{
  "return_code":0,
  "return_message":"",
  "result":{
    "variants_count":6,
    "variant":[
      {
        "id":"9",
        "name":"product 3 confic-pineApple-brown",
        "description":"Padded adjustable dividers allow you to customize the case to your equipment.Durable shell, rugged water repellent nylon fabric, looks great and protects your valuable equipment.Large front pocket with internal compartments, perfect for notes & papers.Tripod straps on bottom of case to easily carry a tripod or monopod.Padded twin side pockets for extra storage and quick access.Shoulder strap with non slip, adjustable shoulder pad for carrying comfort.\r\n\r\n \r\n\r\nFeatures\r\n\r\nBag dimensions: 11 by 8.7 by 7.9 inches (width x height x depth)\r\nWater-repellant nylon fabric\r\nHolds 1 SLR camera body with 3 to 5 lenses, flash and small accessories\r\nAdjustable interior dividers\r\nStraps for tripod or monopod\r\nFront pocket with internal compartments\r\nMesh film and inner cover battery pocket\r\nTwo side pockets\r\nAdjustable, non-slip shoulder strap\r\n",
        "price":2340
      },
      {
        "id":"10",
        "name":"product 3 confic-nuke-white",
        "description":"Padded adjustable dividers allow you to customize the case to your equipment.Durable shell, rugged water repellent nylon fabric, looks great and protects your valuable equipment.Large front pocket with internal compartments, perfect for notes & papers.Tripod straps on bottom of case to easily carry a tripod or monopod.Padded twin side pockets for extra storage and quick access.Shoulder strap with non slip, adjustable shoulder pad for carrying comfort.\r\n\r\n \r\n\r\nFeatures\r\n\r\nBag dimensions: 11 by 8.7 by 7.9 inches (width x height x depth)\r\nWater-repellant nylon fabric\r\nHolds 1 SLR camera body with 3 to 5 lenses, flash and small accessories\r\nAdjustable interior dividers\r\nStraps for tripod or monopod\r\nFront pocket with internal compartments\r\nMesh film and inner cover battery pocket\r\nTwo side pockets\r\nAdjustable, non-slip shoulder strap\r\n",
        "price":2696
      },
      {
        "id":"11",
        "name":"product 3 confic-abibas-blue",
        "description":"Padded adjustable dividers allow you to customize the case to your equipment.Durable shell, rugged water repellent nylon fabric, looks great and protects your valuable equipment.Large front pocket with internal compartments, perfect for notes & papers.Tripod straps on bottom of case to easily carry a tripod or monopod.Padded twin side pockets for extra storage and quick access.Shoulder strap with non slip, adjustable shoulder pad for carrying comfort.\r\n\r\n \r\n\r\nFeatures\r\n\r\nBag dimensions: 11 by 8.7 by 7.9 inches (width x height x depth)\r\nWater-repellant nylon fabric\r\nHolds 1 SLR camera body with 3 to 5 lenses, flash and small accessories\r\nAdjustable interior dividers\r\nStraps for tripod or monopod\r\nFront pocket with internal compartments\r\nMesh film and inner cover battery pocket\r\nTwo side pockets\r\nAdjustable, non-slip shoulder strap\r\n",
        "price":2372
      },
      {
        "id":"12",
        "name":"product 3 confic-abibas-green",
        "description":"Padded adjustable dividers allow you to customize the case to your equipment.Durable shell, rugged water repellent nylon fabric, looks great and protects your valuable equipment.Large front pocket with internal compartments, perfect for notes & papers.Tripod straps on bottom of case to easily carry a tripod or monopod.Padded twin side pockets for extra storage and quick access.Shoulder strap with non slip, adjustable shoulder pad for carrying comfort.\r\n\r\n \r\n\r\nFeatures\r\n\r\nBag dimensions: 11 by 8.7 by 7.9 inches (width x height x depth)\r\nWater-repellant nylon fabric\r\nHolds 1 SLR camera body with 3 to 5 lenses, flash and small accessories\r\nAdjustable interior dividers\r\nStraps for tripod or monopod\r\nFront pocket with internal compartments\r\nMesh film and inner cover battery pocket\r\nTwo side pockets\r\nAdjustable, non-slip shoulder strap\r\n",
        "price":2465
      },
      {
        "id":"13",
        "name":"product 3 confic-Sonya-white",
        "description":"Padded adjustable dividers allow you to customize the case to your equipment.Durable shell, rugged water repellent nylon fabric, looks great and protects your valuable equipment.Large front pocket with internal compartments, perfect for notes & papers.Tripod straps on bottom of case to easily carry a tripod or monopod.Padded twin side pockets for extra storage and quick access.Shoulder strap with non slip, adjustable shoulder pad for carrying comfort.\r\n\r\n \r\n\r\nFeatures\r\n\r\nBag dimensions: 11 by 8.7 by 7.9 inches (width x height x depth)\r\nWater-repellant nylon fabric\r\nHolds 1 SLR camera body with 3 to 5 lenses, flash and small accessories\r\nAdjustable interior dividers\r\nStraps for tripod or monopod\r\nFront pocket with internal compartments\r\nMesh film and inner cover battery pocket\r\nTwo side pockets\r\nAdjustable, non-slip shoulder strap\r\n",
        "price":2668
      },
      {
        "id":"20",
        "name":"Bag Green XXL",
        "description":"",
        "price":0
      }
    ]
  }
}

index.php

<?php

include_once 'Connector.php';

$api = new Connector('PASTE_YOUR_API_KEY','PASTE_YOUR_STORE_KEY');

$params = array(
  'product_id'  => 8,
);

try {

  /**
   * Return stdClass
   */
  $result = $api->request('product.variant.list', $params);

  echo "Variant list: \n";

  foreach($result->variant[0] as $variant) {

    echo "Variant ID: "  . $variant->id   . "\n" .
         "Name: "        . $variant->name . "\n" .
         "Description: " . $variant->description . "\n" .
         "Price: "       . $variant->price . "\n\n";

  }

} catch (Exception $e) {

  echo '#' . $e->getCode() . ' ' . $e->getMessage();

}

Connector.php

<?php

/**
 * Class Connector
 */
class Connector
{
  /**
   * URL to API API2Cart
   *
   * @var string A2C_URL
   */
  const A2C_URL = 'https://api.api2cart.com/v1.0/';

  /**
   * @var array $_params
   */
  private $_params = array();

  /**
   * @param string $apiKey
   * @param string $storeKey
   */
  public function __construct($apiKey, $storeKey = null)
  {
    $this->_params['api_key']   = $apiKey;

    if($storeKey !== null) {
      $this->_params['store_key'] = $storeKey;
    }
  }


  /**
   * Send request to API2Cart
   *
   * @param string $method Name method
   * @param array  $params List params for method
   *
   * @return stdClass
   *
   * @throws Exception
   */
  public function request($method, $params = array())
  {

    $params = array_merge($this->_params,$params);

    $ch = curl_init();

    $url = self::A2C_URL . $method . '.json?' . http_build_query($params);

    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
    curl_setopt($ch, CURLOPT_HEADER, false);
    curl_setopt($ch, CURLOPT_TIMEOUT, 300);
    curl_setopt($ch, CURLINFO_HEADER_OUT,true);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_USERAGENT, 
      "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; " .
      "rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1");
    curl_setopt($ch, CURLOPT_HTTPHEADER, array (
      "Accept: */*",
    ));

    try {

      $response = trim(curl_exec($ch));

      if(curl_errno($ch) != CURLE_OK) {
        throw new Exception(curl_error($ch));
      }

      curl_close($ch);

      return $this->validate($response);

    } catch (Exception $e) {

      throw $e;

    }
  }

  /**
   * Validate received response
   *
   * @param string $response Response
   *
   * @return stdClass
   *
   * @throws Exception
   */
  private function validate($response)
  {
    $result = json_decode($response);

    if($result === null) {
      throw new Exception('Response NULL');
    }

    if($result->return_code != 0) {
      throw new Exception($result->return_message, $result->return_code);
    }

    return $result->result;
  }
}