What are standard NFT specifications?

Features of an NFT

An identifier

All NFTs have an identifier - this is an uint256 value that serves as an ID.

NFT name

This is the name of the specific asset represented by the NFT, for example CryptoPunk #123.

Description

This describes the asset which is represented by the NFT.

Image

This is a link to an image of the asset which is represented by the NFT. This is the image that is displayed on NFT marketplaces like OpenSea.

External Link

This is a link to the location of the asset represented by the NFT. This could point to a centralised storage platform, like AWS, or a decentralized one like IPFS.

Attributes

These are the features of the asset represented by the NFT, for example characteristics like background colour. 

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Features of the smart contract (managing the transferability of the NFT)

A transfer mechanism

In addition, it is common for NFTs to have a transfer mechanism; the element of the smart contract that allows the token to be transferred between owners’ wallets. Transfers can only be initiated by the NFT owner, an approved address (coded into the contract) or an approved operator of the wallet that currently holds the NFT.

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Transfer mechanisms are able to specify conditions under which the transaction will fail, or throw. These conditions include:

• If the contract is paused
• If an address is blacklisted
• If the transfer is unsafe
• If the transaction fee is not paid

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Royalty function

Seller fee

This is the percentage of the sale price that must be paid to the fee recipient (often the creator).

Fee recipient

This is the address of the wallet that is due the royalties on the sale.

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