ERC-721 and ERC-1155 are the two Ethereum token standards that make NFTs work. ERC-721 was proposed in January 2018 by William Entriken, Dieter Shirley, Jacob Evans and Nastassia Sachs, and it gives every token a unique ID tied to one owner, which is why it became the default standard for one-of-one art and PFP collections like CryptoPunks and Bored Ape Yacht Club. ERC-1155 followed in mid-2018, created by Enjin’s Witek Radomski and Andrew Cooke, and it lets a single smart contract manage many token types at once, fungible and non-fungible, and move several of them in one transaction through a batch transfer function. The practical difference for a buyer: ERC-721 fits unique collectibles where each piece needs its own identity, while ERC-1155 fits games and large multi-item drops where efficiency and bundled transfers matter more than one-off uniqueness. Most wallets and marketplaces support both, so you rarely need to check the standard before buying, but knowing it explains a lot about how a collection behaves.
When people talk about “the NFT standard,” they usually mean ERC-721. It’s the one that got adopted first and the one most profile-picture and art collections still use. But it’s not the only standard, and the second one, ERC-1155, exists specifically to fix problems the first one never solved. If you’ve noticed that some game items or large editions behave differently from a one-of-one NFT when you mint or transfer them, the token standard underneath is usually why. If you’re still working out what an NFT actually is before getting into the technical differences between standards, it helps to start there first.
What ERC-721 actually does
ERC-721 is an interface that a smart contract implements so that each token it issues has a unique tokenId and a single recorded owner, tracked through functions like ownerOf and events like Transfer and Approval (ethereum.org). Because every token ID is distinct and non-interchangeable, two ERC-721 tokens from the same contract are never equivalent the way two units of a currency are. That’s the literal meaning of “non-fungible”: token #42 and token #43 can look similar, but they are separate, individually owned assets with separate histories.
This design is well suited to things where uniqueness is the entire point: a single piece of generative art, a 1-of-1 photograph, a membership pass tied to one wallet, a specific plot of virtual land. The standard also supports an optional “Enumerable” extension that lets a contract or marketplace list every token a wallet owns, which is part of why collection pages on marketplaces can show you a full gallery of what you hold.
The tradeoff is that ERC-721 contracts handle one token at a time. If you want to transfer, approve, or mint ten tokens, that’s ten separate operations under the hood, even if they’re wrapped into a single user-facing transaction by the front end. For a 10,000-piece PFP collection sold one at a time, that’s rarely a problem. For a game that needs to hand a player fifty crafting items in a single action, it becomes expensive and clunky.
What ERC-1155 added and why it exists
ERC-1155 was proposed by Enjin’s Witek Radomski and Andrew Cooke in 2018 as a multi-token standard, meaning a single deployed contract can issue and manage any mix of fungible tokens, non-fungible tokens, and semi-fungible tokens (like 500 identical copies of one game sword) together (ethereum.org). Enjin built it to solve a specific problem it ran into with its own game economy: deploying a separate ERC-721 or ERC-20 contract for every single item type in a game is wasteful, both in deployment cost and in ongoing gas fees for players.
Batch transfers and gas efficiency
The core addition is the safeBatchTransferFrom function, which takes an array of token IDs and an array of amounts and moves all of them in one on-chain call instead of one call per token. A companion function, balanceOfBatch, lets an application check a wallet’s balance across many token types in a single query rather than looping through separate calls. For a game studio minting a loot drop with a dozen item types, or a project running a large multi-tier edition sale, that batching can mean real gas savings compared to doing the same job with separate ERC-721 transactions.
This is also why ERC-1155 is the more common choice for large-edition art drops (where hundreds of buyers mint the same image) and for blockchain games with inventories full of different item types, while it’s less common for art projects where every single piece is meant to be unique and separately valued.
Key differences at a glance
ERC-721 gives every token its own ID and owner, while ERC-1155 can represent both unique tokens and large stacks of identical ones under IDs that behave more like a shared pool. ERC-1155’s batch functions move multiple tokens in one transaction, where ERC-721 processes transfers individually. In practice, ERC-721 dominates 1-of-1 art, PFP collections, and membership NFTs, and ERC-1155 is more common in games, large editions, and ticketing systems that need many copies of the same item. Both standards are supported by every major marketplace and by wallets like MetaMask, so you can buy, hold, and resell either type without special setup.
The two standards also differ in how they typically handle metadata. Both point to off-chain or on-chain metadata describing the image, name, and traits, but ERC-1155 is more often paired with a single shared metadata URI pattern across a batch of similar items, while ERC-721 collections more commonly assign distinct metadata per token. For more on how that metadata is stored and why it matters for what you actually own, see our guide on on-chain vs. off-chain NFT metadata.
Which standard powers the NFTs you already own
If you’ve bought a single piece from a generative art collection, a profile picture NFT, or a 1-of-1 artwork, it’s almost certainly ERC-721. If you’ve picked up an item in a blockchain game, claimed a POAP-style event badge, or minted into a large open edition where thousands of people got an identical copy, there’s a good chance it’s ERC-1155. You can check which standard a specific NFT uses by looking at its contract on a block explorer like Etherscan, where the contract’s interface and function list will show whether it implements the ERC-721 or ERC-1155 interface. Most marketplace listing pages also note the token standard somewhere in the item details or contract info section.
Does the standard affect you as a buyer or collector?
For most buyers, day to day, the practical difference is small. Wallets, marketplaces, and explorers all support both standards natively, so you can buy, hold, and list either type without any extra steps. If you’re minting your first NFT, you generally don’t choose the standard yourself; the project’s contract already decided that before the mint went live.
Where it does matter is in a few specific situations. If a project markets itself as “1-of-1” or strictly limited, it’s worth confirming it’s actually using ERC-721 with distinct token IDs and metadata, not an ERC-1155 contract minting unlimited copies under a shared ID. If you’re buying multiple items from the same drop, an ERC-1155-based project may let you batch the purchase into fewer, cheaper transactions than an equivalent ERC-721 collection would. If you’re buying an item meant to be used inside a specific game or app, it helps to check which standard that ecosystem expects, since some in-game systems are built only around ERC-1155 inventories. And rarity-ranking tools and some analytics sites are built primarily around ERC-721’s one-token-one-owner model, so ERC-1155 items with shared IDs may show up differently or not at all on those tools.
Neither standard is inherently “better” than the other. They solve different problems, and most of the time the project’s own choice of standard already matches what it’s trying to do: unique art and collectibles lean ERC-721, while games, large editions, and multi-item systems lean ERC-1155. Knowing which one you’re dealing with mostly helps you understand why a collection behaves the way it does, rather than changing anything about how you buy or hold it.