If you have browsed NFTs on Base, you have already interacted with one of two token standards without necessarily noticing: ERC-721 or ERC-1155. Both let a smart contract represent ownership of digital items, and both show up in your wallet as NFTs. But the way they are built underneath is different, and that difference shapes things you actually experience, like gas costs, how a collection is minted, and how your wallet groups your items.
What ERC-721 does
ERC-721 was the first widely adopted NFT standard on Ethereum, and it still underlies most single edition art, profile picture collections, and domain name NFTs, including Basenames. The core idea is simple: each token has a unique ID, and that ID can only ever belong to one owner at a time. A single ERC-721 contract typically represents one collection, and every token inside it, however many there are, is treated as one of a kind, even if two items look identical to the eye.
Your wallet's balanceOf call for an ERC-721 contract tells you how many different token IDs you hold in that collection, not how many copies of any one item, because by design there is no such thing as a copy. If you want to move ten NFTs from the same collection, standard ERC-721 requires ten separate transfers, each with its own gas cost.
What ERC-1155 does
ERC-1155 is a newer standard, often called the multi-token standard, and it was designed to fix two specific limitations of ERC-721: inefficiency with large quantities of similar items, and the need for a new contract per collection type.
A single ERC-1155 contract can hold many different token IDs, and each ID can represent either a one of a kind item or a fungible-style item that exists in multiple identical copies, like 500 tickets to the same event or 1,000 copies of the same digital collectible. Your wallet tracks a separate balance for each token ID inside the contract, so you might hold 3 units of token ID 7 and 1 unit of token ID 12 in the same contract.
The practical benefit is batching. ERC-1155 supports transferring, minting, or burning multiple token IDs in a single transaction, which spreads the fixed cost of that transaction across more items and generally lowers the average gas cost per item compared to doing the same work one ERC-721 token at a time.
The semi-fungible idea
ERC-1155 is sometimes described as supporting semi-fungible tokens. A simple way to think about this is a raffle ticket or event pass. Before the event, every ticket with the same token ID is interchangeable, you only care that you hold one, not which specific unit. After the event, the organizer might mark that ticket as redeemed or attach a unique record to it, at which point it starts behaving more like a one of a kind collectible. ERC-1155 can model both states inside the same contract, which ERC-721 was not built to do cleanly.
Where you will actually see this on Base
You do not need to check a contract's source code to guess which standard an NFT uses, but a few patterns are common:
- Profile picture collections, single pieces of generative art, and Basenames generally use ERC-721, since each item is meant to be unique and individually tracked.
- Creator platforms built for editions, such as Zora, commonly use ERC-1155 for mints where many people can own a copy of the same post, song, or image at a shared price, because it keeps minting cheaper as the edition size grows.
- Event tickets, loyalty passes, and in-game items that exist in multiple copies tend to favor ERC-1155 for the same batching reasons.
Neither standard is strictly better. ERC-721 is the more straightforward fit when every item genuinely needs to be one of a kind with its own metadata and history. ERC-1155 is the more efficient fit when a project needs many items, some unique and some repeated, without deploying a separate contract for every type.
Why this matters for your wallet and your gas
A few consequences follow directly from the standard a project chose:
- Minting into an ERC-1155 edition is often cheaper per unit than minting a new ERC-721 token, especially for large editions, because the underlying contract was built for that case.
- If a marketplace or wallet lets you select multiple items from the same ERC-1155 collection and send them together, that batch transaction will usually cost less in total gas than sending the same number of ERC-721 tokens separately.
- When you check an NFT on a block explorer like Basescan, the contract's interface tells you which standard it implements. Looking this up before you interact with an unfamiliar collection is a reasonable habit, since it tells you whether you are dealing with unique items or a shared edition, which affects what you are actually buying.
A word on verifying before you trust
Neither ERC-721 nor ERC-1155 token standards are the same as evidence that a collection is scam-free. The standard is a technical interface, not a guarantee about the project behind it. A scam collection can be built on either standard, as discussed in our article on spotting scam tokens. Before you mint or buy, it is still worth checking the contract address against the project's official links and looking at whether the contract is verified, regardless of which standard it uses.
Understanding the difference between these two standards will not stop a bad actor from launching a low quality project, but it will help you read what you are actually holding, and why some NFTs on Base cost less to mint or move than others.