Desde llamadas básicas hasta inteligencia conversacional, todo lo puedes crear con la API de Twilio Voice

# Download the helper library from https://www.twilio.com/docs/python/install
import os
from twilio.rest import Client

# Find your Account SID and Auth Token at twilio.com/console
# and set the environment variables. See http://twil.io/secure
account_sid = os.environ["TWILIO_ACCOUNT_SID"]
auth_token = os.environ["TWILIO_AUTH_TOKEN"]
client = Client(account_sid, auth_token)

call = client.calls.create(
    from_="+15558675310",
    to="+15017122661",
    url="http://demo.twilio.com/docs/voice.xml",
)

print(call.sid)

// Install the C# / .NET helper library from twilio.com/docs/csharp/install

using System;
using Twilio;
using Twilio.Rest.Api.V2010.Account;
using System.Threading.Tasks;

class Program {
    public static async Task Main(string[] args) {
        // Find your Account SID and Auth Token at twilio.com/console
        // and set the environment variables. See http://twil.io/secure
        string accountSid = Environment.GetEnvironmentVariable("TWILIO_ACCOUNT_SID");
        string authToken = Environment.GetEnvironmentVariable("TWILIO_AUTH_TOKEN");

        TwilioClient.Init(accountSid, authToken);

        var call = await CallResource.CreateAsync(
            from: new Twilio.Types.PhoneNumber("+15558675310"),
            to: new Twilio.Types.PhoneNumber("+15017122661"),
            url: new Uri("http://demo.twilio.com/docs/voice.xml"));

        Console.WriteLine(call.Sid);
    }
}

// Install the Java helper library from twilio.com/docs/java/install

import java.net.URI;
import com.twilio.Twilio;
import com.twilio.rest.api.v2010.account.Call;

public class Example {
    // Find your Account SID and Auth Token at twilio.com/console
    // and set the environment variables. See http://twil.io/secure
    public static final String ACCOUNT_SID = System.getenv("TWILIO_ACCOUNT_SID");
    public static final String AUTH_TOKEN = System.getenv("TWILIO_AUTH_TOKEN");

    public static void main(String[] args) {
        Twilio.init(ACCOUNT_SID, AUTH_TOKEN);
        Call call = Call.creator(new com.twilio.type.PhoneNumber("+15017122661"),
                            new com.twilio.type.PhoneNumber("+15558675310"),
                            URI.create("http://demo.twilio.com/docs/voice.xml"))
                        .create();

        System.out.println(call.getSid());
    }
}

<?php

// Update the path below to your autoload.php,
// see https://getcomposer.org/doc/01-basic-usage.md
require_once "/path/to/vendor/autoload.php";

use Twilio\Rest\Client;

// Find your Account SID and Auth Token at twilio.com/console
// and set the environment variables. See http://twil.io/secure
$sid = getenv("TWILIO_ACCOUNT_SID");
$token = getenv("TWILIO_AUTH_TOKEN");
$twilio = new Client($sid, $token);

$call = $twilio->calls->create(
    "+15017122661", // To
    "+15558675310", // From
    ["url" => "http://demo.twilio.com/docs/voice.xml"]
);

print $call->sid;

# Download the helper library from https://www.twilio.com/docs/ruby/install
require 'rubygems'
require 'twilio-ruby'

# Find your Account SID and Auth Token at twilio.com/console
# and set the environment variables. See http://twil.io/secure
account_sid = ENV['TWILIO_ACCOUNT_SID']
auth_token = ENV['TWILIO_AUTH_TOKEN']
@client = Twilio::REST::Client.new(account_sid, auth_token)

call = @client
       .api
       .v2010
       .calls
       .create(
         from: '+15558675310',
         to: '+15017122661',
         url: 'http://demo.twilio.com/docs/voice.xml'
       )

puts call.sid

# Install the twilio-cli from https://twil.io/cli

twilio api:core:calls:create \
   --from +15558675310 \
   --to +15017122661 \
   --url http://demo.twilio.com/docs/voice.xml

curl -X POST "https://api.twilio.com/2010-04-01/Accounts/$TWILIO_ACCOUNT_SID/Calls.json" \
--data-urlencode "From=+15558675310" \
--data-urlencode "To=+15017122661" \
--data-urlencode "Url=http://demo.twilio.com/docs/voice.xml" \
-u $TWILIO_ACCOUNT_SID:$TWILIO_AUTH_TOKEN