NFT Token Standards Explained: ERC-721, ERC-1155, and What Matters in 2025

When you buy an NFT, you’re not just buying a picture—you’re buying a piece of code that follows a NFT token standard, a set of rules that tells blockchains how to recognize, transfer, and display digital assets. Also known as smart contract standards, these rules make sure your NFT works across wallets, marketplaces, and games without breaking. Without them, every NFT would be a lonely file with no way to prove ownership or move between platforms.

Two standards dominate the space: ERC-721, the original NFT standard that gives each token a unique identity, perfect for collectibles like digital art or rare virtual items, and ERC-1155, a more flexible system that lets one contract handle multiple types of tokens—both unique and identical—making it ideal for games and bundles. ERC-721 is like owning one rare baseball card. ERC-1155 is like owning a pack of cards where some are rare, some are common, and they all live in the same wallet. Most modern NFT projects, especially in gaming and metaverses, use ERC-1155 because it’s cheaper, faster, and cuts down on bloated blockchain data.

These standards aren’t just technical details—they affect your money. If a project uses a non-standard or custom contract, you risk losing access to your NFT if a marketplace doesn’t support it. That’s why platforms like OpenSea and Blur only list NFTs built on widely accepted standards. Even worse, fake NFTs often copy the look of real ones but skip the standard entirely, making them impossible to sell or verify. You can’t trust a token just because it looks cool.

Behind every NFT you trade, interact with, or collect, there’s a standard doing the heavy lifting. Whether you’re buying a profile picture, a virtual land plot, or a gaming item, knowing if it’s ERC-721 or ERC-1155 helps you avoid scams, understand fees, and spot real utility. Below, you’ll find real-world examples of how these standards work—or fail—in practice, from failed launches to hidden risks in popular projects. No fluff. Just what you need to know before you click buy.