Verified Collections

Certified Collections enables NFTs – and tokens in general — to be grouped together and for that information to be verified on-chain. Additionally, it makes it easier to manage these collections by allocating data for them on-chain.

This feature provides the following advantages:

• Easy to identify which collection any given NFT belongs to without making additional on-chain calls.
• Possible to find all NFTs that belong to a given collection (Check the Recipe to see how).
• Easy to manage the collection metadata such as its name, description and image.

Collections are NFTs

In order to group NFTs — or any token — together, we must first create a Collection NFT whose purpose is to store any metadata related to that collection. That's right, a collection of NFT is itself, an NFT. It has the same data layout on-chain as any other NFT.

The difference between a Collection NFT and a Regular NFT is that the information provided by the former will be used to define the group of NFTs it contains whereas the latter will be used to define the NFT itself.

Associating NFTs to Collection NFTs

Collection NFTs and Regular NFTs are linked together using a "Belong To" relationship on the Metadata account. The optional Collection field on the Metadata account has been created for that purpose.

• If the Collection field is set to None, it means the NFT is not part of a collection.
• If the Collection field is set, it means the NFT is part of the collection specified within that field.

As such, the Collection field contains two nested fields:

• Key: This field points to the Collection NFT the NFT belongs to. More precisely, it points to the public key of the Mint Account of the Collection NFT. This Mint Account must be owned by the SPL Token program.
• Verified: This boolean is very important as it is used to verify that the NFT is truly part of the collection it points to. More on that below.

Differentiating NFTs from Collection NFTs

The Collection field alone allows us to link NFTs and Collections together but it doesn't help us identify if a given NFT is a Regular NFT or a Collection NFT. That's why the CollectionDetails field was created. It provides additional context on Collection NFTs and differentiates them from Regular NFTs.

• If the CollectionDetails field is set to None, it means the NFT is a Regular NFT.
• If the CollectionDetails field is set, it means the NFT is a Collection NFT and additional attributes can be found inside this field.

The CollectionDetails is an optional enum that currently contains only one option V1. This option is a struct that contains the following field:

• Size: The size of the collection, i.e. the number of NFTs that are directly linked to this Collection NFT. This number is automatically computed by the Token Metadata program but can also be set manually to facilitate the migration process. Note that there currently is a MIP in place to deprecate this Size attribute.

Creating Collection NFTs

Creating a Collection NFT is very similar to creating a Regular NFT. The only difference is that we must set the CollectionDetails field as seen in the previous section. Some of our SDKs encapsulate this by requesting a isCollection attribute when creating an NFT.

import { generateSigner, percentAmount } from '@metaplex-foundation/umi'
import { createNft } from '@metaplex-foundation/mpl-token-metadata'

const collectionMint = generateSigner(umi)
await createNft(umi, {
  mint: collectionMint,
  name: 'My Collection',
  uri: 'https://example.com/my-collection.json',
  sellerFeeBasisPoints: percentAmount(5.5), // 5.5%
  isCollection: true,
}).sendAndConfirm(umi)

Nested Collection NFTs

Because Collections and NFTs are linked together via a "Belong To" relationship, it is possible by design to define nested collections. In this scenario, the Collection and CollectionDetails fields can be used together to differentiate Root and Nested Collection NFTs.

Verifying Collection NFTs

As mentioned above, the Collection field contains a Verified boolean which is used to determine if the NFT is truly part of the collection it points to. Without this field, anyone could pretend their NFT to be part of any collection.

In order to flip that Verified boolean to True, the Authority of the Collection NFT must sign the NFT to prove that it is allowed to be part of the collection.

Verify

Once the Collection attribute is set on an NFT, an authority of the Collection NFT can send a Verify instruction on the Token Metadata to flip its verify attribute from false to true. This instruction accepts the following attributes:

• Metadata: The address of the NFT's Metadata account. This is the NFT we want to verify inside the collection.
• Collection Mint: The address of the Collection NFT's Mint account. This is the Collection NFT that is already set on the Metadata account of the NFT but not yet verified.
• Authority: The authority of the Collection NFT as a Signer. This can be the Update Authority of the Collection NFT or an approved delegate with the appropriate role (See "Delegated Authority" page).

Here is how you can use our SDKs to verify a Collection NFT on Token Metadata.

import { verifyCollectionV1 } from '@metaplex-foundation/mpl-token-metadata'

await verifyCollectionV1(umi, {
  metadata,
  collectionMint,
  authority: collectionAuthority,
}).sendAndConfirm(umi)

Unverify

Reciprocally, the authority of a Collection NFT can unverify any NFTs that are part of its collection. This is done by sending an Unverify instruction to the Token Metadata program whose attributes are the same as the Verify instruction.

import { unverifyCollectionV1 } from '@metaplex-foundation/mpl-token-metadata'

await unverifyCollectionV1(umi, {
  metadata,
  collectionMint,
  authority: collectionAuthority,
}).sendAndConfirm(umi)