What Is ERC-721?

ERC-721 is the Ethereum standard for non-fungible tokens (NFTs) — digital assets that are unique and not interchangeable. Unlike ERC-20 tokens, which are fungible and identical in value, each ERC-721 token has distinct characteristics that make it one of a kind.

Introduced through an Ethereum Improvement Proposal (EIP) by William Entriken, Dieter Shirley, Jacob Evans, and Nastassia Sachs in January 2018, ERC-721 was designed to solve the limitations of ERC-20 in representing unique assets on the blockchain.

How ERC-721 Works

ERC stands for Ethereum Request for Comments, a framework used to define technical standards for the Ethereum network. ERC-721 operates through smart contracts that comply with both the ERC-721 and ERC-165 interfaces, ensuring compatibility with Ethereum’s broader ecosystem.

Each ERC-721 token contains unique metadata and identifiers, allowing it to represent a wide range of digital or physical assets such as collectibles, real estate, art, or loans.
One of the first real-world uses of ERC-721 came from the popular DApp CryptoKitties, where each digital cat was represented as a distinct token with its own traits and market value.

Benefits of ERC-721

Uniqueness: Each token is distinct and verifiable on the Ethereum blockchain.
Ownership and Provenance: Enables transparent tracking of asset ownership and history.
Versatility: Used to tokenize both digital and physical assets.
Interoperability: Compatible with Ethereum wallets, marketplaces, and DApps that support NFTs.
Innovation: Opened the path for NFT markets, digital collectibles, and metaverse assets.

Conclusion

ERC-721 revolutionized digital ownership by introducing non-fungible tokens to Ethereum. By enabling unique, verifiable, and tradeable digital assets, it laid the foundation for the NFT ecosystem that powers art, gaming, and Web3 innovation today.