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Nexmo Voice API with ASP.NET: Before you start

July 28, 2017 Published by

This is part of a series on using The Nexmo Voice API with ASP.NET projects. It continues the “Getting Started with Nexmo and ASP.NET” series, which follows our Getting Started series on SMS APIs.
In this tutorial, we are going to set up an ASP.NET project in Visual Studio that has all the configuration necessary to connect to The Nexmo Voice API. This makes it possible to add phone call abilities to an ASP.NET application. Future blog posts will show how to integrate the Voice API into your application; this is to show you how to get started.

Configuring a Nexmo application

In order to be able to use The Nexmo Voice API , you’ll have to use a Nexmo Application.
A Nexmo application contains the security and configuration information you need to interact with the Nexmo Voice REST API and easily use the Voice API.

All requests to the Voice API require authentication. You must generate a private key with the Application API, which allows you to create JSON Web Tokens (JWT) to make the requests. An application associated public/private keys can be created in two ways.

The Nexmo application dashboard

If you go to your Nexmo dashboard, under the Voice tab, you can see that you can create an application.

Complete the required fields and then click “Generate public/private key pair” this will prompt you to download your private key (keep this safe!) as well as populating the public key for you.

You can read more about our application dashboard and how it makes Nexmo Voice application management easier to set up in our blog post.

The Nexmo CLI

First, let’s install Nexmo’s CLI from npm

then set it up with your Nexmo API key and secret.

This will save your app credentials to ..\.nexmorc

Now that the configuration is done, the next step is creating the Voice Application using the command app:create.

With both options, you need to register an application name, for example “My first voice app” and two webhook endpoints to specify the answer and event URLs.

When the application is successfully created, the CLI returns the application ID and private key, both are required to interact with the Nexmo’s Voice API.

ASP.NET project setup

Now that we have generated our public/private key pair and our Nexmo application let’s look at how we should configure our ASP.NET project. You may have noticed that there is now more than one ASP.Net platform : The ASP.Net is built specifically for Windows while ASP.Net Core is the new open sourced and cross-platform framework.
We will try to cover both when there is a difference in code otherwise we will use one or the other with a focus on ASP.Net Core as it’s the way forward.

ASP.Net Web project setup

First, open up Visual Studio and create a new ASP.NET Web Application (.NET Framework) project.

Select the MVC Template and ensure the Authentication type is set to No Authentication. Click OK to create the project.

ASP.Net Core project setup

In Visual Studio, create a new project and choose ASP.NET Core Web Application.

Then select the Web Application template.

Installing the Nexmo C# Client Library

Whether you opt for ASP.Net Web or Core project, the following steps are the same.
Install the Nexmo C# Client Library via the NuGet Package Manager Console.

Next, under the Tools dropdown menu, locate NuGet Package Manager and click Manage NuGet Packages for Solution. Under the Updates tab, select the Update All Packages box and click the Update button.

Add a JSON file (appsettings.json) to your project. Inside which you will add your Nexmo credentials.

Now you’re ready to dive into code. Let’s see how you can make a Text-to-Speech phone call in your ASP.NET project with the Voice API.

Learn more about Nexmo’s APIs and ASP.NET

This post was just a quick introduction into setting up your first Nexmo application with ASP.NET.
Now you are ready to dive into code and learn How to make a Text-to-Speech phone call in ASP.NET with The Nexmo Voice API

Also why not try sending an SMS with ASP.NET MVC? Or learn how to receive SMS with ASP.NET MVC? Both posts are on our developer blog. You might also be interested in our open source .NET client which is available on Github.

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