What are an NFT and the ERC-721 standard?

Kristaps Grinbergs
Published in
5 min readDec 30, 2022


The non-fungible tokens, or in short NFTs, have one the most influential roles in the crypto and Web3 scene. These are digital assets that can represent digital art, virtual collectibles, assets in games, and more. Ethereum Foundation introduced the ERC-721 standard in 2017, which helped all the crypto wallets, brokers, and protocols to use this feature in a translatable way between any crypto solution. In this post, we will look more deeply into the ERC-721 standard and explore how it is used in the Solidity programming language for the Ethereum blockchain.

Photo by Choong Deng Xiang on Unsplash.

What is an NFT?

Non-fungible tokens represent unique assets that can't be exchanged, copied, substituted, or divided. Each token has a unique identifier. Therefore, we can see who owns what.

An NFT can represent but is not limited to:

  • digital work of art;
  • virtual collectibles;
  • digital assets in games;
  • ownership rights, for instance, to a real estate;
  • tickets that have unique data like seating place;
  • negative loan like a mortgage.

NFTs are like humans - there are no two people the same.

The ERC-721?



Kristaps Grinbergs

Blockchain, mobile and fullstack developer. Startup founder. Conference speaker. Mentor. Passionate about building products, sustainability and Web 3.0.