On-chain Metadata

1 min read

Pronunciation

[on-cheyn met-uh-dey-tuh]

Analogy

On-chain metadata for an NFT is like having the artist's signature, the artwork's title, and its description engraved directly onto the frame of a physical painting, which is then sealed in a tamper-proof vault (the ). metadata would be like having that information on a separate paper label that could get lost or changed.

Definition

Descriptive data about a , particularly a (NFT), that is stored directly on the itself rather than on a separate server or decentralized storage network like . This ensures the metadata's permanence and align with the 's.

Key Points Intro

On-chain metadata stores an NFT's descriptive attributes directly on the , maximizing its persistence and .

Key Points

NFT attributes (name, description, image data, traits) are recorded on the blockchain.

Offers greater permanence and resistance to censorship or data loss compared to off-chain storage.

Can be more expensive due to the cost of storing data on-chain.

Often used for generative art projects or NFTs where data integrity is paramount.

Example

Autoglyphs, an early generative art NFT project, stores all the data needed to generate its artwork directly within its . This means the art's appearance is determined entirely by code and data, and will persist as long as exists, without relying on any external servers or .

Technical Deep Dive

Storing metadata usually involves encoding the data (e.g., SVG image code, text attributes, generative art algorithms) directly into the NFT's or as part of its URI, if the URI itself resolves to an data source (e.g., a `data:` URI). This makes data retrieval more direct but significantly increases and minting costs due to the associated with storage. Projects often make trade-offs, storing only essential or generative metadata and linking to larger files (like high-res images) .

Security Warning

While on-chain metadata is highly durable, ensure that any functions that might alter this metadata (if designed to be mutable) are properly secured and access-controlled. For fully generative art, verify the rendering logic if you are concerned about exact visual representation.

Caveat

Storing large amounts of data is often prohibitively expensive, which limits the complexity or size of metadata that can be fully . Many projects use a hybrid approach, storing a pointer to metadata stored (e.g., on ).

Related Terms

Smart Contract

Immutability

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