GoogleSheet App Script Import GDax and Poloniex and email if difference is greater than a threshold percentage.

gistfile1.txt

// Gets GDAX and Poloniex prices for BTC/ETH and BTC/LTC
// Requies arbitrageSheetID set to the id of a google sheet with an APIPull tab.
function checkArbitrageOpportunities() {
  
  var poloniexUrl = 'https://poloniex.com/public?command=returnTicker';
  var poloniexResponse = UrlFetchApp.fetch(poloniexUrl);
  var poloniexApiData = JSON.parse(poloniexResponse.getContentText());
  
  var rates = ['ETH', 'LTC'];
  
  var arbitrageSheetID = '1f4C5X_93OVyxVi1z4VsjPpfyfPBK3-wqjW1Wo79d4MQ';

  var sheet = SpreadsheetApp.openById(arbitrageSheetID);
  var apiTab = sheet.getSheetByName('APIPull');  
  // Clear existing data
  apiTab.getRange('A2:B15').clearContent();
  
  var rowNum = 2;
  
  for(var rate in rates)
  {
    var rateCode = rates[rate];
    var poloniexRate = poloniexApiData['BTC_' + rateCode].last;
    var rateCodeCell = apiTab.getRange('A' + rowNum);
    rateCodeCell.setValue('PLX/BTC-' + rateCode);
    
    var rateCell = apiTab.getRange('B' + rowNum);
    rateCell.setValue(poloniexRate);
    
    rowNum++;
    
    // GDAX
    var gdaxResponse = UrlFetchApp.fetch('https://api.gdax.com/products/' + rateCode + '-BTC/ticker');
    var gdaxData = JSON.parse(gdaxResponse.getContentText());
    
    rateCodeCell = apiTab.getRange('A' + rowNum);
    rateCodeCell.setValue('GDAX/BTC-' + rateCode);
    rateCell = apiTab.getRange('B' + rowNum);
    rateCell.setValue(gdaxData.price);
    
    var percentageDiffCell = apiTab.getRange('C' + rowNum);
    var percentageDiff = percentageDiffCell.getValue();
    var alertThreshold = 0.02;
    
    if (percentageDiff > alertThreshold)
    {
      GmailApp.sendEmail('youremail@somewhere.com', 'Arbitrage Alert for BTC/' + rateCode + ' @ ' + percentageDiff, 
                         'https://www.coinigy.com/main/markets/PLNX/BTC/' + rateCode + '   https://www.coinigy.com/main/markets/GDAX/BTC/' + rateCode);
    }
    
    rowNum++;
    
  }
}