The Cardano NFT Guides
UNDERSTANDING CARDANO NFT STANDARDS

CIP 25

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IN THIS LESSON

CIP 25 defines how essential information about your NFT is stored directly on the Cardano blockchain. This includes the NFT's name, image, and more, creating a permanent link between the asset and its details.

CIP 25, the Media Token Metadata Standard, provides a way to attach detailed information to tokens on the Cardano blockchain. Unlike Ethereum, and similar blockchains, where tokens and their associated data are managed through smart contracts, Cardano's architecture stores tokens natively on the blockchain ledger itself. This structural difference requires a unique approach to linking metadata to a token. CIP 25 does this by leveraging Cardano's ability to include metadata within a token's minting transaction.

Essentially, CIP 25 states that metadata for a token will be included in the same transaction that mints the token, creating an immutable and traceable connection between the token and its metadata.

The metadata structure defined in CIP 25 supports multiple tokens and policies to be minted within a single transaction, allowing for efficiency and flexibility. The standard requires certain fields, such as the token's name and image - specified as a URI - and allows for additional optional fields to capture more detailed attributes. This could include descriptions, file details, and other properties that give context or enhance the token.

CIP 25 sets a precedent for backward compatibility, with a version property included to manage future updates and changes to the standard. This ensures that as the Cardano ecosystem evolves, the tokens minted under this standard will continue to be supported and understood across various platforms and services within the ecosystem.

CIP 25 Key Points:

  • Transactions that contain NFT metadata are tagged with the special label "721". This makes finding them easy.

  • CIP 25 has a clear JSON format defining essential metadata, including:

    • name: Your NFT's title

    • image: A link to the image representing the NFT

    • description (optional): A space for a description of the NFT

    • version: This ensures compatibility as the standard may evolve over time.

  • As long as the token policy is open, the metadata can be updated. Mint more of the same token with new metadata (still using label "721"). This new information becomes the official metadata for the token.

  • The format is intentionally simple. CIP 25 provides a flexible foundation, allowing more details to be added as different NFT use cases emerge.