Smart Contract Standards: ERC-721 vs ERC-1155

When people talk about NFTs, they usually focus on the art, the price tag, or the marketplace. Very few stop to ask what is actually running underneath, what code makes a digital file provably owned, uniquely identified, and transferable without a middleman. The answer, in most cases, comes down to two Ethereum token standards: ERC-721 and ERC-1155.

These two smart contract standards are the foundation of nearly every NFT project you have heard of, from CryptoKitties to Bored Ape Yacht Club to blockchain games like Axie Infinity. Yet most people cannot explain what they actually do differently, or why choosing one over the other matters so much when building an NFT project.

This blog breaks it all down in plain language. No jargon overload. No unnecessary filler. Just a clear look at what each standard is, how it works, where it falls short, and which one fits which type of project.

What Is a Smart Contract Standard on Ethereum?

Before diving into the comparison, it helps to understand what a smart contract standard actually means. On Ethereum, a standard is a set of agreed-upon rules that developers follow when writing code for their tokens. These rules are introduced through a process called Ethereum Improvement Proposals, or EIPs. Once approved by the developer community, they become ERCs, which stand for Ethereum Request for Comments. Every experienced NFT marketplace development company follows these standards to ensure NFTs work smoothly across wallets, marketplaces, and blockchain applications.

The reason standards matter is interoperability. When your NFT follows the ERC-721 standard, any wallet, marketplace, or application built to work with ERC-721 tokens can read, display, and transfer your NFT without needing custom code. Without these shared rules, the blockchain ecosystem would be a mess of incompatible systems.

So when someone says “ERC-721 NFT” or “ERC-1155 token,” they are describing the technical rulebook that the smart contract behind that token follows.

What Is ERC-721? The Standard That Started It All

ERC-721 is the first Ethereum standard specifically built for non-fungible tokens. It was formally published in January 2018 by William Entriken, Dieter Shirley, Jacob Evans, and Nastassia Sachs. But the story behind it starts a bit earlier.

In September 2017, Dieter Shirley introduced the idea as EIP-721 on Ethereum’s GitHub. Around that same time, the blockchain game CryptoKitties launched using an early version of this standard. The game became so popular that by December 2017, it was responsible for serious congestion on the Ethereum network, slowing down transaction speeds across the board. That kind of attention put ERC-721 on the map. By June 2018, the Ethereum community reached a strong consensus and accepted ERC-721 as a finalized standard.

1. How ERC-721 Works

The core idea of ERC-721 is simple: one token, one owner, one unique identity. Every token created under this standard gets a numerical identifier called a TokenID. The combination of the smart contract address and the TokenID is what makes each NFT globally unique. No two tokens from the same contract can share a TokenID, and no two different contracts can produce the same contract-address-plus-TokenID pair.

This is how an entire collection of NFTs can live in one smart contract. Think of a collection of 10,000 digital artworks. All of them share the same contract, but each piece has its own TokenID from 1 to 10,000. That is the backbone of projects like Bored Ape Yacht Club.

2. Key Features of ERC-721

• Uniqueness of every token: Each token is a one-of-a-kind asset. It cannot be swapped on a like-for-like basis with another token from the same contract.
• On-chain ownership tracking: Every transfer is recorded on the blockchain permanently. The ownerOf function lets anyone check who holds a specific TokenID at any point in time.
• Metadata support: Developers can attach a URI (Uniform Resource Identifier) to each token, pointing to its image, name, description, and other traits stored on or off the blockchain.
• Transfer and approval functions: The standard defines safe transfer functions and operator approval systems, allowing marketplaces like OpenSea to list and sell NFTs on a holder’s behalf.
• Wide wallet and marketplace support: Because ERC-721 was the first and remains one of the most recognized standards, it is supported by virtually every Ethereum-compatible wallet and NFT marketplace.

3. Where ERC-721 Falls Short

The most talked-about limitation of ERC-721 is its inability to handle batch transfers. If you want to send 20 NFTs to someone, ERC-721 requires 20 separate transactions, each paying its own gas fee. As the Ethereum network gets busier, those fees can add up to significant amounts. For platforms dealing with thousands of token transfers per day, this creates a real cost problem.

Another limitation is that ERC-721 can only represent non-fungible tokens. It cannot create a fungible token (like a coin or a currency) or a semi-fungible token (like an event ticket that is identical to others until it gets redeemed). This makes it a less flexible choice for projects that need to manage multiple types of assets within one system.

What Is ERC-1155? The Multi-Token Standard

ERC-1155 was created by Witek Radomski and the Enjin team. Enjin had been building a blockchain gaming toolkit internally since 2017 under the name “Monolithic Token Contract” and quickly realized that neither ERC-20 nor ERC-721 was flexible enough for what they needed: a system that could handle hundreds of different in-game item types without deploying hundreds of separate contracts.

Radomski published the first version of ERC-1155 on Ethereum’s GitHub on June 17, 2018. After more than 50 revisions and 400 community comments, the standard reached Final status in June 2019 and became an official part of the Ethereum ecosystem.

1. How ERC-1155 Works

The key difference from ERC-721 is that a single ERC-1155 smart contract can manage an unlimited number of token types. Each token type is identified by its own ID, but unlike ERC-721, where each ID represents exactly one unique token, in ERC-1155, each ID can represent a configurable token type with its own supply. Set the supply to 1, and you have an NFT. Set it to 1,000,000, and you have a fungible token. Set it to 50, and you have a semi-fungible token.

This is why ERC-1155 is called the Multi Token Standard. One contract, any combination of token types. A blockchain game could use one ERC-1155 contract to manage its gold coins (fungible), its legendary swords (non-fungible), and its consumable health potions (semi-fungible), all at once, without deploying three separate contracts.

2. Key Features of ERC-1155

• Batch transfers: The safeBatchTransferFrom function lets you move multiple token types in a single transaction. Instead of paying gas for each individual transfer, you pay for one grouped action.
• Mixed token types in one contract: Fungible, non-fungible, and semi-fungible tokens can all live under one contract address, removing the need for multiple deployments.
• Gas savings of up to 90 percent: Using Balance Packing, developers can store 16 lower-resolution token balances in a single ID, achieving gas savings of 80 to 90 percent compared to regular ERC-20 or ERC-721 transfers.
• Enhanced transfer safety: Built-in hooks and rules ensure that tokens sent to contracts that cannot handle them are reverted, preventing the kind of permanent token loss that can happen with less careful implementations.
• Atomic swaps: ERC-1155 enables atomic swaps of multiple token types in just two steps, making trading and escrow systems much easier to build without needing a wrapper contract.
• Flexible metadata: While ERC-721 gives each token its own unique metadata URI, ERC-1155 uses a shared URI pattern with placeholder support, allowing each token type to have distinct metadata while reducing storage overhead.

ERC-721 vs ERC-1155

Feature	ERC-721	ERC-1155
Year Finalized	June 2018	June 2019
Token Types Supported	Non-fungible only	Fungible, Non-fungible, Semi-fungible
Contracts per Token Type	One contract per collection	One contract for unlimited token types
Batch Transfers	Not supported natively	Supported via safeBatchTransferFrom
Gas Cost	Higher (one transaction per token)	Up to 90% lower with batch operations
Metadata Handling	Unique URI per token	Shared URI with per-type placeholders
Semi-fungible Tokens	Not supported	Natively supported
Atomic Swaps	Requires wrapper contract	Built-in support
Best Use Case	One-of-a-kind digital art and collectibles	Gaming, mixed-asset platforms, DeFi
Wallet and Marketplace Support	Very broad (oldest standard)	Broad and growing rapidly

Differences Between ERC-721 and ERC-1155

Looking at both standards side by side makes the differences clear, but it helps to understand what those differences mean in practice, not just in theory.

1. One Contract vs. Many Contracts

With ERC-20 and ERC-721, every new token type requires a fresh smart contract deployment. A blockchain game with 10 in-game currencies and 40 types of unique items would need 50 separate contracts. Each deployment costs ETH and adds complexity for wallets and marketplaces trying to track ownership across all of them. ERC-1155 solves this by letting a single contract manage all of those token types at once. This is not just convenient; it actively reduces the amount of redundant code sitting on the Ethereum blockchain.

2. Gas Fees

Gas is what you pay Ethereum validators for processing your transaction. Every time you mint, transfer, or burn an NFT, you pay gas. With ERC-721, if you want to send someone a bundle of 10 different NFTs, you trigger 10 separate transactions. At peak Ethereum congestion, this can become surprisingly expensive.

ERC-1155’s batch transfer system changes this dramatically. One transaction handles the movement of multiple token types. Using the Balance Packing technique, developers have demonstrated gas savings of 80 to 90 percent compared to equivalent ERC-721 operations. Phillippe Castonguay of Horizon Games also demonstrated that ERC-1155 could achieve a transfer speed of over 155 assets per second, a number ERC-721 simply cannot match on its own.

3. Semi-Fungible Tokens

Semi-fungible tokens (SFTs) are one of the more interesting concepts ERC-1155 introduces. A semi-fungible token starts out behaving like a fungible token (all copies are equal and interchangeable), but it can become non-fungible after a specific event. The clearest example is an event ticket. Before the concert, every ticket in section A, row 5 is identical and interchangeable with any other. After the concert, that same ticket becomes a unique record of a specific attendance, which is non-fungible. ERC-1155 supports this lifecycle natively. ERC-721 cannot do this without significant workarounds.

4. Token Security and Risk Profiles

Because ERC-721 spreads its tokens across many individual contracts, a vulnerability in any one of those contracts can affect the tokens stored in it. ERC-1155’s single-contract approach concentrates risk differently. It is easier to audit one well-built contract than 50 separate ones, and ERC-1155’s built-in transfer hooks actively prevent tokens from getting stuck in contracts that do not know how to handle them, a known risk in earlier standards.

Use Cases: Where Each Standard Makes the Most Sense

Use Case	Best Standard	Why
One-of-a-kind Digital Art	ERC-721	Each token’s uniqueness is central to its value; the 1:1 model is ideal
NFT Collectible Collections	ERC-721	Proven model for PFP projects, widely supported by all major marketplaces
Blockchain Gaming (Items + Currency)	ERC-1155	Manages fungible currencies and unique items together in one contract
Event Ticketing	ERC-1155	Semi-fungible support lets tickets be interchangeable before use, unique after
DeFi Platforms (Multi-asset)	ERC-1155	Batch operations reduce gas costs for frequent multi-token activity
Virtual Real Estate (Single Plots)	ERC-721	Each land plot is unique; Decentraland uses ERC-721 LAND tokens
Brand NFT Promotions (Physical + Digital)	ERC-1155	Adidas used ERC-1155 to bundle physical and digital merch in one contract
Music or Art Editions (Limited Copies)	ERC-1155	Supports editions of the same artwork (e.g. 100 copies) within one token type

Which Standard Should You Choose?

The answer depends entirely on what you are building. There is no universally correct choice between ERC-721 and ERC-1155. Both serve specific purposes, and both have a strong place in the NFT ecosystem.

1. Choose ERC-721 if:

• Your entire project revolves around one-of-a-kind assets where each token must be completely distinct from all others.
• You are creating a digital art collection, PFP project, or collectible set where the uniqueness of each token drives its value.
• Maximum marketplace compatibility matters, since ERC-721 enjoys broader recognition across older wallets and platforms.
• You do not need to manage multiple token types, and the simpler architecture suits your project scope.

2. Choose ERC-1155 if:

• You are building a blockchain game that needs in-game currencies, unique items, and consumables all in one place.
• Your project needs to handle a high volume of token transfers, and gas costs are a real concern.
• You want to create limited edition NFTs (like 50 copies of the same artwork) rather than strictly one-of-a-kind pieces.
• Your use case involves semi-fungible tokens, such as event tickets, loyalty points, or redeemable vouchers.
• You need to combine digital and physical asset redemption within a single contract, as Adidas demonstrated.

It is also worth noting that the two standards are not mutually exclusive. Some platforms use ERC-721 for their flagship rare collectibles and ERC-1155 for their in-platform currencies and consumables, getting the best of both systems in one project.

Common Misunderstandings About These Standards

1. “ERC-1155 is just an upgraded ERC-721”

This is not quite right. ERC-1155 is not a direct upgrade that makes ERC-721 obsolete. It is a different tool with different strengths. ERC-721 remains the better choice for strict 1-of-1 assets. ERC-1155 is better for mixed-asset, high-volume, or multi-type environments. Calling one an upgrade of the other misses the point that they were designed for different needs.

2. “ERC-1155 tokens cannot be true NFTs.”

This is false. When the supply of a specific token ID in an ERC-1155 contract is set to exactly 1, it functions as a true NFT, no different in uniqueness from an ERC-721 token. The Ethereum Foundation’s own documentation confirms this: “When the supply is just one, the token is essentially a non-fungible token.”

3. “The standard your NFT uses does not matter to buyers.”

Most NFT buyers are not aware of the standard their tokens use, and that is fine from a user perspective. But it matters enormously to developers and platform builders. The standard determines gas costs, functionality, and the complexity of building features on top of the token. Choosing the wrong standard for your project can mean higher operating costs, limited flexibility, or expensive contract rewrites later.

Conclusion

ERC-721 and ERC-1155 are both important parts of how the NFT world works on Ethereum. ERC-721 gave digital ownership a clear and verifiable meaning for the first time, and it remains the go-to standard for projects where every token’s uniqueness is the entire point. ERC-1155 came along to handle the limitations that became obvious once developers started building more complex systems, bringing batch transfers, multi-token support, and dramatic gas savings to the table.

Neither standard is going away. Both are used actively today, often within the same ecosystem. What changes is the context. A photographer selling 1-of-1 digital prints needs ERC-721. A gaming studio managing thousands of items, currencies, and collectibles needs ERC-1155. A concert venue running NFT ticketing needs ERC-1155 for the semi-fungible lifecycle that those tickets require.

The decision comes down to understanding your project, its assets, its volume, and its users. With that clarity, choosing between ERC-721 and ERC-1155 becomes less of a technical puzzle and more of a straightforward engineering decision. Build on the standard that fits what you are actually making, not the one with the most buzz.