Voice API Overview

The Vonage Voice API is the easiest way to build high-quality voice applications in the Cloud. With the Voice API you can:

Contents

In this document you can learn about:

Concepts

Getting Started

Voice Playground

In the Developer Dashboard, you can try out the Voice API interactively in the Voice Playground. Once you are signed up for a Vonage API account, you can go to Voice Playground in the Dashboard (Voice ‣ Voice Playground).

More details are available in this blog post: Meet Voice Playground, Your Testing Sandbox for Vonage Voice Apps

Using the API

The primary way that you'll interact with the Vonage API voice platform is via the public API. To place an outbound call, you make a POST request to https://api.nexmo.com/v1/calls.

To make this easier, Vonage provides Server SDKs in various languages that take care of authentication and creating the correct request body for you.

To get started, choose your language below and replace the following variables in the example code:

Key Description
VONAGE_NUMBER Your Vonage number that the call will be made from. For example 447700900000.
TO_NUMBER The number you would like to call to in E.164 format. For example 447700900001.

Prerequisites

A Vonage application contains the required configuration for your project. You can create an application using the Vonage CLI (see below) or via the dashboard. To learn more about applications see our Vonage concepts guide.

Install the CLI

npm install -g nexmo-cli

Create an application

Once you have the CLI installed you can use it to create a Vonage application. Run the following command and make a note of the application ID that it returns. This is the value to use in NEXMO_APPLICATION_ID in the example below. It will also create private.key in the current directory which you will need in the Initialize your dependencies step

Vonage needs to connect to your local machine to access your answer_url. We recommend using ngrok to do this. Make sure to change demo.ngrok.io in the examples below to your own ngrok URL.

nexmo app:create "Outbound Call code snippet" https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json http://demo.ngrok.io/webhooks/events --keyfile private.key

Execute the following command at your terminal prompt to create the JWT for authentication:

export JWT=$(nexmo jwt:generate $PATH_TO_PRIVATE_KEY application_id=$NEXMO_APPLICATION_ID)

Write the code

Add the following to make-an-outbound-call.sh:

curl -X POST https://api.nexmo.com/v1/calls\
  -H "Authorization: Bearer "$JWT\
  -H "Content-Type: application/json"\
  -d '{"to":[{"type": "phone","number": "$TO_NUMBER"}],
      "from": {"type": "phone","number": "$VONAGE_NUMBER"},
      "answer_url":["https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json"]}'

View full source

Run your code

Save this file to your machine and run it:

bash make-an-outbound-call.sh

Prerequisites

A Vonage application contains the required configuration for your project. You can create an application using the Vonage CLI (see below) or via the dashboard. To learn more about applications see our Vonage concepts guide.

Install the CLI

npm install -g nexmo-cli

Create an application

Once you have the CLI installed you can use it to create a Vonage application. Run the following command and make a note of the application ID that it returns. This is the value to use in NEXMO_APPLICATION_ID in the example below. It will also create private.key in the current directory which you will need in the Initialize your dependencies step

Vonage needs to connect to your local machine to access your answer_url. We recommend using ngrok to do this. Make sure to change demo.ngrok.io in the examples below to your own ngrok URL.

nexmo app:create "Outbound Call code snippet" https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json http://demo.ngrok.io/webhooks/events --keyfile private.key

npm install @vonage/server-sdk

Create a file named make-call.js and add the following code:

const Vonage = require('@vonage/server-sdk')

const vonage = new Vonage({
  apiKey: VONAGE_API_KEY,
  apiSecret: VONAGE_API_SECRET,
  applicationId: VONAGE_APPLICATION_ID,
  privateKey: VONAGE_APPLICATION_PRIVATE_KEY_PATH
})

View full source

Write the code

Add the following to make-call.js:

const ANSWER_URL = 'https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json'

vonage.calls.create({
  to: [{
    type: 'phone',
    number: TO_NUMBER
  }],
  from: {
    type: 'phone',
    number: VONAGE_NUMBER
  },
  answer_url: [ANSWER_URL]
}, (error, response) => {
  if (error) console.error(error)
  if (response) console.log(response)
})

View full source

Run your code

Save this file to your machine and run it:

node make-call.js

Prerequisites

A Vonage application contains the required configuration for your project. You can create an application using the Vonage CLI (see below) or via the dashboard. To learn more about applications see our Vonage concepts guide.

Install the CLI

npm install -g nexmo-cli

Create an application

Once you have the CLI installed you can use it to create a Vonage application. Run the following command and make a note of the application ID that it returns. This is the value to use in NEXMO_APPLICATION_ID in the example below. It will also create private.key in the current directory which you will need in the Initialize your dependencies step

Vonage needs to connect to your local machine to access your answer_url. We recommend using ngrok to do this. Make sure to change demo.ngrok.io in the examples below to your own ngrok URL.

nexmo app:create "Outbound Call code snippet" https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json http://demo.ngrok.io/webhooks/events --keyfile private.key

Add the following to `build.gradle`:

compile 'com.vonage:client:6.2.0'

Create a class named OutboundTextToSpeech and add the following code to the main method:

VonageClient client = VonageClient.builder()
        .applicationId(VONAGE_APPLICATION_ID)
        .privateKeyPath(VONAGE_PRIVATE_KEY_PATH)
        .build();

View full source

Write the code

Add the following to the main method of the OutboundTextToSpeech class:

final String ANSWER_URL = "https://nexmo-community.github.io/ncco-examples/talk.json";

client.getVoiceClient().createCall(new Call(TO_NUMBER, VONAGE_NUMBER, ANSWER_URL));

View full source

Run your code

We can use the application plugin for Gradle to simplify the running of our application. Update your build.gradle with the following:

  apply plugin: 'application'
  mainClassName = project.hasProperty('main') ? project.getProperty('main') : ''

Run the following gradle command to execute your application, replacing com.vonage.quickstart.voice with the package containing OutboundTextToSpeech:

gradle run -Pmain=com.vonage.quickstart.voice.OutboundTextToSpeech

Prerequisites

A Vonage application contains the required configuration for your project. You can create an application using the Vonage CLI (see below) or via the dashboard. To learn more about applications see our Vonage concepts guide.

Install the CLI

npm install -g nexmo-cli

Create an application

Once you have the CLI installed you can use it to create a Vonage application. Run the following command and make a note of the application ID that it returns. This is the value to use in NEXMO_APPLICATION_ID in the example below. It will also create private.key in the current directory which you will need in the Initialize your dependencies step

Vonage needs to connect to your local machine to access your answer_url. We recommend using ngrok to do this. Make sure to change demo.ngrok.io in the examples below to your own ngrok URL.

nexmo app:create "Outbound Call code snippet" https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json http://demo.ngrok.io/webhooks/events --keyfile private.key

Install-Package Vonage

Create a file named MakeOutboundCall.cs and add the following code:

using Vonage;
using Vonage.Request;
using Vonage.Voice;
using Vonage.Voice.Nccos.Endpoints;

View full source

Add the following to MakeOutboundCall.cs:

var creds = Credentials.FromAppIdAndPrivateKeyPath(VONAGE_APPLICATION_ID, VONAGE_PRIVATE_KEY_PATH);
var client = new VonageClient(creds);

View full source

Write the code

Add the following to MakeOutboundCall.cs:

var ANSWER_URL = "https://nexmo-community.github.io/ncco-examples/text-to-speech.json";
var toEndpoint = new PhoneEndpoint() { Number = TO_NUMBER };
var fromEndpoint = new PhoneEndpoint() { Number = VONAGE_NUMBER };

var command = new CallCommand() { To = new Endpoint[] { toEndpoint }, From = fromEndpoint, AnswerUrl = new[] { ANSWER_URL } };
var response = client.VoiceClient.CreateCall(command);

View full source

Prerequisites

A Vonage application contains the required configuration for your project. You can create an application using the Vonage CLI (see below) or via the dashboard. To learn more about applications see our Vonage concepts guide.

Install the CLI

npm install -g nexmo-cli

Create an application

Once you have the CLI installed you can use it to create a Vonage application. Run the following command and make a note of the application ID that it returns. This is the value to use in NEXMO_APPLICATION_ID in the example below. It will also create private.key in the current directory which you will need in the Initialize your dependencies step

Vonage needs to connect to your local machine to access your answer_url. We recommend using ngrok to do this. Make sure to change demo.ngrok.io in the examples below to your own ngrok URL.

nexmo app:create "Outbound Call code snippet" https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json http://demo.ngrok.io/webhooks/events --keyfile private.key

composer require vonage/client

Create a file named text-to-speech-outbound.php and add the following code:

$keypair = new \Vonage\Client\Credentials\Keypair(
    file_get_contents(VONAGE_APPLICATION_PRIVATE_KEY_PATH),
    VONAGE_APPLICATION_ID
);

$client = new \Vonage\Client($keypair);

View full source

Write the code

Add the following to text-to-speech-outbound.php:

$outboundCall = new \Vonage\Voice\OutboundCall(
    new \Vonage\Voice\Endpoint\Phone(TO_NUMBER),
    new \Vonage\Voice\Endpoint\Phone(VONAGE_NUMBER)
);
$outboundCall->setAnswerWebhook(
    new \Vonage\Voice\Webhook(
        'https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json',
        \Vonage\Voice\Webhook::METHOD_GET
    )
);
$response = $client->voice()->createOutboundCall($outboundCall);

var_dump($response);

View full source

Run your code

Save this file to your machine and run it:

php text-to-speech-outbound.php

Prerequisites

A Vonage application contains the required configuration for your project. You can create an application using the Vonage CLI (see below) or via the dashboard. To learn more about applications see our Vonage concepts guide.

Install the CLI

npm install -g nexmo-cli

Create an application

Once you have the CLI installed you can use it to create a Vonage application. Run the following command and make a note of the application ID that it returns. This is the value to use in NEXMO_APPLICATION_ID in the example below. It will also create private.key in the current directory which you will need in the Initialize your dependencies step

Vonage needs to connect to your local machine to access your answer_url. We recommend using ngrok to do this. Make sure to change demo.ngrok.io in the examples below to your own ngrok URL.

nexmo app:create "Outbound Call code snippet" https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json http://demo.ngrok.io/webhooks/events --keyfile private.key

pip install vonage

Create a file named make-an-outbound-call.py and add the following code:

client = vonage.Client(
    application_id=VONAGE_APPLICATION_ID,
    private_key=VONAGE_APPLICATION_PRIVATE_KEY_PATH,
)

View full source

Write the code

Add the following to make-an-outbound-call.py:

voice = vonage.Voice(client)

response = voice.create_call({
  'to': [{'type': 'phone', 'number': TO_NUMBER}],
  'from': {'type': 'phone', 'number': VONAGE_NUMBER},
  'answer_url': ['https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json']
})

pprint(response)

View full source

Run your code

Save this file to your machine and run it:

python3 make-an-outbound-call.py

Prerequisites

A Vonage application contains the required configuration for your project. You can create an application using the Vonage CLI (see below) or via the dashboard. To learn more about applications see our Vonage concepts guide.

Install the CLI

npm install -g nexmo-cli

Create an application

Once you have the CLI installed you can use it to create a Vonage application. Run the following command and make a note of the application ID that it returns. This is the value to use in NEXMO_APPLICATION_ID in the example below. It will also create private.key in the current directory which you will need in the Initialize your dependencies step

Vonage needs to connect to your local machine to access your answer_url. We recommend using ngrok to do this. Make sure to change demo.ngrok.io in the examples below to your own ngrok URL.

nexmo app:create "Outbound Call code snippet" https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json http://demo.ngrok.io/webhooks/events --keyfile private.key

gem install vonage

Create a file named outbound_tts_call.rb and add the following code:

client = Vonage::Client.new(
  api_key: VONAGE_API_KEY,
  api_secret: VONAGE_API_SECRET,
  application_id: VONAGE_APPLICATION_ID,
  private_key: File.read(VONAGE_APPLICATION_PRIVATE_KEY_PATH)
)

View full source

Write the code

Add the following to outbound_tts_call.rb:

response = client.voice.create(
  to: [{
    type: 'phone',
    number: TO_NUMBER
  }],
  from: {
    type: 'phone',
    number: VONAGE_NUMBER
  },
  answer_url: [
    'https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json'
  ]
)

puts response.inspect

View full source

Run your code

Save this file to your machine and run it:

ruby outbound_tts_call.rb

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Reference