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

Basic ERC-721 NFT Contract

📖 Scenario: You want to create a simple NFT (Non-Fungible Token) contract on Ethereum. NFTs are unique digital items like collectibles or art. ERC-721 is the standard interface for NFTs.In this project, you will build a basic ERC-721 contract that can mint unique tokens and keep track of their owners.

🎯 Goal: Build a simple ERC-721 contract named SimpleNFT that allows minting unique tokens with IDs and stores ownership information.

📋 What You'll Learn

Create a contract named SimpleNFT that inherits from OpenZeppelin's ERC721.

Add a constructor that sets the token name to SimpleNFT and symbol to SNFT.

Create a public function mintNFT that takes an address recipient and a uint256 tokenId and mints a new token to the recipient.

Use OpenZeppelin's ERC721 implementation for standard NFT behavior.

💡 Why This Matters

🌍 Real World

NFTs are used for digital art, collectibles, gaming items, and more. This contract is a simple foundation for creating unique digital assets on Ethereum.

💼 Career

Understanding ERC-721 is essential for blockchain developers working on NFT projects, marketplaces, or decentralized applications involving unique tokens.

1

Set up the contract and import ERC721

Write the Solidity code to declare a contract named SimpleNFT that imports OpenZeppelin's ERC721 contract from @openzeppelin/contracts/token/ERC721/ERC721.sol.

Blockchain / Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

// Import ERC721 from OpenZeppelin
// Your code here

Need a hint?

Use import "@openzeppelin/contracts/token/ERC721/ERC721.sol"; and declare contract SimpleNFT is ERC721.

2

Add constructor to set name and symbol

Add a constructor to SimpleNFT that calls the ERC721 constructor with the name "SimpleNFT" and symbol "SNFT".

Blockchain / Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

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

contract SimpleNFT is ERC721 {
    // Add constructor here
    // Your code here
}

Need a hint?

Use constructor() ERC721("SimpleNFT", "SNFT") {} to set the token name and symbol.

3

Create mintNFT function to mint tokens

Add a public function named mintNFT that takes address recipient and uint256 tokenId as parameters and calls _mint(recipient, tokenId) to mint the token.

Blockchain / Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

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

contract SimpleNFT is ERC721 {
    constructor() ERC721("SimpleNFT", "SNFT") {}

    // Add mintNFT function here
    // Your code here
}

Need a hint?

Define function mintNFT(address recipient, uint256 tokenId) public and call _mint(recipient, tokenId); inside it.

4

Test minting by calling mintNFT

Write a comment line showing how to call mintNFT to mint token ID 1 to address 0x1234567890123456789012345678901234567890.

Blockchain / Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

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

contract SimpleNFT is ERC721 {
    constructor() ERC721("SimpleNFT", "SNFT") {}

    function mintNFT(address recipient, uint256 tokenId) public {
        _mint(recipient, tokenId);
    }
}

// Call mintNFT to mint token ID 1 to address 0x1234567890123456789012345678901234567890
// Your code here

Need a hint?

Write a comment showing the call: simpleNFT.mintNFT(0x1234567890123456789012345678901234567890, 1);