The ERC-721 non-fungible token standard is an Ethereum (smart-)contract standard that specifies what a non-fungible token (NFT) contract is. In short and simply, an NFT contract simply requires that the tokens minted by the contract are non-fungible by requiring each token to have a unique token identifier. The NFT contract can be publicall queried to learn information such as who owns each NFT.

It’s basically* as simple as that!

NFT-like contracts were possible even before ERC-721 was defined. However, the standard is useful so that all contracts that aim to offer NFT functionalities provide the same interface and terminology to developers.

Use Cases so Far

At the time of writing this article, the topic of NFTs has spun up into a sort of craze. This is not only among crytocurrency enthusiasts — the term “NFT” has also broken into the mainstream. Just a week ago my mother sent me an article about how a nyan cat NFT sold for $605k. I see that the NYT is beginning to auction its columns off as NFTs. And over the last few weeks there have been a significant number of high-grossing NFT sales:

Beyond just these high-bidding items, there are numerous current experiments (many of which began before this recent trend) that use NFTs in many different ways. To name a few:

See the Ethereum foundations page on NFTs for more examples and other details.

I see the current significant use cases for NFTs as falling into two categories:

  • digital art
  • digital collectibles
  • digital history
  • random…

Digital Art

The classic problem (not exclusively) for digital artists is capturing the value of content that, typically, is freely accessible. Aside from the value of owning the copyright to the IP, there is not thing of value that the art consists of that the creator can sell. The best option for many artists is to sell the copyright (permantently or temporarily) and merchandise and to profit off of the brand name that their

Digital Collectibles

Digital History