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Bank Coins ​

The Bank Coin is one of the primary fungible token standards used on the Nibiru blockchain alongside ERC20s. This standardization ensures that wallets, exchanges, and smart contracts can interact with all Bank Coins in a consistent manner, similar to how they handle the native NIBI token.

Fungible Assets ​

In the Nibiru ecosystem, the sdk.Coin type represents fungible assets. Each Bank Coin is identified by a unique denomination (denom) and contains a specific amount. The denom serves as a unique identifier for the asset type, while the amount represents the quantity of that asset.

Fungibility: Bank Coins versus NFTs ​

Fungible tokens are equivalent and interchangeable digital assets. These includes familiar tokens like NIBI, ETH, fiat currencies like KRW and USD, and quantifiable voting rights. Non-fungible tokens are distinct and unique and uses to represent items like collectibles, licenses, or deeds of ownership.

Bank Coins as Fungible Tokens ​

The "Bank Coin" is one the main standards for fungible tokens on Nibiru alongside ERC20 tokens. Bank Coins are quite simple and described by two pieces of information: a denomination and an amount.

go
// JSON example: {"denom": "btc", "amount": "123456"}
type BankCoin struct {
    Denom  string   `json:"denom"`
    Amount *big.Int `json:"amount"`
}

A coin denomination, or bank denom for short, is a unique identifier for the asset to be understood by the Nibiru blockchain. For example, NIBI tokens have bank denom "unibi".

Smart Contract Support: All Wasm smart contracts on Nibiru can hold or receive coins. Special contract logic is not needed to enable protocol.

Wallet Compatibility: Bank Coins are compatible with a wide range of wallets and decentralized applications within the IBC ecosystem.

Multi-Chain Compatibility: Bank Coins are a multi-chain standard. They have bridge and IBC support by default. Coins can only be created by the Bank Module on Nibiru, which is essentially an ownerless contract that can mint or burn tokens and manages all transfers of coins.

How do Bank Coins differ from ERC20 tokens? ​

AspectBank CoinsERC-20 Tokens
State ManagementManaged directly by the Bank module in its own key-value storeManaged within each token's smart contract state
Creation ProcessCreated through governance proposals, permissioned modules, or the Tokenfactory moduleCreated by deploying new smart contracts
EfficiencyTypically more gas-efficient due to native implementationGenerally consume more gas due to smart contract execution
StandardizationAll follow the same standard and are handled uniformly by the blockchainCan have variations in implementation, though most follow a standard interface
Balance QueriesQueried through the Bank module's API, which is easy to manage because the same generic query is used for all coins.Queried by calling the ERC20 token's smart contract, as balances are individually stored on each contract.
Transfer MechanismExecuted directly by the Bank moduleExecuted by calling the token's transfer function
Supply ManagementControlled by authorized modules or governanceManaged by the token's smart contract logic
Permissionless CreationPossible via the Tokenfactory moduleInherent (anyone can deploy a new token contract)
Storage EfficiencyMore efficient as all coins share the same infrastructureEach token contract stores its own data separately
InteroperabilityNative to the Bank Module but can be converted to ERC20 via the FunToken systemNative to EVM environments (Nibiru EVM in this case) but can be converted to Bank Coins via the FunToken system

Creating Bank Coins ​

Unlike custom token standards that require smart contract deployment, Bank Coins are a native feature of Nibiru. They can be created through governance proposals or by modules with the appropriate permissions.

Coin Metadata ​

When creating a new Bank Coin, you can specify metadata that describes its properties:

  • Name: The full name of the coin (e.g., "Nibiru")
  • Symbol: A short identifier for the coin (e.g., "NIBI")
  • Description: A brief explanation of the coin's purpose or characteristics
  • DenomUnits: Defines the coin's denomination units and their conversion rates
  • Base: The fundamental unit of the coin, used for internal calculations
  • Display: The default unit for displaying the coin's value to users

Transferring Bank Coins ​

Bank Coins can be freely transferred between accounts using the standard transfer functions provided by the bank module. These transfers are subject to the sender having sufficient balance and any additional logic implemented by custom modules.

Interoperability with Smart Contracts ​

While Bank Coins are native to Nibiru, they can be seamlessly used within the EVM environment through the FunToken system. This allows for Bank Coins to be represented as ERC-20 tokens, enabling their use in smart contracts and DeFi applications.

Key Differences from Custom Tokens ​

  • Native Support: Bank Coins are natively supported by the Nibiru blockchain, requiring no additional smart contract logic for basic functionality.
  • Standardized Handling: All modules and applications on Nibiru can interact with Bank Coins using a consistent API.
  • Efficient: Operations with Bank Coins are generally more gas-efficient than custom token implementations.
  • Governance Controlled: The creation and management of Bank Coins can be subject to on-chain governance decisions.

For more information on working with Bank Coins in your applications or modules, refer to the following resources:

References ​