> ## Documentation Index
> Fetch the complete documentation index at: https://docs.stable.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Bank precompile reference

> Bank precompile reference: ERC-20 methods, mint/burn authorization, and event signatures.

<Note>
  **Concept:** For what the bank module does and when to use it, see [Bank module](/en/explanation/bank-module).
</Note>

## Abstract

The `x/bank` module in Stable SDK only provides basic token management features.
You can transfer any token to any account without restriction, but you cannot delegate another account to transfer your tokens.
For these reasons, the `bank` precompiled contract offers additional authorization and delegation features on top of the existing `x/bank` module in Stable SDK.

## Contents

1. **[Concepts](#concepts)**
2. **[Configuration](#configuration)**
3. **[Methods](#methods)**
4. **[Events](#events)**

## Concepts

This precompiled contract provides ERC-20 standard methods - such as `transfer` and `balanceOf` for transfer and `transferFrom`, `approve` and `allowance` for delegation. You can call these methods directly without registering the contract address.

However, the `x/precompile` module must whitelist and register the contract address before you can use the `mint` and `burn` methods.

```go theme={"dark"}
func (p *Precompile) mint(
  ctx sdk.Context,
  contract *vm.Contract,
  denom string,
  method *abi.Method,
  stateDB vm.StateDB,
  args []interface{},
) ([]byte, error) {
  // ...

  // mint method is only allowed for the registered caller contract
  if _, err := precompilecommon.CheckPermissions(ctx, p.precompileKeeper, contract.CallerAddress, CallerPermissions); err != nil {
    return nil, err
  }
```

This additional verification process guarantees that the token contract calling this precompiled contract is authorized.

To register a token contract address and its denom in the `x/precompile` module whitelist, you must submit a governance proposal.

## Configuration

The contract address and gas cost are predefined.

### Contract address

* `0x0000000000000000000000000000000000001003` for STABLE (governance token)

## Methods

### `mint`

Mints requested amount of new tokens and transfer to the account.
The amount of tokens to be minted must be greater than zero.

`PrecompiledBankMint` is emitted when the tokens are successfully minted and transferred to the account.

NOTE:

* Governance token minting is prohibited.
* Caller contracts calling the mint method must be registered in x/precompile module.

#### Inputs

| Name   | Type    | Description                              |
| ------ | ------- | ---------------------------------------- |
| to     | address | the address to receive the minted tokens |
| amount | uint256 | the amount of tokens to be minted        |

#### Outputs

| Name    | Type | Description                                                               |
| ------- | ---- | ------------------------------------------------------------------------- |
| success | bool | true if the tokens are successfully minted and transferred to the account |

### `burn`

Burns requested amount of tokens from the account.
The amount of tokens to be burned must be greater than zero.

`PrecompiledBankBurn` is emitted when the tokens are successfully burned.

NOTE:

* Burning governance token is prohibited.
* Caller contracts calling the burn method must be registered in x/precompile module.

#### Inputs

| Name   | Type    | Description                       |
| ------ | ------- | --------------------------------- |
| from   | address | the address to burn the tokens    |
| amount | uint256 | the amount of tokens to be burned |

#### Outputs

| Name    | Type | Description                                |
| ------- | ---- | ------------------------------------------ |
| success | bool | true if the tokens are successfully burned |

### `transfer`

Transfers requested amount of tokens from sender to the recipient.
Token must be set sendable. The amount of tokens to be transferred must be greater than zero.

`PrecompiledBankTransfer` is emitted when the tokens are successfully transferred.

#### Inputs

| Name   | Type    | Description                            |
| ------ | ------- | -------------------------------------- |
| to     | address | the address to receive the tokens      |
| amount | uint256 | the amount of tokens to be transferred |

#### Outputs

| Name    | Type | Description                                     |
| ------- | ---- | ----------------------------------------------- |
| success | bool | true if the tokens are successfully transferred |

### `transferFrom`

Transfers requested amount of tokens from owner to recipient by authorized spender within the limits of the allowance.
Token must be set sendable.
The amount of tokens to be transferred must be greater than zero and less than or equal to the current allowance.

`PrecompiledBankTransfer` is emitted when the tokens are successfully transferred.

#### Inputs

| Name   | Type    | Description                            |
| ------ | ------- | -------------------------------------- |
| from   | address | the address to transfer the tokens     |
| to     | address | the address to receive the tokens      |
| amount | uint256 | the amount of tokens to be transferred |

#### Outputs

| Name    | Type | Description                                     |
| ------- | ---- | ----------------------------------------------- |
| success | bool | true if the tokens are successfully transferred |

### `multiTransfer`

Transfers tokens from single account to multiple accounts.
Token must be set sendable.
The amount of tokens to be transferred to each recipient must be greater than zero.

`PrecompiledBankTransfer` is emitted per each recipient when the tokens are successfully transferred.

#### Inputs

| Name   | Type       | Description                                              |
| ------ | ---------- | -------------------------------------------------------- |
| to     | address\[] | the addresses to receive the transferred tokens          |
| amount | uint256\[] | the amount of tokens to be transferred to each recipient |

#### Outputs

| Name    | Type | Description                                                       |
| ------- | ---- | ----------------------------------------------------------------- |
| success | bool | true if the tokens are successfully transferred to each recipient |

### `approve`

Authorizes a spender to transfer tokens from the owner’s account.
The amount of tokens to be authorized must be greater than zero.

`PrecompiledBankApproval` is emitted when the authorization is successfully set.

#### Inputs

| Name    | Type    | Description                           |
| ------- | ------- | ------------------------------------- |
| spender | address | the address to authorize              |
| value   | uint256 | the amount of tokens to be authorized |

#### Outputs

| Name    | Type | Description                                   |
| ------- | ---- | --------------------------------------------- |
| success | bool | true if the authorization is successfully set |

### `revoke`

Revokes the authorization of spender for transferring tokens from owner.

`PrecompiledBankRevoke` is emitted when the authorization is successfully revoked.

#### Inputs

| Name    | Type    | Description           |
| ------- | ------- | --------------------- |
| spender | address | the address to revoke |

#### Outputs

| Name    | Type | Description                                       |
| ------- | ---- | ------------------------------------------------- |
| success | bool | true if the authorization is successfully revoked |

### `balanceOf`

Returns balance of tokens from the account.

#### Inputs

| Name    | Type    | Description                              |
| ------- | ------- | ---------------------------------------- |
| account | address | the address to get the balance of tokens |

#### Outputs

| Name    | Type    | Description                         |
| ------- | ------- | ----------------------------------- |
| balance | uint256 | the amount of tokens in the account |

### `totalSupply`

Returns total supply of tokens.

#### Inputs

none

#### Outputs

| Name        | Type    | Description                |
| ----------- | ------- | -------------------------- |
| totalSupply | uint256 | the total amount of tokens |

### `allowance`

Returns the amount which spender is still allowed to withdraw from owner.

#### Inputs

| Name    | Type    | Description                |
| ------- | ------- | -------------------------- |
| owner   | address | the address of the owner   |
| spender | address | the address of the spender |

#### Outputs

| Name   | Type    | Description                     |
| ------ | ------- | ------------------------------- |
| amount | uint256 | the amount of tokens authorized |

## Events

All events emitted from this precompiled contract are prefixed with `PrecompiledBank`.
To avoid ambiguity, token contract calling this precompiled contract should avoid using event names with the same prefix.

### PrecompiledBankMint

| Name   | Type    | Indexed | Description                              |
| ------ | ------- | ------- | ---------------------------------------- |
| from   | address | Y       | the address that minted the tokens       |
| to     | address | Y       | the address to receive the minted tokens |
| amount | uint256 | N       | the amount of tokens minted              |

### PrecompiledBankBurn

| Name   | Type    | Indexed | Description                        |
| ------ | ------- | ------- | ---------------------------------- |
| from   | address | Y       | the address that burned the tokens |
| to     | address | Y       | not used in this method            |
| amount | uint256 | N       | the amount of tokens burned        |

### PrecompiledBankTransfer

| Name   | Type    | Indexed | Description                                   |
| ------ | ------- | ------- | --------------------------------------------- |
| from   | address | Y       | the address that transferred the tokens       |
| to     | address | Y       | the address to receive the transferred tokens |
| amount | uint256 | N       | the amount of tokens transferred              |

### PrecompiledBankApproval

| Name    | Type    | Indexed | Description                            |
| ------- | ------- | ------- | -------------------------------------- |
| owner   | address | Y       | the address that authorized the tokens |
| spender | address | Y       | the address to authorize               |
| value   | uint256 | N       | the amount of tokens authorized        |

### PrecompiledBankRevoke

| Name    | Type    | Indexed | Description                         |
| ------- | ------- | ------- | ----------------------------------- |
| owner   | address | Y       | the address that revoked the tokens |
| spender | address | Y       | the address to revoke               |
| value   | uint256 | N       | the amount of tokens authorized     |