How to build a badge-gate (technical explainer)

Key Terms

Badge Spec	The blueprint of a Badge, from which several Badges can be minted.
Badge	The actual EIP4973 NFT held in someone’s wallet.
Raft	What we call communities and sub-communities at Otterspace
Raft Token	The ERC721 token used to identify a community. The token id is the unique identifier of the community.

Finding the Badge Spec id

You can easily build token gate for your community or your tool using Otterspace Badges. Firstly you need to get the ID of the Badge spec that you used to issue badges to different addresses.

You can find the Badge spec id in the url of the Badge page.

https://beta.otterspace.xyz/badges/bafyreifcjs56sk5gseb75e45rjebh4kwln3trwi6aphhacf727lkshq74e

Fetching all the holders of a Badge Spec

You can use our subgraph to fetch all the badge owners of that spec

{
  badgeSpec(id: "bafyreicl3unvw6tvzjfduvrhxbfi74gsob6mpf6ekn3s2nkopqz2phtx7e") {
    id
    name
    description
    image
    expiresAt
    totalBadgesCount
    badges {
      id
      owner
      createdAt
    }
  }
}

Does an address hold a Badge belonging to this spec?

If you already know the address of a user, you can simply check if this address owns a badge with the spec that you intend to gate. For example, see the query below. Here we’re checking if the address 0x77B476429826C5ba77885D08F272d89D8F1Ed0e4 owns a Pioneer badge issued by the Otterspace community. Note, communities are expressed as Rafts in Otterspace.

{
  badges(where: {owner: "0x77B476429826C5ba77885D08F272d89D8F1Ed0e4", spec: "bafyreicl3unvw6tvzjfduvrhxbfi74gsob6mpf6ekn3s2nkopqz2phtx7e"}) {
    id
    createdAt
    owner
    createdAt
    spec {
      id
      name
      raft {
        id
        name
      }
    }
  }
}

And if you’d like to check if an address owns one of the badges, simply use spec_in filter

{
  badges(
    where: {owner: "0x77B476429826C5ba77885D08F272d89D8F1Ed0e4", spec_in: ["bafyreicl3unvw6tvzjfduvrhxbfi74gsob6mpf6ekn3s2nkopqz2phtx7e","bafyreia2lnu2jmr6sqqijzd3xt6fw2qriyy2vbq57zikzrkeyxfvlpqp3i"]}
  ) {
    id
    createdAt
    owner
    createdAt
    spec {
      id
      name
      raft {
        id
        name
      }
    }
  }
}

Filtering out expired Badges

One thing that makes Badges different from other NFTs is that they can expire. Expired Badges shouldn’t be able to be used to access spaces and resources. You can check if a Badge is expired by looking at the expiry date in the metadata.

Filtering by community

If you are building a token-gating UI, you probably want to allow a community to select from the Badge Specs belonging to that community. As mentioned above, a community / sub-community is referred to as a ‘Raft’ in Otterspace.

The unique identifier of a Raft is the Token Id of an ERC721 token which is airdropped to the community during its formation. The Raft Id can be found in the community’s profile url.

https://beta.otterspace.xyz/communities/1