What is NFT?

An NFT, a non-fungible token, is a token with a unique identifier: one contract issues many, but each has its own id, owner and metadata. That is the whole mechanism. The image, the membership, the domain name or the in-game item the NFT represents is whatever the metadata points to; the chain only records who owns identifier number 4,021 of a given contract.

Ownership and value are separate questions. Ownership is unambiguous and public: the contract says which address holds the token. Value is a market question with thin data, because most NFTs trade rarely. The convention is to value a holding at its collection floor price, the cheapest listing in the same collection, which is a conservative estimate and the only one that can be read consistently across thousands of collections.

NFTs exist on most chains with smart contracts, and each ecosystem has its own standard and marketplace: ERC-721 and ERC-1155 on Ethereum and other EVM chains, Metaplex on Solana, and marketplaces such as OpenSea and Magic Eden that publish floor prices. Wallets that hold NFTs also collect spam, unsolicited tokens with links in the metadata designed to be clicked.

A portfolio tracker has to decide whether to count NFTs into net worth at all, and at what price. TrueHold counts them at floor price from Magic Eden and OpenSea, next to tokens, DeFi and exchange balances, and reads them from the address like everything else. A floor-price valuation can be wrong in both directions for any single item, but across a wallet it is the honest number.

Reading your own NFTs is the same as reading tokens: the address holds them and the chain says so. What the chain does not say is what they are worth, which is why the floor price convention matters. If you hold something rare inside a collection, the floor undervalues it; if the collection has died, even the floor is optimistic. Treat NFT value in a portfolio total as a floor, literally, and adjust by hand for the pieces you know.