VariableDebtToken

The VariableDebtToken.sol contract represents the debt owed by users who have borrowed assets from the HypurrFi protocol at a variable interest rate. The token balance represents the user’s debt that continuously increases based on the variable interest rate.

Debt tokens are non-transferrable tokens that track a user’s debt position in the protocol. Each token is specific to an underlying asset and accrues interest based on the current variable interest rate of that asset.

Write Methods

mint

function mint(
    address user,
    address onBehalfOf,
    uint256 amount,
    uint256 index
) external returns (bool, uint256)

Mints debt tokens to track a new borrow position.

Call Params

Name	Type	Description
user	address	The address performing the mint
onBehalfOf	address	The address receiving the minted tokens
amount	uint256	The amount of tokens to mint
index	uint256	The variable debt index of the reserve

Return Values

Type	Description
bool	True if the previous balance of the user was 0
uint256	The scaled total supply after minting

burn

function burn(
    address from,
    uint256 amount,
    uint256 index
) external returns (uint256)

Burns debt tokens when a user repays their debt.

Call Params

Name	Type	Description
from	address	The address from which to burn tokens
amount	uint256	The amount to burn
index	uint256	The variable debt index of the reserve

Return Values

Type	Description
uint256	The scaled total supply after burning

approveDelegation

function approveDelegation(
    address delegatee,
    uint256 amount
) external

Approves a delegatee to borrow a specific amount on behalf of the delegator.

Call Params

Name	Type	Description
delegatee	address	The address authorized to borrow
amount	uint256	The amount the delegatee is authorized to borrow

View Methods

borrowAllowance

function borrowAllowance(
    address fromUser,
    address toUser
) external view returns (uint256)

Returns the borrow allowance of toUser on behalf of fromUser.

Call Params

Name	Type	Description
fromUser	address	The user granting borrowing rights
toUser	address	The user being granted borrowing rights

Return Values

Type	Description
uint256	The current borrow allowance

UNDERLYING_ASSET_ADDRESS

function UNDERLYING_ASSET_ADDRESS() external view returns (address)

Returns the address of the underlying asset of this debt token.

Return Values

Type	Description
address	The address of the underlying asset

POOL

function POOL() external view returns (address)

Returns the address of the lending pool where this debt token is used.

Return Values

Type	Description
address	The address of the lending pool

Events

Mint

event Mint(
    address indexed caller,
    address indexed onBehalfOf,
    uint256 value,
    uint256 balanceIncrease,
    uint256 index
)

Emitted when debt tokens are minted.

Burn

event Burn(
    address indexed from,
    address indexed target,
    uint256 value,
    uint256 balanceIncrease,
    uint256 index
)

Emitted when debt tokens are burned.

BorrowAllowanceDelegated

event BorrowAllowanceDelegated(
    address indexed fromUser,
    address indexed toUser,
    address indexed asset,
    uint256 amount
)

Emitted when borrow allowance is delegated.

Usage Example

// Approve delegation for borrowing
variableDebtToken.approveDelegation(delegatee, 1000);

// Borrow assets through delegation
pool.borrow(asset, 1000, VARIABLE_RATE, 0, delegator);

// Repay borrowed assets
pool.repay(asset, 1000, VARIABLE_RATE, onBehalfOf);

Security Considerations

Variable Debt Tokens cannot be transferred between accounts
Only the HypurrFi Pool contract can mint or burn tokens
Delegation approvals should be managed carefully
Interest accrual is continuous based on the variable rate

ABI

[
  {
    "type": "constructor",
    "inputs": [
      {
        "name": "pool",
        "type": "address",
        "internalType": "contract IPool"
      }
    ],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "DEBT_TOKEN_REVISION",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "DELEGATION_WITH_SIG_TYPEHASH",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "bytes32",
        "internalType": "bytes32"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "DOMAIN_SEPARATOR",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "bytes32",
        "internalType": "bytes32"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "EIP712_REVISION",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "bytes",
        "internalType": "bytes"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "POOL",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "address",
        "internalType": "contract IPool"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "UNDERLYING_ASSET_ADDRESS",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "address",
        "internalType": "address"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "allowance",
    "inputs": [
      {
        "name": "",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "",
        "type": "address",
        "internalType": "address"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "approve",
    "inputs": [
      {
        "name": "",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "bool",
        "internalType": "bool"
      }
    ],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "approveDelegation",
    "inputs": [
      {
        "name": "delegatee",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "amount",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "outputs": [],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "balanceOf",
    "inputs": [
      {
        "name": "user",
        "type": "address",
        "internalType": "address"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "borrowAllowance",
    "inputs": [
      {
        "name": "fromUser",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "toUser",
        "type": "address",
        "internalType": "address"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "burn",
    "inputs": [
      {
        "name": "from",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "amount",
        "type": "uint256",
        "internalType": "uint256"
      },
      {
        "name": "index",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "decimals",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "uint8",
        "internalType": "uint8"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "decreaseAllowance",
    "inputs": [
      {
        "name": "",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "bool",
        "internalType": "bool"
      }
    ],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "delegationWithSig",
    "inputs": [
      {
        "name": "delegator",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "delegatee",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "value",
        "type": "uint256",
        "internalType": "uint256"
      },
      {
        "name": "deadline",
        "type": "uint256",
        "internalType": "uint256"
      },
      {
        "name": "v",
        "type": "uint8",
        "internalType": "uint8"
      },
      {
        "name": "r",
        "type": "bytes32",
        "internalType": "bytes32"
      },
      {
        "name": "s",
        "type": "bytes32",
        "internalType": "bytes32"
      }
    ],
    "outputs": [],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "getIncentivesController",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "address",
        "internalType": "contract IAaveIncentivesController"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "getPreviousIndex",
    "inputs": [
      {
        "name": "user",
        "type": "address",
        "internalType": "address"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "getScaledUserBalanceAndSupply",
    "inputs": [
      {
        "name": "user",
        "type": "address",
        "internalType": "address"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      },
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "increaseAllowance",
    "inputs": [
      {
        "name": "",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "bool",
        "internalType": "bool"
      }
    ],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "initialize",
    "inputs": [
      {
        "name": "initializingPool",
        "type": "address",
        "internalType": "contract IPool"
      },
      {
        "name": "underlyingAsset",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "incentivesController",
        "type": "address",
        "internalType": "contract IAaveIncentivesController"
      },
      {
        "name": "debtTokenDecimals",
        "type": "uint8",
        "internalType": "uint8"
      },
      {
        "name": "debtTokenName",
        "type": "string",
        "internalType": "string"
      },
      {
        "name": "debtTokenSymbol",
        "type": "string",
        "internalType": "string"
      },
      {
        "name": "params",
        "type": "bytes",
        "internalType": "bytes"
      }
    ],
    "outputs": [],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "mint",
    "inputs": [
      {
        "name": "user",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "onBehalfOf",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "amount",
        "type": "uint256",
        "internalType": "uint256"
      },
      {
        "name": "index",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "bool",
        "internalType": "bool"
      },
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "name",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "string",
        "internalType": "string"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "nonces",
    "inputs": [
      {
        "name": "owner",
        "type": "address",
        "internalType": "address"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "scaledBalanceOf",
    "inputs": [
      {
        "name": "user",
        "type": "address",
        "internalType": "address"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "scaledTotalSupply",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "setIncentivesController",
    "inputs": [
      {
        "name": "controller",
        "type": "address",
        "internalType": "contract IAaveIncentivesController"
      }
    ],
    "outputs": [],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "symbol",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "string",
        "internalType": "string"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "totalSupply",
    "inputs": [],
    "outputs": [
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "stateMutability": "view"
  },
  {
    "type": "function",
    "name": "transfer",
    "inputs": [
      {
        "name": "",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "bool",
        "internalType": "bool"
      }
    ],
    "stateMutability": "nonpayable"
  },
  {
    "type": "function",
    "name": "transferFrom",
    "inputs": [
      {
        "name": "",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "",
        "type": "address",
        "internalType": "address"
      },
      {
        "name": "",
        "type": "uint256",
        "internalType": "uint256"
      }
    ],
    "outputs": [
      {
        "name": "",
        "type": "bool",
        "internalType": "bool"
      }
    ],
    "stateMutability": "nonpayable"
  },
  {
    "type": "event",
    "name": "Approval",
    "inputs": [
      {
        "name": "owner",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "spender",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "value",
        "type": "uint256",
        "indexed": false,
        "internalType": "uint256"
      }
    ],
    "anonymous": false
  },
  {
    "type": "event",
    "name": "BorrowAllowanceDelegated",
    "inputs": [
      {
        "name": "fromUser",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "toUser",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "asset",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "amount",
        "type": "uint256",
        "indexed": false,
        "internalType": "uint256"
      }
    ],
    "anonymous": false
  },
  {
    "type": "event",
    "name": "Burn",
    "inputs": [
      {
        "name": "from",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "target",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "value",
        "type": "uint256",
        "indexed": false,
        "internalType": "uint256"
      },
      {
        "name": "balanceIncrease",
        "type": "uint256",
        "indexed": false,
        "internalType": "uint256"
      },
      {
        "name": "index",
        "type": "uint256",
        "indexed": false,
        "internalType": "uint256"
      }
    ],
    "anonymous": false
  },
  {
    "type": "event",
    "name": "Initialized",
    "inputs": [
      {
        "name": "underlyingAsset",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "pool",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "incentivesController",
        "type": "address",
        "indexed": false,
        "internalType": "address"
      },
      {
        "name": "debtTokenDecimals",
        "type": "uint8",
        "indexed": false,
        "internalType": "uint8"
      },
      {
        "name": "debtTokenName",
        "type": "string",
        "indexed": false,
        "internalType": "string"
      },
      {
        "name": "debtTokenSymbol",
        "type": "string",
        "indexed": false,
        "internalType": "string"
      },
      {
        "name": "params",
        "type": "bytes",
        "indexed": false,
        "internalType": "bytes"
      }
    ],
    "anonymous": false
  },
  {
    "type": "event",
    "name": "Mint",
    "inputs": [
      {
        "name": "caller",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "onBehalfOf",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "value",
        "type": "uint256",
        "indexed": false,
        "internalType": "uint256"
      },
      {
        "name": "balanceIncrease",
        "type": "uint256",
        "indexed": false,
        "internalType": "uint256"
      },
      {
        "name": "index",
        "type": "uint256",
        "indexed": false,
        "internalType": "uint256"
      }
    ],
    "anonymous": false
  },
  {
    "type": "event",
    "name": "Transfer",
    "inputs": [
      {
        "name": "from",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "to",
        "type": "address",
        "indexed": true,
        "internalType": "address"
      },
      {
        "name": "value",
        "type": "uint256",
        "indexed": false,
        "internalType": "uint256"
      }
    ],
    "anonymous": false
  }
]

Introduction

Concepts

Primitives

Developers

Points

Staking

VariableDebtToken

Write Methods

mint

burn

approveDelegation

View Methods

borrowAllowance

UNDERLYING_ASSET_ADDRESS

POOL

Events

Mint

Burn

BorrowAllowanceDelegated

Usage Example

Security Considerations

ABI

Introduction

Concepts

Primitives

Developers

Points

Staking

​Write Methods

​mint

​burn

​approveDelegation

​View Methods

​borrowAllowance

​UNDERLYING_ASSET_ADDRESS

​POOL

​Events

​Mint

​Burn

​BorrowAllowanceDelegated

​Usage Example

​Security Considerations

​ABI

Write Methods

mint

burn

approveDelegation

View Methods

borrowAllowance

UNDERLYING_ASSET_ADDRESS

POOL

Events

Mint

Burn

BorrowAllowanceDelegated

Usage Example

Security Considerations

ABI