An ERC-721 token is a type of digital token or cryptocurrency that is built on the Ethereum blockchain and follows a set of standard rules and requirements called the ERC-721 protocol. Unlike ERC-20 tokens, which are fungible (meaning each token is interchangeable with every other token of the same type and has the same value), ERC-721 tokens are non-fungible, meaning that each token is unique and has its own specific value.
ERC-721 tokens are typically used to represent ownership or possession of a particular asset, such as a piece of artwork, a collectible item, or a virtual real estate property in a decentralized application (dApp) built on the Ethereum network. Each ERC-721 token has a unique identifier (ID) that distinguishes it from every other ERC-721 token, and this ID can be used to verify ownership or transfer of the token.
The ERC-721 protocol defines a set of functions that every ERC-721 token must implement, including functions that allow users to transfer tokens, get information about a specific token, and approve spending of tokens by other users. These functions ensure that ERC-721 tokens are compatible with the Ethereum network and can be managed by any compatible wallet or exchange.
ERC-721 tokens can be created and managed by anyone who has the technical skills to do so, and there are currently thousands of ERC-721 tokens in circulation. Popular examples of ERC-721 tokens include CryptoKitties, a dApp that allows users to buy, sell, and breed unique digital cats, and NBA Top Shot, a dApp that allows users to buy, sell, and trade unique digital collectibles featuring NBA players.