ERC-721 Definition: A standard for representing non-fungible tokens (NFTs) on the Ethereum blockchain, allowing for the creation and transfer of unique digital assets.

ERC-721 is a prominent token standard on the Ethereum blockchain that is specifically tailored for non-fungible tokens (NFTs). In the cryptocurrency market, while most tokens are fungible (interchangeable), NFTs stand out as each token is distinct and represents a unique asset or value. ERC-721 is the pioneering standard that paved the way for the creation, transfer, and management of these unique tokens on Ethereum's platform.

To understand the significance of ERC-721, it's vital to grasp the difference between fungible and non-fungible tokens:

Fungible tokens are identical and interchangeable, much like traditional currencies. For example, one Bitcoin or one Ethereum is always equivalent to another of its kind in value.

Meanwhile, each non-fungible token is unique, meaning no two tokens are the same. This uniqueness can be attributed to metadata or specific attributes that each token possesses. NFTs have gained immense popularity for representing digital art, collectibles, virtual real estate, and more.

Because each token is distinguishable from every other token, it's ideal for representing ownership of unique items or assets. As well as this, ERC-721 tokens can interact with other dApps, contracts, or platforms that support the standard. For instance, a virtual sword owned in one game could potentially be used in another game.

Like other crypto assets, NFTs can be bought, sold, or traded on various online marketplaces, often fetching substantial value due to their uniqueness and the demand for the specific asset they represent.

Furthermore, holding an NFT means unequivocal ownership, and it can't be replicated or replaced. Smart contracts can also implement additional features, such as ensuring creators get a percentage of sales whenever the NFT changes hands.

A high-profile example of ERC-721 in action is the virtual collectible platform, CryptoKitties. Users can buy, sell, and breed virtual cats, each represented by a unique NFT. Due to its immense popularity at its peak, CryptoKitties congested the Ethereum network, underscoring the potential and demand for unique digital collectibles.

In conclusion, the ERC-721 standard has reshaped the digital asset landscape, introducing the concept of verifiable digital uniqueness. Whether for digital art, collectibles, or novel applications yet to be imagined, ERC-721 provides the foundation for a burgeoning digital economy centered on unique assets.

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Michelle Legge
By Michelle LeggeHead of Crypto Tax Education
Updated Nov 21, 2023
This article has been fact checked and reviewed as per our editorial policy.