Flash Loan

The Flash Loan module provides uncollateralized borrowing functionality, allowing users to borrow and repay assets in the same transaction, primarily used for arbitrage, debt restructuring, and other scenarios.

Core Concepts

Flash Loan Principle

Flash loans allow users to borrow assets without collateral, but must meet the following conditions:

Same Transaction: Borrowing and repayment must be completed in the same transaction
Complete Repayment: Must repay the full borrowed amount plus fees
Atomicity: If repayment fails, the entire transaction will be rolled back

Use Cases

Arbitrage Trading: Price arbitrage between different DEXs
Debt Restructuring: Optimize borrowing portfolios to reduce interest rates
Liquidation Protection: Quickly replenish collateral to avoid liquidation
Liquidity Management: Temporarily obtain liquidity for other operations

API Reference

getAllFlashLoanAssets

Get all available flash loan assets from the API. Uses caching to avoid repeated API calls. See documentation for details.

Usage Example

import { getAllFlashLoanAssets } from '@naviprotocol/lending'

const flashLoanAssets = await getAllFlashLoanAssets({
  env: 'prod',
  cacheTime: 30000
})

Result Example

[
  {
    "max": "50000000000",
    "min": "0",
    "assetId": 3,
    "poolId": "0x71b9f6e822c48ce827bceadce82201d6a7559f7b0350ed1daa1dc2ba3ac41b56",
    "supplierFee": 0,
    "flashloanFee": 0.0006,
    "coinType": "0xaf8cd5edc19c4512f4259f0bee101a40d41ebed738ade5874359610ef8eeced5::coin::COIN"
  }
]

getFlashLoanAsset

Get a specific flash loan asset by identifier. See documentation for details.

Usage Example

import { getFlashLoanAsset, getPool } from '@naviprotocol/lending'

// Get by coin type
const assetByCoinType = await getFlashLoanAsset('0x2::sui::SUI')

// Get by asset ID
const assetById = await getFlashLoanAsset(0)

// Get by pool
const pool = await getPool('0x2::sui::SUI')
const assetByObject = await getFlashLoanAsset(pool)

Result Example

{
  "max": "5000000000",
  "min": "0",
  "assetId": 0,
  "poolId": "0x96df0fce3c471489f4debaaa762cf960b3d97820bd1f3f025ff8190730e958c5",
  "supplierFee": 0,
  "flashloanFee": 0.0006,
  "coinType": "0x0000000000000000000000000000000000000000000000000000000000000002::sui::SUI"
}

flashloanPTB

Create a flash loan transaction in the PTB (Programmable Transaction Block). This function initiates a flash loan by borrowing the specified amount of assets. The borrowed assets must be repaid within the same transaction using repayFlashLoanPTB. See documentation for details.

Usage Example

import { flashloanPTB } from '@naviprotocol/lending'
import { Transaction } from '@mysten/sui/transactions'

const tx = new Transaction()

const [balance, receipt] = await flashloanPTB(
  tx,
  '0x2::sui::SUI', // Asset identifier
  1000000000, // Amount to borrow
  { env: 'prod' }
)

repayFlashLoanPTB

Repay a flash loan transaction in the PTB. This function repays the flash loan using the receipt from the original flash loan and the coin object containing the repayment amount. See documentation for details.

Usage Example

import { repayFlashLoanPTB } from '@naviprotocol/lending'
import { Transaction } from '@mysten/sui/transactions'

const tx = new Transaction()

const [balance] = await repayFlashLoanPTB(
  tx,
  '0x2::sui::SUI', // Asset identifier
  receipt, // Receipt from original flash loan
  coinObject, // Coin object containing repayment amount
  { env: 'prod' }
)

Complete Flash Loan Example

Here's a complete example of how to use flash loans for arbitrage:

import { flashloanPTB, repayFlashLoanPTB } from '@naviprotocol/lending'
import { Transaction } from '@mysten/sui/transactions'

async function executeFlashLoanArbitrage() {
  const tx = new Transaction()

  // Step 1: Initiate flash loan
  const [borrowedBalance, receipt] = await flashloanPTB(
    tx,
    '0x2::sui::SUI',
    1000000000, // 1 SUI
    { env: 'prod' }
  )

  // Step 2: Execute arbitrage logic with borrowed funds
  // ... your arbitrage trading logic here ...

  // Step 3: Repay the flash loan
  const [remainingBalance] = await repayFlashLoanPTB(
    tx,
    '0x2::sui::SUI',
    receipt,
    borrowedBalance,
    { env: 'prod' }
  )

  // Step 4: Execute the transaction
  ...
}

Important Notes

Transaction Atomicity: Flash loans must be completed within a single transaction. If any part fails, the entire transaction is rolled back.
Fee Calculation: Flash loans incur fees that must be included in the repayment amount.
Pool Support: Not all pools support flash loans. Always check if the pool supports flash loans before attempting to use them.
Amount Limits: Each asset has a maximum flash loan amount. Exceeding this limit will cause the transaction to fail.

Flash Loan

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