C# Voice Quickstart

Build a simple C# application that answers a call and plays a message to the caller.


You're ready for this quickstart if you've got the following:

A free trial account
A registered application
A configured FreeClimb Number
Your tools and language installed:

Clone your quickstart

For this quickstart, clone the repository for C# Getting Started Tutorial using GitHub's interface or git in the command line.

git clone https://github.com/FreeClimbAPI/CSharp-Getting-Started-Tutorial.git

Make your local server publicly accessible

The fastest way to start testing your FreeClimb application is to temporarily make your local server publicly accessible through a tunneling service. We'll use ngrok to do this. Start by downloading ngrok. Unzip the file to install, then open your terminal and navigate to the directory where you've unzipped ngrok. Use the following command to start a HTTP tunnel on port 3000.

./ngrok http 3000

Once you run ngrok you should receive a response with a public URL, that looks something like this:

ngrok by @inconshreveable

Tunnel Status                 online
Version                       2.0/2.0
Web Interface       
Forwarding                    http://92832de0.ngrok.io -> localhost:3000
Forwarding                    https://92832de0.ngrok.io -> localhost:3000

Connnections                  ttl     opn     rt1     rt5     p50     p90
                              0       0       0.00    0.00    0.00    0.00

The Forwarding URLs point to your local server. Save the URLs and go on to the next step.

Configure your application's endpoints

Now that you've got a public URL you're ready to configure your application's endpoints. We'll be configuring the voiceUrl using your ngrok URL and the route reference /voice/.

Go to the Apps page in your dashboard. You should see your registered FreeClimb app.


Your Apps page with your registered app

Open its App Config, and you'll see its application ID, alias, and some options for URL configuration. Enter your ngrok URL into the voiceUrl field, and add the route /voice/ at the end of the URL.


When you're done the App Config should look something like this:


Example of a completed app config

Save your updated App Config.

Run your app

Once you've updated your App Config you're all ready to run your app! Run the quickstart application with the command:

dotnet run

Once the quickstart app is running, dial your configured FreeClimb number. If everything is set up right, you should hear the message "Hello, FreeClimb!" and then the call will end.

Congratulations! You've just made your first voice calling application!

Next steps

For a more detailed explanation of the code used, see our Accept an Incoming Call tutorial.