Overview

NOTE: This section of the docs describes Applications V2 functionality.

A Nexmo application contains the security and configuration information you need to connect to Nexmo endpoints and use the Nexmo APIs.

Each Nexmo application created can support multiple capabilities - for example you can create an Application that supports using the Voice, Messages and RTC APIs.

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To illustrate the use of Nexmo applications, a brief summary for creating and using a Nexmo voice application is given here:

  1. Create a Nexmo application using the CLI, the Dashboard or the Application API.
  2. Make sure you configure your webhook URLs. Nexmo will call back on these URLs with important information.
  3. Associate a Nexmo number with your Nexmo application.
  4. Write your web application. Implement the webhook endpoints you configured in step 2, using the Nexmo APIs as required.

For instance, if you want to create an application that forwards inbound calls to a destination phone, you would perform the following steps:

  1. You create a Nexmo application that has voice capabilities.
  2. You configure the answer and event webhook URLs.
  3. You associate a Nexmo number with your Nexmo application.
  4. You implement a web application that responds to callbacks on the webhook URLs.
  5. When an inbound call is made to the Nexmo number associated with the Nexmo application, an NCCO is returned on the answer_url.

Other types of application, such as those with Messages and Dispatch capabilities, have a slightly different process which is described in the relevant sections of this documentation.

The following sections explain Nexmo applications in more detail.

Structure

Each application has the following:

Name Description
id Used to identify each application and used in conjunction with private_key to generate JWTs.
name The application name.
capabilities Describes the types of functionality this application will support. The capabilities voice, messages, rtc, vbc. Any number of these capabilities can be supported in one application. You also set webhooks for each capability specified. Nexmo sends and retrieves information via the webhook endpoints.
keys Contains private_key and public_key. You use the private key to generate the JWTs used to authenticate your calls to the Nexmo APIs. The public key is used by Nexmo to authenticate the JWT in your requests to Nexmo API.

Capabilities

A Nexmo application can use various APIs, including Voice, Messages and Dispatch, Conversation, and Client SDK.

When creating an application you can specify the capabilities you want your application to support. For each capability you can set webhooks depending on what capabilities you want, for example for an application with an rtc capability you could specify an event URL to receive RTC events. If your application also needed to use voice capabilities you could also potentially set an Answer URL to receive a call answered webhook, a fallback URL in case your Answer URL fails, and another Event URL to receive voice call related events.

A summary of capabilities is given in the following table:

Capability Description
voice Used to support Voice capabilities.
messages Used to support Messages and Dispatch API capabilities.
rtc Used to support WebRTC capabilities. Typically for use with Client SDK.
vbc Used to determine pricing, but currently has no other capabilities.

Webhooks

The webhook URLs you provide when creating an application depend on the application capabilities required. The following table summarizes the webhooks:

Capability API used Webhooks available
voice Voice answer_url, fallback_answer_url, event_url
messages Messages and Dispatch inbound_url, status_url
rtc Client SDK event_url
vbc VBC None

Webhook types

The following table describes webhooks available per capability:

Capability Webhook API Example Description
voice answer_url Voice https://example.com/webhooks/answer The URL that Nexmo make a request to when a call is placed/received. Must return an NCCO.
voice fallback_answer_url Voice https://example.com/webhooks/fallback If the fallback_answer_url is set, Nexmo makes a request to it if the answer_url is offline or returns an HTTP error code or the event_url is offline or returns an error code and an event is expected to return an NCCO. The fallback_answer_url must return an NCCO. If your fallback_answer_url fails after two attempts for an initial NCCO, the call is ended. If your fallback_answer_url fails after two attempts for a call in progress, the call flow is continued.
voice event_url Voice https://example.com/webhooks/event Nexmo will send call events (e.g. ringing, answered) to this URL.
messages inbound_url Messages, Dispatch https://example.com/webhooks/inbound Nexmo will forward inbound messages to this URL.
messages status_url Messages, Dispatch https://example.com/webhooks/status Nexmo will send message status updates (for example, delivered, seen) to this URL.
rtc event_url Client SDK, Conversation https://example.com/webhooks/rtcevent Nexmo will send RTC events to this URL.
vbc None Voice endpoint None Not used

Creating applications

There are four main ways to create an application:

  1. In the Nexmo Dashboard. Applications are then listed in the your applications section of the Dashboard.
  2. Using the Nexmo CLI.
  3. Using the Application API.
  4. Using one of the Nexmo Server SDKs.

Managing applications using the CLI

Code Snippets

Reference