protected void Button1_Click(object sender, EventArgs e) { //Demo Url Process=https://demo.myvirtualmerchant.com/VirtualMerchantDemo/process.do? //Live Url Process= https://www.myvirtualmerchant.com/VirtualMerchant/process.do? //One transaction will done at a time Test Card Number:4111111111111111 StringBuilder ob = new StringBuilder(); ob.Append("https://demo.myvirtualmerchant.com/VirtualMerchantDemo/process.do?"); ob.Append("ssl_merchant_id= Merchant Id"); ob.Append("&ssl_amount= Amount"); ob.Append("&ssl_user_id=User Id");