Vaults
Vaults are used to earn rewards. Tokens such as imUSD or Feeder Pool tokens can be deposited to earn additional MTA rewards. On Polygon the contract HeadlessRewardToken is used. This allows for accrual of 2 Rewards and does not contain the Boost functionality that is present on Ethereum Mainnet. Contracts are upgradable.
The Feeder Pool Vault for mUSD/FRAX has been developed by frax.finance and is not part of these docs.
The following table lays out the currently deployed vaults and what contract is used.
Polygon
Vault
Address
mUSD/FRAX Feeder Pool Vault (FRAX Contract)

imUSD Vault

stake()

function stake (uint256 _amount) external
Stakes a given amount of the StakingToken for the sender
Parameter
Type
Description
_amount
uint256
Units of StakingToken

stake()

function stake (address _beneficiary, uint256 _amount) external
Stakes a given amount of the StakingToken for a given beneficiary
Parameter
Type
Description
_beneficiary
address
Staked tokens are credited to this address
_amount
uint256
Units of StakingToken

exit()

function exit () external
Withdraws stake from pool and claims any rewards

withdraw()

function withdraw (uint256 _amount) external
Withdraws given stake amount from the pool

withdrawAndUnwrap()

function withdrawAndUnwrap (uint256 _amount, uint256 _minAmountOut, address _output, address _beneficiary, address _router, bool _isBassetOut) external returns (uint256 outputQuantity)
Redeems staked interest-bearing asset tokens for either bAsset or fAsset tokens. Withdraws a given staked amount of interest-bearing assets from the vault, redeems the interest-bearing asset for the underlying mAsset and either
  1. 1.
    Redeems the underlying mAsset tokens for bAsset tokens.
  2. 2.
    Swaps the underlying mAsset tokens for fAsset tokens in a Feeder Pool.
Parameter
Type
Description
_amount
uint256
Units of the staked interest-bearing asset tokens to withdraw. eg imUSD or imBTC.
_minAmountOut
uint256
Minimum units of output tokens to be received by the beneficiary. This is to the same decimal places as the output token.
_output
address
Asset to receive in exchange for the redeemed mAssets. This can be a bAsset or a fAsset. For example: - bAssets (USDC, DAI, sUSD or USDT) or fAssets (GUSD, BUSD, alUSD, FEI or RAI) for mainnet imUSD Vault.
- bAssets (USDC, DAI or USDT) or fAsset FRAX for Polygon imUSD Vault.
- bAssets (WBTC, sBTC or renBTC) or fAssets (HBTC or TBTCV2) for mainnet imBTC Vault.|
_beneficiary
address
Address to send output tokens to.
_router
address
mAsset address if the output is a bAsset. Feeder Pool address if the output is a fAsset.
_isBassetOut
bool
true if output is a bAsset. false if output is a fAsset

claimReward()

function claimReward () external
Claims outstanding rewards (both platform and native) for the sender. First updates outstanding reward allocation and then transfers.

claimRewardOnly()

function claimRewardOnly () external
Claims outstanding rewards for the sender. Only the native rewards token, and not the platform rewards

getRewardToken()

function getRewardToken () external returns (contract IERC20)
Gets the RewardsToken

getPlatformToken()

function getPlatformToken () external returns (contract IERC20)
Gets the PlatformToken

lastTimeRewardApplicable()

function lastTimeRewardApplicable () public returns (uint256)
Gets the last applicable timestamp for this reward period

rewardPerToken()

function rewardPerToken () public returns (uint256, uint256)
Calculates the amount of unclaimed rewards a user has earned

earned()

function earned (address _account) public returns (uint256, uint256)
Calculates the amount of unclaimed rewards a user has earned
Parameter
Type
Description
_account
address
User address

notifyRewardAmount()

function notifyRewardAmount (uint256 _reward) external
Notifies the contract that new rewards have been added. Calculates an updated rewardRate based on the rewards in period.
Parameter
Type
Description
_reward
uint256
Units of RewardToken that have been added to the pool

totalSupply()

function totalSupply () public returns (uint256)
Get the total amount of the staked token

balanceOf()

function balanceOf (address _account) public returns (uint256)
Get the balance of a given account
Parameter
Type
Description
_account
address
User for which to retrieve balance