Mailchimp subscribe php api 3

mailchimp-subscribe-api-3.php

<?php 

  $data = [
      'email'     => $_POST['email'],
      'status'    => 'subscribed',
      'firstname' => $_POST['name'],
  ];
  // accesses key and list
  $apiKey = '11111111111111111111111111111111-1234';
  $listId = '1234567890';

  $memberId = md5(strtolower($data['email']));
  $dataCenter = substr($apiKey,strpos($apiKey,'-')+1);
  $url = 'https://' . $dataCenter . '.api.mailchimp.com/3.0/lists/' . $listId . '/members/' . $memberId;

  $json = json_encode([
      'email_address' => $data['email'],
      'status'        => $data['status'], // "subscribed","unsubscribed","cleaned","pending"
      'merge_fields'  => [
          'FNAME'     => $data['firstname']
      ]
  ]);

  $ch = curl_init($url);
  curl_setopt($ch, CURLOPT_USERPWD, 'user:' . $apiKey);
  curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_TIMEOUT, 10);
  curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PUT');
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $json);                                                                                                                 
  $result = curl_exec($ch);
  curl_close($ch);
  // Response.
  print_r($result);