ERC-721 vs ERC-1155, Explained
The two token standards behind nearly every NFT: how they differ, why both exist, and which one your favorite collection actually uses.
Strip away the artwork, the celebrity endorsements, and the floor prices, and the NFT ecosystem runs on two documents: ERC-721 and ERC-1155. Both are Ethereum standards — shared rulebooks that define how smart contracts must behave — and together they cover almost every non-fungible token in existence.
ERC-721: one token, one identity
Finalized in January 2018 and authored by William Entriken, Dieter Shirley, Jacob Evans, and Nastassia Sachs, ERC-721 was written in direct response to CryptoPunks and CryptoKitties. Both projects had proven that people wanted unique on-chain objects, but both had been forced to improvise their own ownership logic — the Punks famously predate any token standard at all.
ERC-721’s contract is simple to state: each token has a unique ID, exactly one owner at a time, and metadata that distinguishes it from every other token in the contract. The standard defines how ownership is tracked, how tokens move between addresses, and how approvals work. CryptoKitties was effectively its test case; nearly every PFP collection that followed — Bored Apes included — is an ERC-721 contract.
The trade-off is granularity. In ERC-721, every single token is its own snowflake. That is perfect for art and collectibles, and wasteful for anything that comes in identical copies.
ERC-1155: many tokens, one contract
ERC-1155, led by Enjin’s Witek Radomski and finalized in June 2019, was built for games. Its key insight: a game needs both unique items (this specific legendary sword) and fungible items (five hundred gold coins), and deploying a separate contract for each item type is absurd.
An ERC-1155 contract can hold any number of token types at once. Each type has an ID and a supply — a supply of one makes it effectively non-fungible, a supply of a million makes it a currency. Crucially, the standard supports batch transfers: move ten different item types in a single transaction instead of ten separate ones, saving enormous amounts of gas.
Which one does the ecosystem use?
| ERC-721 | ERC-1155 | |
|---|---|---|
| Uniqueness | Every token unique | Per token type |
| Typical use | Art, PFPs, deeds | Game items, tickets, editions |
| Batch transfers | No | Yes |
| Famous examples | CryptoPunks (pre-standard), BAYC | Enjin items, OpenSea editions |
The short version: if it hangs in a gallery, it is probably ERC-721. If you equip it, stack it, or spend it in a game, it is probably ERC-1155. Both are still actively used, and both outlived the boom that made them famous — which is exactly what a good standard is supposed to do.