In 2017, ERC-20 was the Ethereum token standard that launched a thousand ICOs. Today, ERC-721 launched a thousand non-fungible tokens (NFTs). So what is ERC 721? ERC-721 tokens differ from ERC-20 tokens in that ERC-721 tokens are non-fungible. In this article, we will discuss what is ERC 721 and how ERC-721 NFTs are produced.
What is ERC-721?
ERC-721 is a free and open standard that describes how to build non-fungible or unique tokens on the Ethereum blockchain. While most tokens are fungible (each token is identical to the others), ERC-721 tokens are all unique.
ERC-721 is the token standard for non-fungible tokens (NFTs) on Ethereum. Fungible means fungible and fungible; Bitcoin is fungible because any Bitcoin can substitute for any other Bitcoin. On the other hand, each NFT is completely unique. One NFT cannot replace another.
All NFTs have a uint256 variable called tokenId, so for any ERC-721 contract, the uint256 tokenId must be globally unique to the contract address. A dapp can have a "converter" that takes a tokenId as input and outputs some cool image, like a zombie, weapon, skill, or magical kitty!
How did ERC-721 NFTs produce?
A token is just a smart contract or piece of code on Ethereum. ERC-721 tokens are created by writing a piece of code in a smart contract programming language like Solidity that follows the same basic template or codebase.
The creation of blockchain-based non-fungible tokens allows
- Tangible property (house, art, and vehicles)
- Virtual Collectibles (Cryptokitties, Rare Pepe, Collector Cards)
-Negative Assets (Loans)
To create ERC-721 tokens, contracts must be compatible with both ERC-721 and ERC-165 interfaces.
Hopefully, you will understand what is ERC-721 and how ERC-721 NFTs are produced. You can even program extra functionality into your NFT, but what's really interesting is how the NFT interacts with other smart contracts.

















