x_collection_metadata

An extensible Solana NFT collection metadata pseudo-standard.

x_collection_metadata reuses the existing JSON NFT metadata format to add collection-specific attributes to a Metaplex collection mint.

This pseudo-standard would allow data consumers such as markets, rarity sites, tools, etc to automatically process on-chain collections.

Rationale

The new Metaplex collection standard solves the problem of how to “tag” mints in a belongs_to relationship to a parent object.

This allows mints from a variety of sources to belong to one collection on-chain. E.g., mints from multiple Candy Machines, launchpads, auction platforms, custom minters etc can all have the same verified collection address.

The standard also allows creators to delegate collection “tagging” authority to other parties, and the verified creator address at index 0 no longer needs to be the same on all mints.

As the object is just a NFT mint, we can take advantage of the standard JSON NFT data format to attach collection-specific data to the mint on-chain, allowing creators to have a single source of collection “truth” in a permanent store where consumers like markets, tools, rarity sites, etc can query the blockchain for all collection information.

Data Format

Root object fields (Metaplex NFT JSON standard)

Field	Description	Required	Example
name	The name of the collection.	Yes	Friendly Frogs
description	A description of the collection.	Yes	2,121 Friendly Frogs bringing friendship to the metaverse and protecting the Positivity Pond from bad vibes!
image	An image representing the collection.	No	https://arweave.net/t65orC3i_dzdsXmtoa5wC6ZQkCRAeiwM9igf4xK-K2U

Attributes

The attribute type will be prefixed with x. to allow for proper namespacing. Additional standards should use a different prefix to avoid collisions.

Field	Description	Required	Example
x_collection_metadata.version	The version of the x_collection_metadata object. Used to denote backwards-incompatible changes in the data format.	Yes	1
x.id	A pseudo-unique ID for the collection for consumers to use in URLs. Must match a [a-z0-9_] regex.	Yes	friendly_frogs
x.supply	The total number of mints in the collection from all sources.	Yes	2121
x.mints	A pointer to a URI containing the complete mint list for the collection. This should be a JSON array.	No	https://arweave.net/5iv5k68DiHw8dD3fhmRUSDgy_seK8KjAWW_GLWOgljI
x.mints.integrity	An integrity hash of the contents of the x.mints file. Follows the W3C Subresource Integrity standard.	No	sha384-HfsDXK3RbMkuHqh5yIf3+vNbTHGweqRc1uImBv61t8JXxI4pGzZQwrC7vnDz5NnP
x.url.web	A link to the collection website.	No	https://ffsc.io
x.url.twitter	A link to the collection Twitter account.	No	https://twitter.com/FriendlyFrogSC
x.url.discord	A link to the collection Discord.	No	https://discord.gg/friendlyfrogs
x.market.[market].id	A marketplace collection ID.	No	friendly_frog_social_club

Example JSON

{
  "name": "Friendly Frogs",
  "description": "2,121 Friendly Frogs bringing friendship to the metaverse and protecting the Positivity Pond from bad vibes!",
  "image": "https://arweave.net/t65orC3i_dzdsXmtoa5wC6ZQkCRAeiwM9igf4xK-K2U",
  "attributes": [
    {
      "trait_type": "x_collection_metadata.version",
      "value": "1"
    },
    {
      "trait_type": "x.id",
      "value": "friendly_frogs"
    },
    {
      "trait_type": "x.supply",
      "value": "2121"
    },
    {
      "trait_type": "x.mints",
      "value": "https://arweave.net/5iv5k68DiHw8dD3fhmRUSDgy_seK8KjAWW_GLWOgljI"
    },
    {
      "trait_type": "x.mints.integrity",
      "value": "sha384-HfsDXK3RbMkuHqh5yIf3+vNbTHGweqRc1uImBv61t8JXxI4pGzZQwrC7vnDz5NnP"
    },    
    {
      "trait_type": "x.url.web",
      "value": "https://ffsc.io"
    },
    {
      "trait_type": "x.url.twitter",
      "value": "https://twitter.com/FriendlyFrogSC"
    },
    {
      "trait_type": "x.url.discord",
      "value": "https://discord.gg/friendlyfrogs"
    },
    {
      "trait_type": "x.market.magiceden.id",
      "value": "friendly_frog_social_club"
    }
  ]
}