🎨 What is an NFT ?

If ERC-20 tokens represent fungible assets like money or points, NFTs are their unique, one-of-a-kind cousins. They’re the digital collectibles, membership passes, and proof-of-ownership certificates that power much of Web3 today.

Let’s unpack what that actually means 👇

🧩 NFT in Simple Terms

NFT stands for Non-Fungible Token.

• Non-fungible means it can’t be replaced by another identical item.

  • A dollar bill? Fungible — any other $1 bill is the same.

  • A rare baseball card? Non-fungible — it’s unique.

• Token means it’s a digital asset on a blockchain, just like an ERC-20 token.

Put together, an NFT is a unique digital certificate stored on the blockchain that proves you own something — digital or even physical.

🎟️ What NFTs Can Represent

NFTs are like digital wrappers that can point to almost anything:

• 🖼️ Digital art (like the ones sold on OpenSea or Foundation)

• 🎧 Music, videos, or animations

• 🕹️ In-game items (skins, weapons, land plots)

• 🎟️ Tickets or membership passes

• 🏠 Real-world assets, like deeds or certificates

• 🧾 Receipts or credentials (like a diploma stored on-chain)

Essentially, NFTs turn ownership into code. Instead of trusting a database or platform, the blockchain becomes your proof of authenticity.

⚙️ The ERC-721 Standard

Most NFTs on Ethereum follow the ERC-721 standard — introduced after ERC-20. While ERC-20 focuses on interchangeable tokens, ERC-721 focuses on unique ones.

Core ERC-721 Functions

Function	Purpose
ownerOf(tokenId)	Returns who owns a specific NFT
balanceOf(address)	Shows how many NFTs an address holds
transferFrom(address, address, tokenId)	Moves ownership of an NFT
tokenURI(tokenId)	Returns metadata (e.g., image, name, traits)

The tokenURI is what links your NFT to off-chain data — like an image stored on IPFS or Arweave.

🧠 Example in Code

Here’s a tiny NFT contract using OpenZeppelin:

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

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

contract CheeseArtNFT is ERC721 {
    uint256 public nextId;

    constructor() ERC721("Cheese Art", "CHEESEART") {}

    function mint() external {
        _safeMint(msg.sender, nextId);
        nextId++;
    }
}

Each time you call mint(), it creates a unique token with a new tokenId. No two CheeseArt NFTs are the same — even if they look alike 🧀🎨.

🌐 Why NFTs Matter

NFTs gave us a way to own and trade digital assets without needing permission from centralized platforms.

They enable:

• Digital property rights → verifiable ownership on-chain

• Creator royalties → artists earn from secondary sales

• Interoperability → same NFT can be used across apps or games

• Identity and membership → NFTs as access keys to communities or events

It’s less about “JPEGs on a blockchain” and more about programmable ownership.

💡 ERC-1155: The Hybrid Standard

There’s also ERC-1155, a newer, more flexible standard that supports both fungible and non-fungible tokens in one contract. It’s often used for gaming and multi-asset collections — think bundles of weapons, tickets, or currencies all managed together.

🏁 Final Thoughts

NFTs are the evolution of digital ownership. They make items verifiable, portable, and programmable, unlocking a world of new possibilities — from art and gaming to identity and beyond.

So next time someone says, “Why would anyone buy a JPEG?” You can tell them: it’s not just a JPEG — it’s a tokenized piece of digital history.