Note
Terra Classic ships a custom wrapper around the Cosmos SDK x/bankCopy x/bank module to integrate burn tax calculation, keep backwards-compatible CLI commands, and support tax exemptions. This document highlights Classic-specific behaviour.
Overview
x/bankCopy x/bank maintains account balances and handles token transfers. Classic extends it via custom/bankCopy custom/bank to:
- Register a CLI that understands burn-tax exemptions and supports legacy flags.
- Provide simulation helpers that avoid failing due to tax-induced fee shortages.
The core keeper still comes from the Cosmos SDK, so all standard functionality (SendCoinsCopy SendCoins, BurnCoinsCopy BurnCoins, SetBalanceCopy SetBalance) behaves as expected. Tax enforcement happens in the ante-handler (custom/auth/ante/fee_tax.goCopy custom/auth/ante/fee_tax.go) and message server (custom/bank/keeper/keeper.goCopy custom/bank/keeper/keeper.go) rather than inside the bank keeper itself.
Note
Classic uses a legacy amino encoding for messages.
Instead of cosmos-sdk/MsgSendCopy cosmos-sdk/MsgSend, it uses bank/MsgSendCopy bank/MsgSend. It is recommended to use protobuf encoding for new code.
Message types
MsgSendCopy MsgSend
Standard single-sender, single-recipient transfer.
- Burn tax: custom/auth/anteCopy custom/auth/ante deducts burn tax before the bank keeper executes the send unless the sender and recipient are exempt via x/taxexemptionCopy x/taxexemption.
- Tax exemption: Addresses listed in x/taxexemptionCopy x/taxexemption bypass burn tax when sending to other exempt addresses.
- Multiple signers: Not supported; use MsgMultiSendCopy MsgMultiSend or authz with multiple MsgSendCopy MsgSends.
MsgMultiSendCopy MsgMultiSend
Batch transfer with multiple inputs and outputs.
- All inputs must balance with outputs (Σ inputs = Σ outputsCopy Σ inputs = Σ outputs).
- Burn tax is applied per input address that is not fully exempt. The ante-handler computes taxes on each input coin set.
- Non-taxable funds (e.g. contract payouts) propagate via the nonTaxableTaxesCopy nonTaxableTaxes tracking in FilterMsgAndComputeTax()Copy FilterMsgAndComputeTax().
Classic integrations
- Tax module: x/taxCopy x/tax consumes bank keeper APIs to move burn-tax proceeds into the fee collector and splits them between burn, oracle rewards, and treasury.
- Treasury: x/treasuryCopy x/treasury tracks epoch tax proceeds recorded by the tax keeper. Bank transfers supply the raw data.
- Wasm contracts: Contract-executed transfers are taxed unless both the sender and contract are exempt.
Parameters
Subspace: bankCopy bank
| Name | Description | Type | Default |
|---|---|---|---|
| DefaultSendEnabledCopy DefaultSendEnabled | Global flag controlling whether new denominations are send-enabled by default. | boolCopy bool | trueCopy true |
Classic no longer uses the per-denom SendEnabledCopy SendEnabled list; governance proposals can still toggle DefaultSendEnabledCopy DefaultSendEnabled if required.
CLI usage
Classic exposes terrad tx bank sendCopy terrad tx bank send and multisendCopy multisend with automatic burn-tax handling. Clients only need to specify the desired amount; taxes are deducted from the input coins, reducing the received amount accordingly.
API queries
x/bankCopy x/bank keeps the standard gRPC and REST endpoints for:
- Balances (/cosmos.bank.v1beta1.Query/BalanceCopy /cosmos.bank.v1beta1.Query/Balance)
- Supply (/cosmos.bank.v1beta1.Query/TotalSupplyCopy /cosmos.bank.v1beta1.Query/TotalSupply)
- Denom metadata and send-enabled flags
These services reflect post-tax balances because taxes are deducted before bank writes occur.