Arbitrage Bot: Price Discovery

index.js

require('dotenv').config()
const express = require('express')
const http = require('http')
const Web3 = require('web3')
const moment = require('moment-timezone')

// SERVER CONFIG
const PORT = process.env.PORT || 5000
const app = express();
const server = http.createServer(app).listen(PORT, () => console.log(`Listening on ${ PORT }`))

// WEB3 CONFIG
var web3 = new Web3(new Web3.providers.WebsocketProvider(process.env.RPC_URL_WS));

// Uniswap V3 Router Contract: https://etherscan.io/address/0xb27308f9F90D607463bb33eA1BeBb41C27CE5AB6#code
const UNISWAP_QUOTER_ABI = [{"inputs":[{"internalType":"address","name":"_factory","type":"address"},{"internalType":"address","name":"_WETH9","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"WETH9","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"factory","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"uint256","name":"amountIn","type":"uint256"}],"name":"quoteExactInput","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"name":"quoteExactInputSingle","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"uint256","name":"amountOut","type":"uint256"}],"name":"quoteExactOutput","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"name":"quoteExactOutputSingle","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"int256","name":"amount0Delta","type":"int256"},{"internalType":"int256","name":"amount1Delta","type":"int256"},{"internalType":"bytes","name":"path","type":"bytes"}],"name":"uniswapV3SwapCallback","outputs":[],"stateMutability":"view","type":"function"}]
const UNISWAP_QUOTER_ADDRESS = '0xb27308f9F90D607463bb33eA1BeBb41C27CE5AB6';
var uniswapRouter = new web3.eth.Contract(UNISWAP_QUOTER_ABI, UNISWAP_QUOTER_ADDRESS);

// Kyber mainnet proxy: https://etherscan.io/address/0x9AAb3f75489902f3a48495025729a0AF77d4b11e#readContract
const kyberNetProxyAddress = '0x9AAb3f75489902f3a48495025729a0AF77d4b11e';
const kyberNetProxyABI = [{"constant":false,"inputs":[{"name":"alerter","type":"address"}],"name":"removeAlerter","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"enabled","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"pendingAdmin","outputs":[{"name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"getOperators","outputs":[{"name":"","type":"address[]"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"src","type":"address"},{"name":"srcAmount","type":"uint256"},{"name":"dest","type":"address"},{"name":"destAddress","type":"address"},{"name":"maxDestAmount","type":"uint256"},{"name":"minConversionRate","type":"uint256"},{"name":"walletId","type":"address"},{"name":"hint","type":"bytes"}],"name":"tradeWithHint","outputs":[{"name":"","type":"uint256"}],"payable":true,"stateMutability":"payable","type":"function"},{"constant":false,"inputs":[{"name":"token","type":"address"},{"name":"srcAmount","type":"uint256"},{"name":"minConversionRate","type":"uint256"}],"name":"swapTokenToEther","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"token","type":"address"},{"name":"amount","type":"uint256"},{"name":"sendTo","type":"address"}],"name":"withdrawToken","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"maxGasPrice","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"newAlerter","type":"address"}],"name":"addAlerter","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"kyberNetworkContract","outputs":[{"name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"user","type":"address"}],"name":"getUserCapInWei","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"src","type":"address"},{"name":"srcAmount","type":"uint256"},{"name":"dest","type":"address"},{"name":"minConversionRate","type":"uint256"}],"name":"swapTokenToToken","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"newAdmin","type":"address"}],"name":"transferAdmin","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"claimAdmin","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"token","type":"address"},{"name":"minConversionRate","type":"uint256"}],"name":"swapEtherToToken","outputs":[{"name":"","type":"uint256"}],"payable":true,"stateMutability":"payable","type":"function"},{"constant":false,"inputs":[{"name":"newAdmin","type":"address"}],"name":"transferAdminQuickly","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"getAlerters","outputs":[{"name":"","type":"address[]"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"src","type":"address"},{"name":"dest","type":"address"},{"name":"srcQty","type":"uint256"}],"name":"getExpectedRate","outputs":[{"name":"expectedRate","type":"uint256"},{"name":"slippageRate","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"user","type":"address"},{"name":"token","type":"address"}],"name":"getUserCapInTokenWei","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"newOperator","type":"address"}],"name":"addOperator","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_kyberNetworkContract","type":"address"}],"name":"setKyberNetworkContract","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"operator","type":"address"}],"name":"removeOperator","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"field","type":"bytes32"}],"name":"info","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"src","type":"address"},{"name":"srcAmount","type":"uint256"},{"name":"dest","type":"address"},{"name":"destAddress","type":"address"},{"name":"maxDestAmount","type":"uint256"},{"name":"minConversionRate","type":"uint256"},{"name":"walletId","type":"address"}],"name":"trade","outputs":[{"name":"","type":"uint256"}],"payable":true,"stateMutability":"payable","type":"function"},{"constant":false,"inputs":[{"name":"amount","type":"uint256"},{"name":"sendTo","type":"address"}],"name":"withdrawEther","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"token","type":"address"},{"name":"user","type":"address"}],"name":"getBalance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"admin","outputs":[{"name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"inputs":[{"name":"_admin","type":"address"}],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"name":"trader","type":"address"},{"indexed":false,"name":"src","type":"address"},{"indexed":false,"name":"dest","type":"address"},{"indexed":false,"name":"actualSrcAmount","type":"uint256"},{"indexed":false,"name":"actualDestAmount","type":"uint256"}],"name":"ExecuteTrade","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"newNetworkContract","type":"address"},{"indexed":false,"name":"oldNetworkContract","type":"address"}],"name":"KyberNetworkSet","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"token","type":"address"},{"indexed":false,"name":"amount","type":"uint256"},{"indexed":false,"name":"sendTo","type":"address"}],"name":"TokenWithdraw","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"amount","type":"uint256"},{"indexed":false,"name":"sendTo","type":"address"}],"name":"EtherWithdraw","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"pendingAdmin","type":"address"}],"name":"TransferAdminPending","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"newAdmin","type":"address"},{"indexed":false,"name":"previousAdmin","type":"address"}],"name":"AdminClaimed","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"newAlerter","type":"address"},{"indexed":false,"name":"isAdd","type":"bool"}],"name":"AlerterAdded","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"newOperator","type":"address"},{"indexed":false,"name":"isAdd","type":"bool"}],"name":"OperatorAdded","type":"event"}];
const kyberNetProxyContract = new web3.eth.Contract(kyberNetProxyABI, kyberNetProxyAddress);

// Generic ERC20 ABI
const ERC20_ABI = [{"constant":true,"inputs":[],"name":"mintingFinished","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_value","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_token","type":"address"}],"name":"reclaimToken","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_from","type":"address"},{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[],"name":"unpause","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_amount","type":"uint256"}],"name":"mint","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"value","type":"uint256"}],"name":"burn","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"claimOwnership","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"paused","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_subtractedValue","type":"uint256"}],"name":"decreaseApproval","outputs":[{"name":"success","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"}],"name":"balanceOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[],"name":"renounceOwnership","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"finishMinting","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"pause","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"owner","outputs":[{"name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_addedValue","type":"uint256"}],"name":"increaseApproval","outputs":[{"name":"success","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"},{"name":"_spender","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"pendingOwner","outputs":[{"name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"newOwner","type":"address"}],"name":"transferOwnership","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"anonymous":false,"inputs":[],"name":"Pause","type":"event"},{"anonymous":false,"inputs":[],"name":"Unpause","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"burner","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Burn","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"to","type":"address"},{"indexed":false,"name":"amount","type":"uint256"}],"name":"Mint","type":"event"},{"anonymous":false,"inputs":[],"name":"MintFinished","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"previousOwner","type":"address"}],"name":"OwnershipRenounced","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"previousOwner","type":"address"},{"indexed":true,"name":"newOwner","type":"address"}],"name":"OwnershipTransferred","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"owner","type":"address"},{"indexed":true,"name":"spender","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"from","type":"address"},{"indexed":true,"name":"to","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Transfer","type":"event"}]

// this checks and prints the exchange rates between 2 DEXES for any 2 tokens
async function checkPair(args) {
  const { inputTokenSymbol, inputTokenAddress, outputTokenSymbol, outputTokenAddress, inputAmount } = args

  // fetch decimal of token to get precise outputs
  let outputTokenContract = new web3.eth.Contract(ERC20_ABI, outputTokenAddress);
  let outputTokenDecimal = await outputTokenContract.methods.decimals.call().call();

  let uniswapResult = await uniswapRouter.methods.quoteExactInputSingle(inputTokenAddress, outputTokenAddress, 3000, inputAmount, 0).call();
  let kyberResult = await kyberNetProxyContract.methods.getExpectedRate(inputTokenAddress, outputTokenAddress, inputAmount).call();  

  // print in form of table
  console.table([{
    'Input Token': inputTokenSymbol,
    'Output Token': outputTokenSymbol,
    'Input Amount': web3.utils.fromWei(inputAmount, 'Ether'),
    'Uniswap Return': uniswapResult/(10**outputTokenDecimal),
    'Kyber Expected Rate': web3.utils.fromWei(kyberResult.expectedRate, 'Ether'),
    'Kyber Min Return': web3.utils.fromWei(kyberResult.slippageRate, 'Ether'),
    'Timestamp': moment().tz('America/Chicago').format(),
  }])
}

let priceMonitor
let monitoringPrice = false

async function monitorPrice() {
  if(monitoringPrice) {
    return
  }

  console.log("Checking prices...")
  monitoringPrice = true

  try {
    // ADD YOUR CUSTOM TOKEN PAIRS HERE!!!
    await checkPair({
      inputTokenSymbol: 'WETH',
      inputTokenAddress: '0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2',
      outputTokenSymbol: 'MKR',
      outputTokenAddress: '0x9f8f72aa9304c8b593d555f12ef6589cc3a579a2',
      inputAmount: web3.utils.toWei('1', 'ETHER'),
    })

    await checkPair({
      inputTokenSymbol: 'WETH',
      inputTokenAddress: '0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2',
      outputTokenSymbol: 'WBTC',
      outputTokenAddress: '0x2260fac5e5542a773aa44fbcfedf7c193bc2c599',
      inputAmount: web3.utils.toWei('1', 'ETHER'),
    })

    await checkPair({
      inputTokenSymbol: 'WETH',
      inputTokenAddress: '0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2',
      outputTokenSymbol: 'COMP',
      outputTokenAddress: '0xc00e94cb662c3520282e6f5717214004a7f26888',
      inputAmount: web3.utils.toWei('1', 'ETHER'),
    })
  } catch (error) {
    console.error(error)
    monitoringPrice = false
    clearInterval(priceMonitor)
    return
  }

  monitoringPrice = false
}

// Check markets every n seconds
const POLLING_INTERVAL = process.env.POLLING_INTERVAL || 1000 // 1 Second
priceMonitor = setInterval(async () => { await monitorPrice() }, POLLING_INTERVAL)