ERC-721

Jan 6, 2023 | Updated Jan 6, 2023
ERC-721 is the token standard used on Ethereum to create non-fungible tokens (NFTs). Each token created using the ERC-721 standard is unique and not interchangeable.

What is an ERC-721?

ERC stands for Ethereum Request for Comments. It is a framework for programming how a token launched on Ethereum will function. ERC-721 is the standard used to create non-fungible tokens on the Ethereum network. 

Non-fungible assets are not interchangeable, good examples of this type of asset would be a vintage record, a house or a work of art: all of these derive their value from their unique features, and cannot simply be swapped with another that looks the sale. Similarly, non-fungible tokens are unique units of value that exist on the blockchain.

By contrast, tokens that use the ERC-20 standard, such as Chainlink, Aave or Shiba Inu, are known as fungible, because one token could be replaced with another from the same currency without any change in value

There are currently nine ERC standards, and ERC-721 is the standard that helps users create non-fungible tokens (NFTs). 

What makes each ERC-721 Token Unique?

Tokens created with the ERC-721 standard have a unique metadata and code that makes them distinct from all others. They are irreplaceable and indivisible. The prices of ERC-721 tokens are often influenced by factors like rarity and hype.

ERC-721 tokens contain an underlying smart-contract and exist on the Ethereum blockchain. The creator inputs the unique details of the token such as name, owner and size of the collection, into the base code (the entire body of code for the NFT saved as a file).

What are ERC-721 NFT Use Cases?

One of the most widespread uses of the ERC-721 token standard is for digital art. Publishing art, or any type of media, on the blockchain means that it can be bought, sold and traded via the underlying blockchain network.

NFTs are transforming a number of other industries, by enabling individuals to own a piece of their digital landscape: this can be seen in non-fungible gaming assets, metaverse land and asset, Web3 community memberships, and more. 

Cryptokitties, an Ethereum-based game, was the first game to use the ERC-721 token standard in 2018 to create a digital collection of unique kitties. Play-to-earn (P2E) games also use the ERC-721 standard to create gaming characters or assets for purchase inside the game, such as weapons, houses, and costumes. 

NFTs are also being used to tokenize personal documents and qualifications.

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