mailchimp-api3-batch.php

<?php 
  /* 
   * The following code illustrates how to use batch operations with the 
   * new Mailchimp v3 API. Much of what I found on the net was half baked 
   * and relied on another layer of abstraction.
   *
   */

  $subscribers = [];
  $batch_operations = [];
  $apikey = "xxx-xxx";
  $listkey = "xxx";

  // Single subscriber array 
  // Ideally you would want to iterate over all your subscribers, 
  // and add them to the $subscribers array in the below format
  $subscribers[] = [
    'apikey' => $apikey,
    'email_address' => "joe.soap@exmaple.com",
    'status' => 'subscribed',
    'merge_fields' => [
      'FNAME' => "Joe",
      'LNAME' => "Soap",
    ]
  ];

  // Add an operation to the batch
  // Notice the PUT & the email hash:
  // You don't need the email hash, but you would have to use POST then
  // Use DELETE if you want to delete the subscriber
  // The code below updates/adds the subscriber - POST only adds one
  foreach ($subscribers as $subscriber) {
      array_push($batch_operations, array(
        "method" => "PUT",
        "path" => "/lists/$listkey/members/".md5(strtolower($subscriber['email_address'])),
        "body" => json_encode($subscriber)
      ));
  }

  // Encode the operations request
  $request_encoded = json_encode(array('operations' => $batch_operations));

  // Make the CURL request
  $ch = curl_init();

  // Set up our options for the request
  curl_setopt($ch, CURLOPT_URL, "https://xxxx.api.mailchimp.com/3.0/batches");
  curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json', 'Authorization: Basic '.base64_encode( 'user:'.$apikey )));
  curl_setopt($ch, CURLOPT_USERAGENT, 'PHP-MCAPI/3.0');
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_TIMEOUT, 14000);
  curl_setopt($ch, CURLOPT_POST, true);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $request_encoded);

  // Get the result
  $result = json_decode(curl_exec($ch), 1);

  // Close the CURL connection
  curl_close($ch);

?>