curl https://api.46elks.com/a1/calls \
  -u <Username>:<API Password> \
  -d from=+46766861020 \
  -d to=+46766861004 \
  -d voice_start='{"play":"https://yourserver.com/files/hello.mp3"}'

import HTTPotion.base
authdata = [basic_auth: {'',

request = %{
            "from"    => "+46766861020",
            "to"      => "+46766861004",
            "voice_start" => "{"play":"https://yourserver.com/files/hello.mp3"}"
           }

request_data = URI.encode_query(request)

HTTPotion.start
HTTPotion.post("https://api.46elks.com/a1/calls",
  [body: request_data , ibrowse: authdata]
)

import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

public class UnirestSendcalls {
  public static void main(String[] args) {
    try {
      System.out.println("Sending calls");

      HttpResponse response = Unirest.post("https://api.46elks.com/a1/calls")
        .basicAuth("","")
        .field("to", "+46766861004")
        .field("from", "+46766861020")
        .field("voice_start", "{"play":"https://yourserver.com/files/hello.mp3"}")
        .asString();

      System.out.println(response.getBody());
      }

    catch (Exception e){
        System.out.println(e);
    }
  }
}

function sendcalls ($calls) {
  $username = "USERNAME";
  $password = "PASSWORD";
  $context = stream_context_create(array(
    'http' => array(
      'method' => 'POST',
      'header'  => 'Authorization: Basic '.
                   base64_encode($username.':'.$password). "\r\n".
                   "Content-type: application/x-www-form-urlencoded\r\n",
      'content' => http_build_query($calls),
      'timeout' => 10
  )));
  $response = file_get_contents("https://api.46elks.com/a1/calls",
    false, $context);

  if (!strstr($http_response_header[0],"200 OK"))
    return $http_response_header[0];
  return $response;
}
$calls = array(
  "from" => "+46766861020",   /* Can be up to 11 alphanumeric characters */
  "to" => "+46766861004",  /* The mobile number you want to send to */
  "voice_start" => '{"play":"https://yourserver.com/files/hello.mp3"}',
);
echo sendcalls($calls);

import requests

auth = (
    '',
    ''
    )

fields = {
    'from': '+46766861020',
    'to': '+46766861004',
    'voice_start': '{"play":"https://yourserver.com/files/hello.mp3"}'
    }

response = requests.post(
    "https://api.46elks.com/a1/calls",
    data=fields,
    auth=auth
    )

print(response.text)

require 'net/http'

uri = URI('https://api.46elks.com/a1/calls')
req = Net::HTTP::Post.new(uri)
req.basic_auth '', ''
req.set_form_data(
  :from => '+46766861020',
  :to => '+46704508449',
  :voice_start => '{"play":"https://yourserver.com/files/hello.mp3"}'
)

res = Net::HTTP.start(
    uri.host,
    uri.port,
    :use_ssl => uri.scheme == 'https') do |http|
  http.request req
end

puts res.body