GLOSSARY · BLOCKCHAIN & WEB3
ERC-721
Standard for non-fungible tokens (NFTs) on Ethereum, used for unique assets such as art, collectibles or digital property.
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What is ERC-721?
ERC-721 is a proposed token standard for Ethereum and EVM-compatible networks that defines how to implement non-fungible tokens (NFTs): unique, indivisible and traceable digital assets. Unlike the ERC-20 standard, where all tokens are identical and fungible, in ERC-721 each token has a unique tokenId, which makes it possible to represent unique assets with their own characteristics. This standard allows each token to be linked to a URI that points to its metadata, usually in JSON format, where the name, image, attributes and any relevant data are described. It is the technical basis that has allowed the development and explosion of the NFT ecosystem, being adopted by digital art projects, music, virtual real estate, digital certificates, decentralized domains (such as ENS) or digital identities.
ERC-721 includes standard features such as ownerOf(), transferFrom(), approve() and setApprovalForAll(), allowing for interoperability with marketplaces such as OpenSea or LooksRare. It also covers the logic of individual property, secure transfer, and third-party authorization, making it a very solid framework for managing unique digital assets. Although its gas efficiency may be limited compared to ERC-1155 when managing multiple NFTs, its simplicity and standardization make it the preferred choice when it is necessary to represent assets in a completely individualized way.
Learn more: What are smart contracts and what are they used for?
Explained simply
ERC-721 is like the template for creating NFTs, those unique digital objects that don't repeat themselves. You can use it to make digital art, music, trading cards, video game characters, or anything you want that's special and different from the others. Each NFT has its own number and data, making it unique.
ERC-721: key points
- Standard for representing non-fungible tokens (unique and unrepeatable)
- Each token has its own ID (
tokenId) and associated metadata - Ideal for NFTs for art, music, gaming objects, certificates or identities
- Compatible with marketplaces and wallets that support the standard
- Enables transfer, authorization and ownership verification functions
ERC-721: advantages
- Unique identification: each token represents a unique digital asset
- Broad adoption: it is the most recognized and compatible NFT standard
- Transparency and traceability: everything is recorded on the blockchain
- Creative flexibility: adapts to multiple industries, from art to education
- Interoperability with marketplaces, wallets and DeFi protocols
ERC-721: disadvantages
- Less efficient in gas if many NFTs are issued at the same time
- Does not support native batch transfers like ERC-1155
- Limited scalability if you need to manage large volumes
- Dependency on external metadata if they are not stored on-chain
- Higher operating cost for each individual token
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