Metadata

The Standard

CIP-0025 is today the standard for NFTs

CIPs/README.md at master · cardano-foundation/CIPsGitHub

Metadata

The metadata is a JSON where we define each NFT.

{
  "721": {
    "<policy_id>": {
      "<asset_name>": {
        "name": <string>,

        "image": <uri | array>,
        "mediaType": image/<mime_sub_type>,

        "description": <string | array>,

        "files": [{
          "name": <string>,
          "mediaType": <mime_type>,
          "src": <uri | array>,
          <other_properties>
        }],

        <other properties>
      }
    },
    "version": <version_id>
  }
}

The required fields are:

{
  "721": {
    "<policy_id>": {
      "<asset_name>": {
        "name": <string>,
        "image": <uri | array>,
      }
    }
  }
}

Where

• 721: The tag "721" indicates this is NFT

  • <policy_id>: The id of the policy generated based on expiration and the hash of the public keys.

    • <asset_name>: The name you want to give the asset, with no special characters or spaces

Note: 721, is inherited from https://eips.ethereum.org/EIPS/eip-721

Clay Invaders Metadata

{
  "721": {
    "32c4d39b4db9bfea17b92159e9e29b30888a8a72b5e14ec00c5d2b27": {
      "ClayInvaders02486": {
        "name": "ClayInvaders #02486",
        "description": [
          "ClayInvaders invading galaxies and #Cardano with their",
          " magical, mysterious and clumsy ways."
        ],
        "image": "ipfs://QmdvnVLYBqjsq5NZrcY58PLfAdocy7AzCftkY3LQZPxbrk",
        "files": [
          {
            "mediaType": "image/png",
            "src": "ipfs://Qman36W8yJ4itjfp1m43vssmRNfoMtnLHetQLbXEA3EJNs"
          }
        ],
        "mediaType": "image/png",
        "Attributes": {
          "Galaxy": "Condor 1",
          "Spaceship": "None",
          "Planets": "One",
          "Pet": "None",
          "Horns": "Pink Neon 1",
          "Eyes": "Two: Green",
          "Brows": "White Cut",
          "Mouth": "Smile Arrow",
          "Bandages_Head": "None",
          "Accessories": "None",
          "Suit": "Doctor"
        },
        "Publisher": "www.clayinvaders.art",
        "Twitter": "@clayinvaders",
        "Type": "Crew"
      }
    }
  }
}

Notes:

• Top-level image is the image that is used as a thumb in external sites like pool.pm or jpg.store

• The Image inside the files is the full size (2000x2000)

• Type: We define each NFT as a Spaceship, Crew, or Passenger

• Describing all traits inside the Attributes tag, it's not a standard, but a good practice

New CIP

(we suppose this section will be updated soon)

There is a new standard in discussion (proposed by Alessandro/Berry, as usual, 😂 ) but not so many projects using it yet.

https://github.com/cardano-foundation/CIPs/tree/master/CIP-0067