Tutorial) My First Music NFT Cover.png"
  },
  {
    file: fs.createReadStream("./src/(Tutorial) PetarISFire - Chainstackwave.mp3"),
    title: "(Tutorial) PetarISFire - Chainstackwave.mp3"
  }
];

// Define a function to pin files with Chainstack IPFS Storage
const addFiles = async (source, single = false) => {

  // Differentiate between pinning single and multiple files
  const url = single
    ? "https://api.chainstack.com/v1/ipfs/pins/pinfile"
    : "https://api.chainstack.com/v1/ipfs/pins/pinfiles";

  // Define the pin metadata
  const data = new FormData();
  if (single) {
    console.log('Attempting to pin ' + JSON.stringify(source[0].title) + ' with Chainstack IPFS Storage...');
    data.append('bucket_id', process.env.BUCKET_ID);
    data.append('folder_id', process.env.FOLDER_ID);
    data.append('file', source[0].file);
    data.append('title', source[0].title);
  } else {
    source.forEach((file) => {
      console.log('Attempting to pin ' + JSON.stringify(file.title) + ' with Chainstack IPFS Storage...');
      data.append('bucket_id', process.env.BUCKET_ID);
      data.append('folder_id', process.env.FOLDER_ID);
      data.append('file', file.file);
      data.append('title', file.title);
    });
  }

  // Define the Axios configuration
  const config = {
    method: 'POST',
    url: url,
    headers: {
      "Content-Type": 'multipart/form-data;',
      "Authorization": process.env.CHAINSTACK,
      ...data.getHeaders()
    },
    data: data
  };

  // Store the Axios response
  const response = await axios(config);
  if (single) {
    console.log(`File successfully pinned with Chainstack IPFS Storage using public ID: ${response.data.id}\\n`);
    return JSON.stringify(response.data.id);
  } else {
    const pubIDs = response.data.map((item) => item.id);
    console.log(`Files successfully pinned with Chainstack IPFS using public IDs: ${pubIDs.join(', ')}\\n`);
    return pubIDs;
  }
};

// Define a function to find CIDs for files uploaded to IPFS
const findCIDs = async (fileID, single = false) => {
  if (single) {
    fileID = fileID.replace(/"/g, '');
    fileID = [fileID];
  }

  // Define the maximum retries and the timeout between retries
  const maxRetries = 3;
  const retryTimeout = 11000;

  if (!single) {
    let cid = [];
    let name = [];

    // Loop through all the uploaded files
    for (var i = 0; i < fileID.length; i++) {

      // Get the CID and filename for the file
      const result = await findCIDs(fileID[i], true);
      cid.push(result[0]);
      name.push(result[1]);
    }

    // Print the CIDs found and return the cid and name values
    console.log('All CIDs found:' + cid + '\\n');
    return [cid, name];
  } else {
    let cid;
    let name;
    let retries = 0;

    // Set up the retry loop
    while (retries < maxRetries) {
      try {
        console.log('Attempting to find CID via public ID: ' + fileID + ' on Chainstack IPFS...');

        // Define the Axios configuration
        const url = "https://api.chainstack.com/v1/ipfs/pins/" + fileID;
        var config = {
          method: 'GET',
          url: url,
          headers: {
            "Content-Type": 'text/plain',
            "Authorization": process.env.CHAINSTACK,
          },
        };

        // Store the Axios response
        const response = await axios(config);
        console.log('CID found:' + response.data.cid + ' Filename: ' + response.data.title + '\\n');

        cid = response.data.cid;
        name = response.data.title;

        // Throw an error if the cid and name values are not valid
        if (cid != null && cid !== 'error' && name != null && name !== 'error') {
          break;
        } else {

          // Throw an error if the CID and filename are not valid
          throw new Error('CID or name values are not valid.');
        }
      } catch (error) {
        console.error(`Error in findCIDs: ${error.message}. Attempting to retry...\\n`);

        // Retry after the timeout if unsuccessful
        retries++;
        await new Promise((resolve) => setTimeout(resolve, retryTimeout));
      }
    }
    return [cid, name];
  }
};

// Define a function to write the metadata to a .json file
const writeJSON = async (uploadCID, uploadName) => {
  let audioIPFS;
  let coverIPFS;
  if (uploadCID && uploadName) {
    for (var i = 0; i < uploadName.length; i++) {
      if (uploadName[i].includes('mp3')) {
        audioIPFS = "https://ipfsgw.com/ipfs/" + uploadCID[i];
      } else {
        coverIPFS = "https://ipfsgw.com/ipfs/" + uploadCID[i];
      }
    }

    // Write the metadata to the file ./src/NFTmetadata.json
    fs.writeFileSync('./src/NFTmetadata.json', JSON.stringify({
      "description": "My first music NFT mint.",
      "external_url": "https://chainstack.com/nfts/",
      "image": coverIPFS,
      "animation_url": audioIPFS,
      "name": "PetarISFire - Chainstackwave"
    }));

    let jsonMeta;
    if (fs.existsSync('./src/NFTmetadata.json')) {
      jsonMeta = {
        file: fs.createReadStream('./src/NFTmetadata.json'),
        title: "NFTmetadata.json"
      };
    }
    return jsonMeta;
  }
};

// Define the main function that executes all necessary functions to upload the NFT metadata
const uploadNFT = async () => {
  try {
    const ids = await addFiles(content);
    await new Promise((resolve) => setTimeout(resolve, 5000));

    const [uploadCID, uploadName] = await findCIDs(ids);
    await new Promise((resolve) => setTimeout(resolve, 5000));

    const jsonMeta = await writeJSON(uploadCID, uploadName);
    await new Promise((resolve) => setTimeout(resolve, 5000));

    const id = await addFiles([jsonMeta], true);
    await new Promise((resolve) => setTimeout(resolve, 5000));

    const jsonCID = await findCIDs(id, true);
    console.log('NFT metadata successfully uploaded to Chainstack IPFS!\\n');
    console.log('Copy this URL and set it as value for the "metadata" variable in the "mint.js" script file:\\n' + 'https://ipfsgw.com/ipfs/' + jsonCID);
  } catch (error) {
    console.error('Error during NFT upload:', error.message);
  }
};

//Don't forget to call the main function!
uploadNFT();

3.3: Create the script for minting

By the time you reach this step, you should have successfully pinned your NFT media files with Chainstack IPFS Storage, and have their CIDs referenced in a JSON file that was also pinned there. The JSON file must contain an image key to store the NFT cover, an animation_url one for the audio file, name for the track title, and optionally a description, as well as an external_url for a link to your profile for example. It should look similar to this:

{
  "description": "My first music NFT mint.",
  "external_url": "https://chainstack.com/nfts/",
  "image": "https://ipfsgw.com/ipfs/QmfVBC87qZyn81Z68ntCkTNehQwdEFr3ZPCnVDTXjENxUT",
  "animation_url": "https://ipfsgw.com/ipfs/QmPv19dddmwp8BcoaxFmqZjhsps9wKVNubyYtpT2htxfTd",
  "name": "PetarISFire - Chainstackwave"
}

If that is indeed the case, you can move forward by creating a new mint.js file inside the scripts directory for the minting script. Begin by processing the dependencies for the dotenv, hardhat-web3, and fs modules. Proceed by initializing your wallet address, private key, deployed smart contract ABI, and JSON metadata URL, as well as the appropriate deployed contract address for each network via a simple if loop:

// Process dependencies
require('dotenv').config();
require("@nomiclabs/hardhat-web3");
const fs = require('fs');
const path = require('path');

// Initialize your wallet address and private key
const address = process.env.WALLET;
const privKey = process.env.PRIVATE_KEY;

// Initialize your deployed smart contract address for the selected network
let contractAdrs;
if (network.name == 'sepolia') {
  const contractENV = process.env.SEPOLIA_CONTRACT
  contractAdrs = contractENV;
} else if (network.name == 'sepolia') {
  const contractENV = process.env.SEPOLIA_CONTRACT;
  contractAdrs = contractENV;
} else {
  const contractENV = process.env.MAINNET_CONTRACT;
  contractAdrs = contractENV;
}

// Replace 'MyFirstMusicNFT' with your contract's name.
const contractName = 'MyFirstMusicNFT';

// Find the compiled smart contract to get the ABI
const artifactPath = path.resolve(__dirname, `../artifacts/contracts/${contractName}.sol/${contractName}.json`);
const contractArtifact = JSON.parse(fs.readFileSync(artifactPath, 'utf-8'));
const contractABI = contractArtifact.abi;

// Initialize the JSON metadata URL
const metadata = "https://ipfsgw.com/ipfs/QmX5mrBWukdWVByxnoUS4GJTysVBFjjoVg1fgSjExNV7Dd"

Then, create a new contract object and set the interactions origin to the owner address. This is crucial for the successful execution of the script, as earlier you set up the contract to allow minting only from the owner address. Without the correct from parameter it will return an error.

// Create a new contract object and set interactions origin to the owner address
const contractObj = new web3.eth.Contract(contractABI, contractAdrs, {
  from: address,
});

Next, create a gas estimation function like the one in the scripts/deploy.js using the web3.js estimateGas method with the safeMint method of your contract as its target:

// Define a gas estimation function
const gasEstimate = async () => {
  return await contractObj.methods.safeMint(address, metadata).estimateGas();
};

With that taken care of, move forward by defining a new asynchronous startMint function as a constant. Inside it, start by adding some visual feedback for the mint address target and the estimate response like so:

// Define a minting function
const startMint = async () => {
  console.log(`\nAttempting to mint on ${network.name} to: ${address}...\n`);

  // Estimate the gas costs needed to process the transaction
  const gasCost = await contractObj.methods.safeMint(address, metadata).estimateGas((err, gas) => {
    if (!err) console.log(`Estimated gas: ${gas}...\n`);
    else console.error(`Error estimating gas: ${err}...\n`);
  });
}

Continue the function by defining the transaction details and signing it with the web3.js signTransaction method, using as the first parameter an object with the address value for the from key, the contractAdrs one for to. Then, for data, call the contract object’s safeMint method with the encodeABI method attached to it, and gas set to gasCost. Use the privKey constant as the second parameter for a final result like this:

// Define the transaction details and sign it
  const mintTX = await web3.eth.accounts.signTransaction(
    {
      from: address,
      to: contractAdrs,
      data: contractObj.methods.safeMint(address, metadata).encodeABI(),
      gas: gasCost,
    },
    privKey,
  );

Lastly, make sure you get the transaction receipt by creating a createReceipt function like the following and call the startMint function to truly make the mix complete:

// Process dependencies
require('dotenv').config();
require("@nomiclabs/hardhat-web3");
const fs = require('fs');
const path = require('path');

// Initialize your wallet address and private key
const address = process.env.WALLET;
const privKey = process.env.PRIVATE_KEY;

// Initialize your deployed smart contract address for the selected network
let contractAdrs;
if (network.name == 'sepolia') {
  const contractENV = process.env.SEPOLIA_CONTRACT
  contractAdrs = contractENV;
} else if (network.name == 'sepolia') {
  const contractENV = process.env.SEPOLIA_CONTRACT;
  contractAdrs = contractENV;
} else {
  const contractENV = process.env.MAINNET_CONTRACT;
  contractAdrs = contractENV;
}

// Replace 'MyFirstMusicNFT' with your contract's name.
const contractName = 'MyFirstMusicNFT';

// Find the compiled smart contract to get the ABI
const artifactPath = path.resolve(__dirname, `../artifacts/contracts/${contractName}.sol/${contractName}.json`);
const contractArtifact = JSON.parse(fs.readFileSync(artifactPath, 'utf-8'));
const contractABI = contractArtifact.abi;

// Initialize the JSON metadata URL
const metadata = "https://ipfsgw.com/ipfs/QmX5mrBWukdWVByxnoUS4GJTysVBFjjoVg1fgSjExNV7Dd"

// Create a new contract object and set interactions origin to the owner address
const contractObj = new web3.eth.Contract(contractABI, contractAdrs, {
  from: address,
});

// Define a minting function
const startMint = async () => {
  console.log(`\nAttempting to mint on ${network.name} to: ${address}...\n`);

  // Estimate the gas costs needed to process the transaction
  const gasCost = await contractObj.methods.safeMint(address, metadata).estimateGas((err, gas) => {
    if (!err) console.log(`Estimated gas: ${gas}...\n`);
    else console.error(`Error estimating gas: ${err}...\n`);
  });

  // Define the transaction details and sign it
  const mintTX = await web3.eth.accounts.signTransaction(
    {
      from: address,
      to: contractAdrs,
      data: contractObj.methods.safeMint(address, metadata).encodeABI(),
      gas: gasCost,
    },
    privKey,
  );

  // Get transaction receipt
  const createReceipt = await web3.eth.sendSignedTransaction(mintTX.rawTransaction);

  // Provide appropriate network for Etherscan link
  if (network.name !== 'mainnet'){
  console.log(`NFT successfully minted on ${network.name} with hash: ${createReceipt.transactionHash}\n\nView the transaction on Etherscan: https://${network.name}.etherscan.io/tx/${createReceipt.transactionHash}\n`);
  } else {
    console.log(`NFT successfully minted on ${network.name} with hash: ${createReceipt.transactionHash}\n\nView the transaction on Etherscan: https://etherscan.io/tx/${createReceipt.transactionHash}\n`);
  }
};

// Don't forget to run the main function!
startMint();

Congratulations! After running the mint.js script with Hardhat using npx hardhat run scripts/mint.js --network NETWORK_NAME, you should now have minted the first music NFT in your collection! To add more NFTs, simply follow the process to create a new JSON file with different parameters and rerun the relevant functions, making sure to select the appropriate JSON file for the metadata variable in the mint.js function.

3.4: View your NFTs on MetaMask and OpenSea

If you’ve managed to complete the previous steps, this one should be quite simple. Begin by opening your MetaMask wallet or downloading it if you haven’t already. Log in and choose the Sepolia network at the top. Click the icon in the top right corner (not the MetaMask logo) and select Import Account. Opt for Private Key, as that’s how you initially set up your address, and paste it into the designated field. Afterward, head to the NFTs tab and select Import NFTs at the bottom. Paste your music NFT contract’s address into the first field, and the token ID in the next. If it’s your first mint the token ID will be 0. Finish the process by clicking Add, and there you have it—your music NFT is now visible in MetaMask!

Figure 2: Music NFT on MetaMask; Source:

Etherscan Unfortunately, MetaMask does not permit you to play the audio associated with your music NFT. To accomplish this, visit OpenSea, specifically the Sepolia Testnet version found here. Use MetaMask to log in, and once successful, hover over your avatar and click Profile. You should see your music NFT; click on it to reveal its details. If the featured image only shows a small preview, click on it once more and then a third time to open it in full screen, so your tune starts playing.

Figure 3: Music NFT on OpenSea; Source:

OpenSea Goerli

Access the tutorial repo

To make it even easier for you to follow and implement the concepts discussed in this tutorial, we have prepared a comprehensive code repository for your convenience. The repo contains all the necessary files, code snippets, and resources used throughout the tutorial. You can access the full tutorial code at its dedicated GitHub repo here. Feel free to download or clone the repository, and use it as a reference while working through the tutorial. This will help you save time and ensure that you have a complete understanding of the concepts presented.

Bringing it all together

With all of this taken care of, you have successfully dipped your feet and managed to explore the fascinating world of minting music NFTs. And thanks to this, you now have established a step-by-step process on how to create, deploy, and manage your very own digital music collectibles. By leveraging blockchain technology, artists and collectors like yourself can take full advantage of this new avenue for monetization, creative expression, and secure ownership. As you embark on your music NFT journey, remember that the possibilities are endless. Experiment with different parameters and smart contract functionalities to create NFTs that not only represent your unique artistic vision but also offer value to your audience. Whether you’re an established musician or an emerging talent, music NFTs can open doors to new opportunities and reshape the way you engage with and appreciate the art of sound. So go ahead, take the leap, and begin minting your very own music NFTs. Share your creations with the world, and witness the transformative power of this cutting-edge technology in the ever-evolving music industry. Happy minting!

About the author

Petar Stoykov

Senior Copywriter @ Chainstack Writes on Ethereum, NFTs, and underlying technology I BUIDL tutorials insightful so your dev experience can be delightful.

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​Main article

​How to mint a music NFT?

​Step 1: Get started with the basics

​1.1: Obtain a node endpoint

​1.2: Install core dependencies

​1.3: Securely store your secrets

​1.4: Create a new wallet and fund it

​1.5: Verify your wallet balance

​Step 2: Prepare and deploy the smart contract

​2.1: Draft an NFT smart contract

​2.2: Compile the minter smart contract

​ABI an BIN

​About __dirname

​2.3: Deploy your smart contract

​Step 3: Pin the metadata and mint your NFTs

​3.1: Getting started with Chainstack IPFS Storage

​3.2: Pin your NFT media with Chainstack IPFS Storage

​If the script returns Error during NFT pinning: Request failed with status code 400 as response.

​3.3: Create the script for minting

​3.4: View your NFTs on MetaMask and OpenSea

​Access the tutorial repo

​Bringing it all together

​About the author

Petar Stoykov

Main article

How to mint a music NFT?

Step 1: Get started with the basics

1.1: Obtain a node endpoint

1.2: Install core dependencies

1.3: Securely store your secrets

1.4: Create a new wallet and fund it

1.5: Verify your wallet balance

Step 2: Prepare and deploy the smart contract

2.1: Draft an NFT smart contract

2.2: Compile the minter smart contract

ABI an BIN

About `__dirname`

2.3: Deploy your smart contract

Step 3: Pin the metadata and mint your NFTs

3.1: Getting started with Chainstack IPFS Storage

3.2: Pin your NFT media with Chainstack IPFS Storage

If the script returns Error during NFT pinning: Request failed with status code 400 as response.

3.3: Create the script for minting

3.4: View your NFTs on MetaMask and OpenSea

Access the tutorial repo

Bringing it all together

About the author