What Is NFT Metadata? Where Is NFT Metadata Stored?

NFT Metadata is the concept used to refer to data that contains information about other data.

Göknil Bağatarhan

NFTs represent unique digital assets that are traded on the blockchain network. The value of an NFT depends on what it represents, such as an image, video, audio, or gaming asset. To determine what an NFT represents, metadata is used.

Metadata represents data that provides information about other data. In the case of an NFT, it provides information about the main features of the NFT, including the asset's name, description, and anything else its creator considers important. Typically, an NFT metadata also includes the images that give value to an NFT and links to other primary digital assets.

Since NFT Marketplaces use metadata to present NFTs to buyers and sellers, this metadata needs to be in a form that marketplaces can understand.

The most widely used format for NFT metadata is JavaScript Object Notation (JSON). JSON does not impose any restrictions on the structure of the data contained in it. The JSON schema describes the names of the entity's properties and what kind of values are acceptable for each property.

Where Is NFT Metadata Stored?

An NFT is a physical or digitally created asset that documents the ownership of rights to the asset through blockchain technology. Depending on the nature of the NFT created, it can be in formats such as audio or video. Storing the entire data of any NFT on the blockchain network can be quite costly. Therefore, only the information pertaining to the NFT is stored on the blockchain.

NFT metadata and formats that express NFT, such as images and audio, are stored in a system called the InterPlanetary File System (IPFS). IPFS is a Peer to Peer file sharing system.

The NFT metadata is converted into URL format and transferred to the smart contract.

How Does NFT Metadata Work?

A main component that allows non-fungible tokens to work is NFT metadata. NFTs provide a link to data outside of smart contracts, allowing the network to reference off-chain data. Typically, NFT metadata uses IPFS, a peer-to-peer system for protecting and storing multimedia files. IPFS helps make NFTs resilient to changes over time and protects users from NFTs that depend on centralized servers and fragile URL rules.

A content ID (CID) is generated for each file saved to the IPFS system and distributed among independent storage providers. For this reason, IPFS is considered a special type of file system as it does not operate similarly to other file systems.

The metadata stored within the IPFS system is then returned to the smart contract as a hash and pinned to the contract. The resulting URL is saved in the contract's repository and linked to the ID of the corresponding token. The same URL is parsed into a JSON on the web, which has a clear structure and properties. When integrated with marketplaces, it needs specific fields such as name, description, and image to properly display content.

What Are the NFT Metadata Standards?

NFT metadata standards leverage the standards used to create NFTs:

ERC-721
ERC-1155

ERC-721

ERC-721 is the first official standard for the adoption of NFTs. ERC-721 ensures that all tokens are non-fungible and have unique token IDs. Tokens created with ERC-721 cannot be exchanged for any tokens of a type other than its own.

ERC-1155

The ERC-1155 standard extends ERC-721 to support issuing multiple tokens on the same smart contract. This allows for more efficient creation of different tokens, which helps make NFT gaming use cases more practical. ERC-1155 combines features of the ERC-20 and ERC-721 standards. In other words, ERC-1155 supports different types of tokens on the same smart contract.

It enables the creation of fungibles, semifungibles and NFTs on a single smart contract and the simultaneous execution of swaps.

How Can You View Any NFT Metadata?

When an NFT is bought, a set of properties are assigned to the bought NFT. Information about these assigned properties is stored in metadata. The token's metadata is immutably recorded on the blockchain. This record contains information about the token's meaning, owner and transactional activity history.

Viewing any NFT metadata, verifying ownership, and tracking transaction history becomes possible through NFT viewing and verification services. Through these services, the token ID and contract address can be linked and verified to the actual owner of the content using a marketplace database.

In addition, the metadata of any NFT can be viewed through smart contracts. Access to the NFT's smart contract is required. Metadata should be accessible for review and verification under the details section of the contract.

To view an NFT, the Uniform Resource Identifier of the NFT contains the location of the NFT's image. The JSON metadata output should have an image value that links directly to the NFT image. After switching to the selected image, right-clicking on it completes the download.