ERC-1155

In ERC-1155 each ID carries a balance. If an ID has a supply greater than one with indistinguishable copies it is fungible; if its supply is one, it behaves like an NFT. The standard combines ERC-20 and ERC-721 capabilities under a single contract address. balanceOf(address, id) reads one balance and balanceOfBatch retrieves several owner-id pairs in one call. safeTransferFrom moves one type and safeBatchTransferFrom moves several in a single transaction, with no wrapper contract, which lowers gas. Approval is per operator via setApprovalForAll, and it emits the TransferSingle, TransferBatch, ApprovalForAll and URI events.

The EIP-1155 standard, created on 17 June 2018 and Final since 2019, was authored by Witek Radomski, Andrew Cooke, Philippe Castonguay, James Therien, Eric Binet and Ronan Sandford, from the Enjin orbit. It uses ERC-165 for interface detection and requires contract recipients to implement onERC1155Received or onERC1155BatchReceived. It matters for its gas efficiency and unified management of mixed inventories, with batch minting and burning.

ERC-1155 is dominant in gaming, where fungible items such as potions coexist with unique pieces such as skins. Its semi-fungible nature links it to ERC-3525, though the mechanism differs: ERC-1155 separates fungibility by ID, while ERC-3525 introduces value inside a single token. In tokenization it serves to represent homogeneous batches alongside unique assets in one collection, and it is compatible with ERC-2981 for royalties. Real examples include Enjin (the standard's driver) and The Sandbox, whose in-game ASSETs use ERC-1155.