What is an ERC-721?

ERC-721 is a non-fungible token (NFT) standard used in the Ethereum blockchain. It is a type of smart contract that represents a unique, one-of-a-kind digital asset that cannot be divided, duplicated, or exchanged on a one-to-one basis with other digital assets. In other words, NFTs are not interchangeable with each other.

Each ERC-721 token has its own distinct characteristics, such as a unique serial number, a set of attributes, or specific data. They are used to represent a wide range of digital assets, including collectible items, in-game items, virtual real estate, digital art, and other unique digital items.

One of the key benefits of using ERC-721 tokens is that they allow for the creation of truly unique and valuable digital assets. This can be seen in the growing market for NFTs, where individuals and businesses are buying and selling digital assets for thousands and even millions of dollars.

ERC-721 tokens are also interoperable, meaning that they can be used across different platforms and applications, making it easy for individuals and businesses to take advantage of the growing NFT market. Additionally, because ERC-721 tokens are built on the Ethereum blockchain, they are secure and transparent, providing an extra layer of protection for owners and investors.

In summary, ERC-721 is a token standard that enables the creation of unique, one-of-a-kind digital assets in the Ethereum blockchain. It allows for the creation of valuable NFTs that can be used across different platforms and applications, providing a secure and transparent way to represent and trade unique digital assets.

Simplified Example

Think of ERC-721 tokens like trading cards. Each trading card is unique and has its own special design, picture, and information on it. Some trading cards are very rare and valuable, while others are more common. Just like trading cards, ERC-721 tokens are unique digital assets that can be bought, sold, and traded.

For example, let's say you have a trading card of your favorite basketball player, LeBron James. This trading card is special and one-of-a-kind, just like you. Just like you can show your LeBron James trading card to your friends, you can show your ERC-721 token to others on the internet.

And just like you can trade your LeBron James trading card with someone else for a different trading card, you can also trade your ERC-721 token for a different one. The difference is that ERC-721 tokens are stored on the internet and can be seen by people all around the world, not just in your neighborhood.

Who Invented ERC-721?

While the specific originator of the term remains unknown, the proposal for the ERC-721 standard was initially presented to the Ethereum community by Dieter Shirley on January 24, 2018. His proposal, titled "EIP-721: Non-Fungible Token Standard," introduced the notion of non-fungible tokens (NFTs) and established the framework for creating and managing unique digital assets on the Ethereum blockchain. Although Shirley's proposal marked the beginning, the development of the ERC-721 standard evolved into a collaborative endeavor with several other contributors playing essential roles. William Entriken significantly contributed to the design and specification of the ERC-721 standard, emphasizing its technical aspects and implementation. Jacob Evans played a crucial role in documentation and community engagement, fostering awareness and understanding among developers. Nastassia Sachs provided valuable feedback and insights during the development process, contributing to the refinement of the standard and ensuring its functionality.


CryptoKitties - CryptoKitties is a blockchain-based virtual game where players can collect, breed, and trade unique digital cats. Each CryptoKitty is an ERC-721 token, representing a one-of-a-kind digital cat with its own unique attributes and characteristics.

NBA Top Shot - NBA Top Shot is a blockchain-based platform where fans can buy, sell, and trade officially licensed NBA highlights in the form of ERC-721 tokens. Each token represents a specific, verified moment in NBA history, such as a dunk or a three-pointer, and can be used to relive these moments and show off ownership of them to others.

Art Blocks - Art Blocks is a platform that enables artists to create and sell unique digital art as ERC-721 tokens. Each piece of digital art is a unique, one-of-a-kind ERC-721 token, providing a secure and transparent way for artists to sell their digital creations to a global audience.

  • ERC-223: A newer token standard for creating tokens on the Ethereum blockchain.

  • ERC-777: A type of Ethereum smart contract standard for tokens.