A non-fungible token (NFT) is a unit of data stored on a digital ledger, called a blockchain, that certifies a digital asset to be unique and therefore not interchangeable. NFTs can be used to represent items such as photos, videos, audio and other types of digital files. Access to any copy of the original file, however, is not restricted to the buyer of the NFT. While copies of these digital items are available for anyone to obtain, NFTs are tracked on blockchains to provide the owner with a proof of ownership that is separate from copyright.

there has been an increased interest in using NFTs. Blockchains like Ethereum, Flow, Tezos, and Goods have their own standards when it comes to supporting NFTs but each works to ensure that the digital item represented is authentically one-of-a-kind. NFTs are now being used to commodify digital assets in art, music, sports, and other popular entertainment.

The NFT market value tripled in 2020, reaching more than $250 million. The rise of NFT transactions has also led to increased environmental criticism. The computation-heavy processes associated with proof-of-work blockchains, the type primarily used for NFTs, require high energy inputs that are contributing to global warming. The carbon emissions produced by the energy needed to maintain these blockchains has forced some in the NFT market to rethink their carbon footprint.