ERC-721

27min

Overview
Pros
Well-established standard with broad support from Ethereum wallets and exchanges.
Allows for the creation of unique, non-fungible tokens.
Suitable for creating digital collectibles and representing unique assets.
Cons
Only allows for the creation of a single type of token.
Inefficient for creating multiple types of NFTs.
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🏁 Prerequisites
﻿Using Hardhat﻿﻿
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Tutorial
1. Write your ERC-721 contract
We'll use a contract based on the OpenZeppelin library’s [ERC-721 implementation]().
a) First, install the Open Zeppelin library in order to inherit its classes:
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Shell
npm install @openzeppelin/contracts
npm install @openzeppelin/contracts
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b) Next, create a file named NFT.sol under the contracts folder.
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c) Lastly, add the following smart contract to NFT.sol file. 
Note that we have named our contract NFT, this can be any name. The name will be important in the next step.
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JS
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

contract NFT is ERC721 {
    constructor() ERC721("MyERC721", "M721") {}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

contract NFT is ERC721 {
    constructor() ERC721("MyERC721", "M721") {}
}
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2. Install Hardhat Deploy
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Shell
npm install -D hardhat-deploy
npm install -D hardhat-deploy
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3. Install an Ethereum library
In this example, we will use Ether.js﻿
Shell
npm install --save-dev @nomiclabs/hardhat-ethers ethers@^5.0.0
npm install --save-dev @nomiclabs/hardhat-ethers ethers@^5.0.0
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4. Set environment variables with dotenv﻿
 Install dotenv
Shell
npm install --save dotenv
npm install --save dotenv
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Keep Your Private Keys Secret

Private keys must be kept secret and not committed to any code repository. In the example of this tutorial, the .env file should be added to your .gitignore file and kept local.

For example, see MyCrypto's Protecting Yourself and Your Funds guide.﻿
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Create a .gitignore  file
A great example of a Solidity .gitignore file can be found here﻿
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Create an  .env file n your project's root folder, and set environment variables in the file as follows
﻿Intro to Infura﻿ 
﻿MetaMask Wallet Setup﻿﻿
PRIVATE_KEY = #The private key of the account you intend to use on the Palm network
INFURA_API_KEY = #Your Infura API key
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5. Edit hardhat.config.js with the following text:
You can add additional supported fields on the hardhat.config.js  file.
JS
require("dotenv").config()
require("@nomiclabs/hardhat-ethers")
require("hardhat-deploy")

const key = '';

module.exports = {
  solidity: "0.8.17",
  settings: {
    optimizer: {
      enabled: true,
      runs: 1000000,
    },
  },
  mocha: {
    timeout: 90000,
  },
  networks: {
    hardhat: {
      initialBaseFeePerGas: 0,
      blockGasLimit: 18800000,
    },
    palm_testnet: {
      url: `https://palm-testnet.infura.io/v3/${process.env.INFURA_API_KEY}`,
      accounts: [`0x` + process.env.PRIVATE_KEY],
      gasPrice: 1000,
      saveDeployments: true,
      deploy: ["scripts/"],
    },
    palm_mainnet: {
      url: `https://palm-mainnet.infura.io/v3/${process.env.INFURA_API_KEY}`,
      accounts: [`0x` + process.env.PRIVATE_KEY],
      gasPrice: 1000,
      saveDeployments: true,
      deploy: ["scripts/"],
    },
  },
  namedAccounts: {
    deployer: 0
  },
}
require("dotenv").config()
require("@nomiclabs/hardhat-ethers")
require("hardhat-deploy")

const key = '';

module.exports = {
  solidity: "0.8.17",
  settings: {
    optimizer: {
      enabled: true,
      runs: 1000000,
    },
  },
  mocha: {
    timeout: 90000,
  },
  networks: {
    hardhat: {
      initialBaseFeePerGas: 0,
      blockGasLimit: 18800000,
    },
    palm_testnet: {
      url: `https://palm-testnet.infura.io/v3/${process.env.INFURA_API_KEY}`,
      accounts: [`0x` + process.env.PRIVATE_KEY],
      gasPrice: 1000,
      saveDeployments: true,
      deploy: ["scripts/"],
    },
    palm_mainnet: {
      url: `https://palm-mainnet.infura.io/v3/${process.env.INFURA_API_KEY}`,
      accounts: [`0x` + process.env.PRIVATE_KEY],
      gasPrice: 1000,
      saveDeployments: true,
      deploy: ["scripts/"],
    },
  },
  namedAccounts: {
    deployer: 0
  },
}
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6. Compile your Contract
To make sure everything is working so far, let’s compile our contract:
Shell
Example Response
Downloading compiler 0.8.6
Compiled 13 Solidity files successfully
Downloading compiler 0.8.6
Compiled 13 Solidity files successfully
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7. Write a deploy script
a) Navigate to the scripts folder and create a new file called deploy_NFT.js
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b) Add the below code
JS
module.exports = async ({
    getNamedAccounts,
    deployments,
    getChainId,
    getUnnamedAccounts,
    }) => {
    const {deploy} = deployments;
    const {deployer} = await getNamedAccounts();

    console.log("Contract deployed to address:", deployer);

    // Deploy "NFT" if the contract was never deployed or if the code has changed since the last deployment
    await deploy('NFT', {
        from: deployer,
        gasLimit: 4000000,
        args: [],
        log: true,
    });
};
module.exports = async ({
    getNamedAccounts,
    deployments,
    getChainId,
    getUnnamedAccounts,
    }) => {
    const {deploy} = deployments;
    const {deployer} = await getNamedAccounts();

    console.log("Contract deployed to address:", deployer);

    // Deploy "NFT" if the contract was never deployed or if the code has changed since the last deployment
    await deploy('NFT', {
        from: deployer,
        gasLimit: 4000000,
        args: [],
        log: true,
    });
};
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8. Deploy to the target Palm network environment
Palm Testnet
Palm Mainnet
Example log
Contract deployed to address: 0xeC1AFf99d2C331B226A5731B9555Af924932d629
Contract deployed to address: 0xeC1AFf99d2C331B226A5731B9555Af924932d629
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﻿TLDR; How This is Working﻿
The task will execute the scripts in the scripts folder and saves the contract deployments to disk. Each deployment is saved into the deployments folder for the specific network.
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9. Look Up Your Deployment on the Palm Network Block Explorer
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Testnet
Mainnet
Explorer URL
﻿https://explorer.palm-uat.xyz﻿
﻿https://explorer.palm.io﻿
Paste your contract address into the search bar.
Get your contract address in 2 ways:
Console.log() output Contract deployed to address: contractNumber 
In deployments/palm_testnet/NFT.json or deployments/palm_mainnet/NFT.json where you will also find the ABI (Application Binary Interface) information.
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You will see something like this upon successful deployment 👇 
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10. Verify via Sourcify
Palm Testnet
Palm Mainnet
Example log
verifying NFT (0x776b8ea33195AA9166fF27C9965cCe7ae01B069F on chain 11297108109) ...
 => contract NFT is now verified
verifying NFT (0x776b8ea33195AA9166fF27C9965cCe7ae01B069F on chain 11297108109) ...
 => contract NFT is now verified
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﻿Using Sourcify﻿﻿
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Next Step 👉 Mint your NFT
Using the Smart Contract you just deployed you can now Mint NFTs with Hardhat﻿ 