ERC-721-NFT

Ethereum non-fungible NFT standard ERC-721.

Definition

ERC-721 mandatory functions: balanceOf(owner), ownerOf(tokenId), safeTransferFrom(from, to, tokenId), transferFrom(from, to, tokenId), approve(approved, tokenId), setApprovalForAll(operator, approved), getApproved(tokenId), isApprovedForAll(owner, operator). Events: Transfer, Approval, ApprovalForAll. ERC-721 Metadata extension (name, symbol, tokenURI). Markets: OpenSea, Blur, Magic Eden, LooksRare. Examples: Bored Ape Yacht Club (BAYC, ~$1.5B), CryptoPunks (~$1.7B), Art Blocks.

Origin

ERC-721 proposed January 2018 by William Entriken and co-authors ; EIP-721 standard finalised June 2018 ; CryptoKitties first implementation 2017 ; 2021 NFT boom.

Example in context

Yuga Labs deploys Bored Ape Yacht Club ERC-721 smart contract April 2021 ; 10000 unique ape NFTs ; cumulative trading volume >$3 billion on OpenSea, Blur, LooksRare markets.

Related terms

• ERC-20 — fungible standard.