nTbill Vault

Contract Addresses & Configuration

// nTBILL vault addresses (same on both Plume and Eth chains)
const VAULT_ADDRESS = "0xe72fe64840f4ef80e3ec73a1c749491b5c938cb9"
const TELLER_ADDRESS = "0x1492062b3ae7996c71f87a2b390b6b82afea0c59"
const ACCOUNTANT_ADDRESS = "0x0b738cd187872b265a689e8e4130c336e76892ec"

const INFRA = {
  predicateProxyAddress: "0x6104fe10ca937a086ba7AdbD0910A4733d380cB6",
  nativeFeeTokenAddress: "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE",
  bridgeMessageGas: 100000,
}

const PLUME_MAINNET = {
  chainId: 98866,
  layerZeroEndpointId: 30370,
  atomicQueueAddress: "0x220dc6d4569c1f406d532f9633d5be5bc86e8264",
  depositToken: {
    address: "0xdddd73f5df1f0dc31373357beac77545dc5a6f3f",
    decimals: 6,
    symbol: "pUSD",
    defaultSlippagePercentage: 0.005,
  }
}

const ETH_MAINNET = {
  chainId: 1,
  layerZeroEndpointId: 30101,
  atomicQueueAddress: "0x220dc6d4569c1f406d532f9633d5be5bc86e8264",
  depositToken: {
    address: "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
    decimals: 6,
    symbol: "USDC",
    defaultSlippagePercentage: 0.005,
  }
}

const VAULT_DECIMALS = 6
const PUSD_ADDRESS = PLUME_MAINNET.depositToken.address
const USDC_ADDRESS = ETH_MAINNET.depositToken.address
const PLUME_ATOMIC_QUEUE_ADDRESS = PLUME_MAINNET.atomicQueueAddress
const ETH_ATOMIC_QUEUE_ADDRESS = ETH_MAINNET.atomicQueueAddress

---

Summary: 6 Distinct Paths

Deposits (3 paths)

• USDC Ethereum -> nTBILL Plume (cross-chain deposit): 6 operations (compliance check, get exchange rate, compute minimumMint with slippage, calculate bridge fee, approve USDC, deposit & bridge)

• pUSD Plume -> nTBILL Plume (same-chain deposit): 5 operations (compliance check, get exchange rate, compute minimumMint, approve pUSD, direct deposit)

• USDC Ethereum -> nTBILL Ethereum (same-chain deposit): 5 operations (compliance check, get exchange rate, compute minimumMint, approve USDC, direct deposit)

Redemptions (3 paths)

• nTBILL Plume -> USDC Ethereum (cross-chain redemption): 7 operations (preview bridge fee, bridge shares, get exchange rate, compute atomicPrice with slippage, approve nTBILL, create withdrawal request, monitor withdrawal)

• nTBILL Plume -> pUSD Plume (same-chain redemption): 5 operations (get exchange rate, compute atomicPrice, approve nTBILL, create withdrawal request, monitor withdrawal)

• nTBILL Ethereum -> USDC Ethereum (same-chain redemption): 5 operations (get exchange rate, compute atomicPrice, approve nTBILL, create withdrawal request, monitor withdrawal)

---

DEPOSIT FLOWS

Path 1: Ethereum -> Plume (Cross-Chain Deposit)

1

Compliance Check (isDepositAndBridge=true)

GET https://api.nest.credit/v1/user/{userAddress}/compliance?chainId=1&isDepositAndBridge=true

Response: { data: { isCompliant: boolean, predicateMessage: {...} } }

2

Exchange Rate Query

// Call accountant on Ethereum
Accountant(ACCOUNTANT_ADDRESS).getRateInQuoteSafe(USDC_ADDRESS) -> rateInQuote
// Returns rate in USDC decimals (6), e.g., 1050000 = 1.05 USDC per nTBILL share

3

Calculate Minimum Mint

// Step 3a: Calculate expected vault shares
const oneShare = 10n ** BigInt(VAULT_DECIMALS) // 10^6 = 1000000n
const exchangeAmount = (depositAmount * oneShare) / rateInQuote

// Step 3b: Apply slippage protection
const slippageFactor = 1 - ETH_MAINNET.depositToken.defaultSlippagePercentage // 0.995
const slippageBigInt = BigInt(Math.floor(slippageFactor * 1e6)) // 995000n
const minimumMint = (exchangeAmount * slippageBigInt) / 1_000_000n

// Example: 1000 USDC deposit with 1.05 rate and 0.5% slippage
// exchangeAmount = (1000000000n * 1000000n) / 1050000n = 952380952n
// minimumMint = (952380952n * 995000n) / 1000000n = 947619047n

4

Calculate Bridge Fee

// Call teller to preview LayerZero bridge fee using expected share amount
const bridgeData = {
  chainSelector: PLUME_MAINNET.layerZeroEndpointId,
  destinationChainReceiver: userAddress,
  bridgeFeeToken: INFRA.nativeFeeTokenAddress,
  messageGas: INFRA.bridgeMessageGas,
  data: "0x"
}
Teller(TELLER_ADDRESS).previewFee(exchangeAmount, bridgeData) -> bridgeFee

5

Token Approval

// Approve USDC to predicate proxy on Ethereum
USDC.approve(INFRA.predicateProxyAddress, depositAmount)

6

Cross-Chain Deposit

// Execute deposit and bridge transaction on Ethereum
PredicateProxy(INFRA.predicateProxyAddress).depositAndBridge(
  USDC_ADDRESS,
  depositAmount,
  minimumMint,
  bridgeData,
  TELLER_ADDRESS,
  predicateMessage
) { value: bridgeFee }

Result: USDC deposited on Ethereum, nTBILL minted on Plume

---

Path 2: Plume -> Plume (Same-Chain Deposit)

1

Compliance Check

GET https://api.nest.credit/v1/user/{userAddress}/compliance?chainId=98866&isDepositAndBridge=false

Response: { data: { isCompliant: boolean, predicateMessage: {...} } }

2

Exchange Rate Query

// Call accountant on Plume
Accountant(ACCOUNTANT_ADDRESS).getRateInQuoteSafe(PUSD_ADDRESS) -> rateInQuote
// Returns rate in pUSD decimals (6), e.g., 1050000 = 1.05 pUSD per nTBILL share

3

Calculate Minimum Mint

// Step 3a: Calculate expected vault shares
const oneShare = 10n ** BigInt(VAULT_DECIMALS) // 10^6 = 1000000n
const exchangeAmount = (depositAmount * oneShare) / rateInQuote

// Step 3b: Apply slippage protection
const slippageFactor = 1 - PLUME_MAINNET.depositToken.defaultSlippagePercentage // 0.995
const slippageBigInt = BigInt(Math.floor(slippageFactor * 1e6)) // 995000n
const minimumMint = (exchangeAmount * slippageBigInt) / 1_000_000n

4

Token Approval

// Approve pUSD to predicate proxy on Plume
pUSD.approve(INFRA.predicateProxyAddress, depositAmount)

5

Direct Deposit

// Execute direct deposit on Plume
PredicateProxy(INFRA.predicateProxyAddress).deposit(
  PUSD_ADDRESS,
  depositAmount,
  minimumMint,
  userAddress,
  TELLER_ADDRESS,
  predicateMessage
)

Result: pUSD deposited on Plume, nTBILL minted on Plume

---

Path 3: Ethereum -> Ethereum (Same-Chain Deposit)

1

Compliance Check

GET https://api.nest.credit/v1/user/{userAddress}/compliance?chainId=1&isDepositAndBridge=false

Response: { data: { isCompliant: boolean, predicateMessage: {...} } }

2

Exchange Rate Query

// Call accountant on Ethereum
Accountant(ACCOUNTANT_ADDRESS).getRateInQuoteSafe(USDC_ADDRESS) -> rateInQuote
// Returns rate in USDC decimals (6), e.g., 1050000 = 1.05 USDC per nTBILL share

3

Calculate Minimum Mint

// Step 3a: Calculate expected vault shares
const oneShare = 10n ** BigInt(VAULT_DECIMALS) // 10^6 = 1000000n
const exchangeAmount = (depositAmount * oneShare) / rateInQuote

// Step 3b: Apply slippage protection
const slippageFactor = 1 - ETH_MAINNET.depositToken.defaultSlippagePercentage // 0.995
const slippageBigInt = BigInt(Math.floor(slippageFactor * 1e6)) // 995000n
const minimumMint = (exchangeAmount * slippageBigInt) / 1_000_000n

4

Token Approval

// Approve USDC to predicate proxy on Ethereum
USDC.approve(INFRA.predicateProxyAddress, depositAmount)

5

Direct Deposit

// Execute direct deposit on Ethereum
PredicateProxy(INFRA.predicateProxyAddress).deposit(
  USDC_ADDRESS,
  depositAmount,
  minimumMint,
  userAddress,
  TELLER_ADDRESS,
  predicateMessage
)

Result: USDC deposited on Ethereum, nTBILL minted on Ethereum

---

REDEMPTION FLOWS

Path 1: Plume -> Ethereum (Cross-Chain Redemption)

1

Preview Bridge Fee

// Quote the Plume -> Ethereum share bridge fee
const bridgeData = {
  chainSelector: ETH_MAINNET.layerZeroEndpointId,
  destinationChainReceiver: userAddress,
  bridgeFeeToken: INFRA.nativeFeeTokenAddress,
  messageGas: INFRA.bridgeMessageGas,
  data: "0x"
}
Teller(TELLER_ADDRESS).previewFee(shareAmount, bridgeData) -> bridgeFee

2

Bridge Shares to Ethereum

// Bridge nTBILL shares from Plume to Ethereum
Teller(TELLER_ADDRESS).bridge(
  shareAmount,
  bridgeData
) { value: bridgeFee }

3

Exchange Rate Query for Withdrawal

// After the bridge completes, get the current exchange rate on Ethereum
Accountant(ACCOUNTANT_ADDRESS).getRateInQuoteSafe(USDC_ADDRESS) -> rateInQuote

4

Calculate Atomic Price with Slippage

// Calculate atomic price (exchange rate with slippage protection)
const slippageFactor = 1 - ETH_MAINNET.depositToken.defaultSlippagePercentage // 0.995
const slippageBigInt = BigInt(Math.floor(slippageFactor * 1e6)) // 995000n
const atomicPrice = (rateInQuote * slippageBigInt) / 1_000_000n

// Example: If rate is 1050000 (1.05 USDC per share) with 0.5% slippage
// atomicPrice = (1050000n * 995000n) / 1000000n = 1044750n

5

Vault Token Approval

// Approve nTBILL shares to the Ethereum atomic queue
nTBILL.approve(ETH_ATOMIC_QUEUE_ADDRESS, shareAmount)

6

Create Cross-Chain Withdrawal Request

// Create atomic request for USDC on Ethereum
AtomicQueue(ETH_ATOMIC_QUEUE_ADDRESS).updateAtomicRequest(
  VAULT_ADDRESS,
  USDC_ADDRESS,
  {
    deadline: timestamp + (10 * 24 * 60 * 60),
    atomicPrice: atomicPrice,
    offerAmount: shareAmount,
    inSolve: false
  }
)

7

Monitor Cross-Chain Withdrawal

GET https://api.nest.credit/v1/vaults/nest-treasury-vault/pending-redemptions?chainId=1&user={userAddress}

Result: nTBILL bridged from Plume to Ethereum, then queued for USDC redemption on Ethereum

---

Path 2: Plume -> Plume (Same-Chain Redemption)

1

Exchange Rate Query for Withdrawal

// Get current exchange rate on Plume
Accountant(ACCOUNTANT_ADDRESS).getRateInQuoteSafe(PUSD_ADDRESS) -> rateInQuote

2

Calculate Atomic Price with Slippage

// Calculate atomic price (exchange rate with slippage protection)
const slippageFactor = 1 - PLUME_MAINNET.depositToken.defaultSlippagePercentage // 0.995
const slippageBigInt = BigInt(Math.floor(slippageFactor * 1e6)) // 995000n
const atomicPrice = (rateInQuote * slippageBigInt) / 1_000_000n

3

Vault Token Approval

// Approve nTBILL shares to the Plume atomic queue
nTBILL.approve(PLUME_ATOMIC_QUEUE_ADDRESS, shareAmount)

4

Create Same-Chain Withdrawal Request

// Create atomic request for pUSD on Plume
AtomicQueue(PLUME_ATOMIC_QUEUE_ADDRESS).updateAtomicRequest(
  VAULT_ADDRESS,
  PUSD_ADDRESS,
  {
    deadline: timestamp + (10 * 24 * 60 * 60),
    atomicPrice: atomicPrice,
    offerAmount: shareAmount,
    inSolve: false
  }
)

5

Monitor Same-Chain Withdrawal

GET https://api.nest.credit/v1/vaults/nest-treasury-vault/pending-redemptions?chainId=98866&user={userAddress}

Result: nTBILL queued for pUSD redemption on Plume

---

Path 3: Ethereum -> Ethereum (Same-Chain Redemption)

1

Exchange Rate Query for Withdrawal

// Get current exchange rate on Ethereum
Accountant(ACCOUNTANT_ADDRESS).getRateInQuoteSafe(USDC_ADDRESS) -> rateInQuote

2

Calculate Atomic Price with Slippage

// Calculate atomic price (exchange rate with slippage protection)
const slippageFactor = 1 - ETH_MAINNET.depositToken.defaultSlippagePercentage // 0.995
const slippageBigInt = BigInt(Math.floor(slippageFactor * 1e6)) // 995000n
const atomicPrice = (rateInQuote * slippageBigInt) / 1_000_000n

3

Vault Token Approval

// Approve nTBILL shares to the Ethereum atomic queue
nTBILL.approve(ETH_ATOMIC_QUEUE_ADDRESS, shareAmount)

4

Create Same-Chain Withdrawal Request

// Create atomic request for USDC on Ethereum
AtomicQueue(ETH_ATOMIC_QUEUE_ADDRESS).updateAtomicRequest(
  VAULT_ADDRESS,
  USDC_ADDRESS,
  {
    deadline: timestamp + (10 * 24 * 60 * 60),
    atomicPrice: atomicPrice,
    offerAmount: shareAmount,
    inSolve: false
  }
)

5

Monitor Same-Chain Withdrawal

GET https://api.nest.credit/v1/vaults/nest-treasury-vault/pending-redemptions?chainId=1&user={userAddress}

Result: nTBILL queued for USDC redemption on Ethereum

---

Key Calculation Formulas

Minimum Mint (Deposits):

const oneShare = 10n ** BigInt(VAULT_DECIMALS)
const exchangeAmount = (depositAmount * oneShare) / rateInQuote
const slippageMultiplier = BigInt(Math.floor((1 - slippagePercentage) * 1e6))
const minimumMint = (exchangeAmount * slippageMultiplier) / 1_000_000n

Atomic Price (Withdrawals):

const slippageMultiplier = BigInt(Math.floor((1 - slippagePercentage) * 1e6))
const atomicPrice = (rateInQuote * slippageMultiplier) / 1_000_000n

Both pUSD on Plume and USDC on Ethereum use 6-decimal quote units in this guide.