Metadata

Metadata is the descriptive information attached to a token — for an NFT, typically its name, description, image link, and a list of traits or attributes. The blockchain itself records who owns which token ID; the metadata tells wallets and marketplaces what that token ID actually represents and how to display it.

Most NFT contracts follow a standard where each token exposes a URI pointing to a JSON file. That file might say the token is "Cool Cat #204," link to an image, and list traits like "blue hat" and "sunglasses" that marketplaces use to compute rarity. The JSON and the image are often stored on IPFS or another storage system rather than on the blockchain itself, because storing large files on-chain is expensive.

A common misconception is that NFT metadata is always permanent; if it points to an ordinary web server, the project can change or lose the files, whereas content-addressed storage like IPFS makes silent swaps much harder. When evaluating an NFT, where the metadata lives matters as much as the token itself — the token proves ownership, but the metadata defines what is owned.