Create Your NFT Smart Contract

Now that your NFT files are prepared, it's time to create the smart contract that will manage your NFT collection. We'll use OpenZeppelin, a trusted library for building secure smart contracts.

Why OpenZeppelin?

OpenZeppelin provides battle-tested, audited smart contract implementations that follow industry standards. Their Contract Wizard allows you to generate customized contracts without writing code from scratch, reducing the risk of security vulnerabilities.

Using the Contract Wizard

Step 1: Access the Wizard

Navigate to wizard.openzeppelin.com/#erc721

Step 2: Select ERC-721

Make sure the ERC-721 tab is selected. This will create a contract in the Solidity programming language specifically for non-fungible tokens.

Step 3: Configure Basic Settings

The wizard provides a template contract that you'll customize:

Name: Give your NFT collection a name (e.g., "Photography") Symbol: Choose a short symbol for your collection (e.g., "FOTO") Base URI: Paste the metadata folder URL you saved from Pinata

Example: https://gateway.pinata.cloud/ipfs/QmYdWxbiwsfsYcW1CYQPgYujAc9FMLPG3fgFcxFskbSsFa

Step 4: Add Minting Functionality

Check the following boxes to add essential features:

Mintable: Adds a safeMint function to create new NFTs Auto Increment Ids: Automatically assigns sequential token IDs

This will automatically check Ownable, which restricts the safeMint function to the contract owner.

Understanding the Generated Contract

Let's examine the key parts of your generated contract:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

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

contract Photography is ERC721, Ownable {
    uint256 private _nextTokenId;
    string private _baseTokenURI;

    constructor(address initialOwner)
        ERC721("Photography", "FOTO")
        Ownable(initialOwner)
    {
        _baseTokenURI = "https://gateway.pinata.cloud/ipfs/QmYdWxbiwsfsYcW1CYQPgYujAc9FMLPG3fgFcxFskbSsFa/";
    }

    function _baseURI() internal view override returns (string memory) {
        return _baseTokenURI;
    }

    function safeMint(address to) public onlyOwner {
        uint256 tokenId = _nextTokenId++;
        _safeMint(to, tokenId);
    }
}

Key Components

Inheritance: Your contract inherits from ERC721 (the standard) and Ownable (access control)

Constructor: Sets the collection name, symbol, and base URI when deployed

_baseURI(): Returns the base URI that will be combined with token IDs to fetch metadata

safeMint(): Creates new NFTs and assigns them sequential IDs

About the safeMint Function

The current safeMint function:

• Mints one NFT at a time
• Can mint to any address (not just the owner's)
• Charges no fee (except gas)
• Functions as an "airdrop" mechanism

This is perfect for:

• Personal collections
• Gifting NFTs
• Controlled distributions
• Testing your contract

For a public sale, you would modify this function to:

• Accept payment (e.g., payable with price checks)
• Remove the onlyOwner modifier
• Add supply limits
• Implement per-wallet minting limits

Next Steps

Your smart contract is now ready! Click Open in Remix at the top of the wizard to prepare for deployment.

In the next section, we'll deploy this contract to the Avalanche network and mint your first NFT.