title: How to integrate paytm with mobile app using php
body: <p>I am trying to integrate Paytm with andorid and ios app using php,
  I found code on github and two files "generateChecksum.php" and "verifyChecksum.php" (added my merchant id in "config_paytm" file)
  and i generated checksum id succesfully,now what is the next step ? How can i integrate paytm with app using php ?</p>
  
  <p>here is code for generateChecksum.php</p>
  
  <pre><code>$findme   = 'REFUND';
  $findmepipe = '|';
  
  $paramList = array();
  
  $paramList["MID"] = '1';
  $paramList["ORDER_ID"] = '11';
  $paramList["CUST_ID"] = '1';
  $paramList["INDUSTRY_TYPE_ID"] = '1';
  $paramList["CHANNEL_ID"] = '1';
  $paramList["TXN_AMOUNT"] = '1';
  $paramList["WEBSITE"] = '';
  
  foreach($_POST as $key=&gt;$value)
  {  
    $pos = strpos($value, $findme);
    $pospipe = strpos($value, $findmepipe);
    if ($pos === false || $pospipe === false) 
      {
          $paramList[$key] = $value;
      }
  }
  
  
  
  //Here checksum string will return by getChecksumFromArray() function.
  $checkSum = getChecksumFromArray($paramList,PAYTM_MERCHANT_KEY);
  //print_r($_POST);
   echo json_encode(array("CHECKSUMHASH" =&gt; $checkSum,"ORDER_ID" =&gt; $_POST["ORDER_ID"], "payt_STATUS" =&gt; "1"),JSON_UNESCAPED_SLASHES);
  </code></pre>