ERC-721

The ERC-721 (Ethereum Request for Comment 721) is a free, open standard on the Ethereum blockchain that defines the minimum interface for Non-Fungible Tokens (NFTs), ensuring that each token is unique, indivisible, and represents a distinct asset or piece of data. Adopted in January 2018, this standard is the foundational technical specification that enabled the massive growth of digital collectibles, digital art, and tokenized real-world assets by providing a consistent way to track ownership and manage transfers.