ERC-721 NFT standard in Blockchain / Solidity - Mini Project: Build & Apply

Create a Simple ERC-721 NFT Contract

📖 Scenario: You want to create your own unique digital collectibles on the blockchain. These collectibles are called NFTs (Non-Fungible Tokens). The ERC-721 standard is a popular way to make NFTs that are one-of-a-kind.In this project, you will build a simple ERC-721 contract that lets you create and track unique tokens.

🎯 Goal: Build a basic ERC-721 smart contract that can mint unique NFTs with token IDs and names.

📋 What You'll Learn

Create a contract that inherits from OpenZeppelin's ERC721

Set the NFT collection name and symbol

Add a function to mint new NFTs with unique token IDs

Store and retrieve token metadata (like a name)

💡 Why This Matters

🌍 Real World

NFTs are used for digital art, collectibles, gaming items, and more. This project shows how to create unique tokens that represent ownership of digital items.

💼 Career

Understanding ERC-721 is essential for blockchain developers working on NFT marketplaces, games, or digital asset platforms.

1

Set up the ERC-721 contract

Write a Solidity contract named MyNFT that inherits from ERC721. Import @openzeppelin/contracts/token/ERC721/ERC721.sol. In the constructor, set the token name to "MyNFTCollection" and the symbol to "MNFT".

Blockchain / Solidity

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

// Your code here

Need a hint?

Use import to bring in the ERC721 contract. Then create MyNFT that extends ERC721. The constructor calls the parent constructor with the name and symbol.

2

Add a counter for token IDs

Add a private uint256 variable called _tokenIdCounter initialized to 0 to keep track of the next token ID to mint.

Blockchain / Solidity

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

contract MyNFT is ERC721 {
    uint256 private _tokenIdCounter = 0;
    constructor() ERC721("MyNFTCollection", "MNFT") {}
    // Your code here
}

Need a hint?

Declare a private variable _tokenIdCounter of type uint256 and set it to zero.

3

Create a minting function

Add a public function mintNFT that takes an address to and a string memory tokenName. Inside, increment _tokenIdCounter, mint a new token with the new ID to to, and store the tokenName in a mapping called _tokenNames keyed by token ID.

Blockchain / Solidity

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

contract MyNFT is ERC721 {
    uint256 private _tokenIdCounter = 0;
    mapping(uint256 => string) private _tokenNames;
    constructor() ERC721("MyNFTCollection", "MNFT") {}

    // Your code here
}

Need a hint?

Inside mintNFT, increase _tokenIdCounter, mint the token to to, and save the name in _tokenNames.

4

Add a function to get token name and test minting

Add a public view function getTokenName that takes uint256 tokenId and returns the stored token name from _tokenNames. Then, mint an NFT to your own address with the name "FirstNFT" and print the token name for token ID 1.

Blockchain / Solidity

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

contract MyNFT is ERC721 {
    uint256 private _tokenIdCounter = 0;
    mapping(uint256 => string) private _tokenNames;
    constructor() ERC721("MyNFTCollection", "MNFT") {}

    function mintNFT(address to, string memory tokenName) public {
        _tokenIdCounter++;
        uint256 newTokenId = _tokenIdCounter;
        _mint(to, newTokenId);
        _tokenNames[newTokenId] = tokenName;
    }

    // Your code here
}

Need a hint?

Create getTokenName to return the name for a token ID. Minting and printing can be tested in your development environment.