Create and Host Off-Chain Balances

There are two types of off-chain balances: indexed and non-indexed. See the balances type documentation for more information.

For both options, you must create or have a collection with the desired balances type. The recommended way to create a collection is via the Create form on the BitBadges app. You will be able to enter all self-hosted details directly into the form.

URL Requirements

The URLs should be a GET endpoints accessible to whoever needs it (e.g. BitBadges indexer). It is your responsibility to handle CORS errors and such yourself.

Non-Indexed Balances

For non-indexed balances, you simply need to set up a server which can return the current balances for a specified Cosmos address.

Couple notes:

• The URL stored on-chain must have {address} as a placeholder for the address to query.

• The URL param is expected to support converted Cosmos addresses. It is up to you whether you want to support native addresses as well, but converted Cosmos address support is mandatory. See here for more information.

Example:

On-Chain URL: "http://localhost:3000/nonIndexed/{address}"

app.get('/nonIndexed/:address', async (req, res) => {
  const address = req.params.address; 
  const cosmosAddress = convertToCosmosAddress();
  
  //custom logic - (e.g. check subscription status or check some local DB value)

  const balances: Balance<bigint>[] = [...];
  return res.status(200).send({ balances });
});

See here for an example creation Msg. See here for how we implement the first Ethereum tx badge.

Indexed Balances

Step 1: Create Your Map

The map is simply a cosmosAddress/listId -> Balance<NumberType>[] map. You can create this yourself by using the OffChainBalancesMap<NumberType> type.

Note that if you use address list IDs for the keys (see here to learn more), the corresponding address list must be a whitelist (whitelist = false) and should be stored on-chain for reproducability (not off-chain via the BitBadges servers or somewhere else). You should also not allocate more badges in this map than what was created on-chain (via the "Mint" address). The BitBadges indexer / API will throw an error in the above cases.

You may also find the createBalanceMapForOffChainBalances function helpful.

const transfers: TransferWithIncrements<bigint>[] = [...];

const balanceMap = await createBalanceMapForOffChainBalances(transfers);

See https://bafybeiav4hvef6co2sfpmldqn24tmjzrzfbi6d74q5n2sbks4rhnativbq.ipfs.dweb.link/ for an example.

Step 2: Host your map as a JSON file via some URL

This can be via IPFS or any method of your choice.

Note permanent storage (i.e. IPFS) coupled with not being able to update the URL on-chain will make your balances permanent and immutable. This can be a good option if you want your collection to be frozen, non-transferable, and immutable.

Step 3: Create Your Collection

Create your collection and specify your URL via the offChainBalancesMetadata timeline. Decide whether you want to be able to update the URL in the future or not. Set the managerTimeline and canUpdateOffChainBalancesMetadata permission accordingly. Do not overallocate via badgesToCreate.

See here for an example.

Future Refreshes / Updates

In the future, if you are allowed to update the URL on-chain you can do so via another MsgUpdateCollection transaction. This will auto-trigger a refresh on the BitBadges API / indexer as well.

You can also just update the balances JSON returned by the URL as well without interacting with the blockchain (i.e. URL stays the same). Note that the BitBadges indexer / website caches balances. To trigger a refetch manually, you can use the POST /api/v0/refresh endpoint or do it directly on the website.