IVR: Phone Tree with C# and ASP.NET MVC
This ASP.NET MVC sample application is modeled after a typical call center experience with an IVR, but with more Reese's Pieces.
Stranded aliens can call a phone number and receive instructions on how to get out of earth safely, or call their home planet directly. In this tutorial, we'll show you the key bits of code to make this work.
To run this sample app yourself, download the code and follow the instructions on GitHub.
Read how Livestream and others built IVR with Twilio. Also, find sample code for many web languages and frameworks on our IVR application page.
Respond to the Phone Call
To initiate the phone tree, we need to configure one of our Twilio numbers to send our web application an HTTP request when we get an incoming call.
Click on one of your numbers and configure the Voice URL to point to our app. In our code the route will be
If you don't already have a server configured to use as your webhook, ngrok is a great tool for testing webhooks locally.
With our Twilio number configured, we are prepared to respond to the Twilio request.
Respond to the Twilio request with TwiML
Our Twilio number is now configured to send HTTP requests to this controller on any incoming voice calls. Our app responds with TwiML to tell Twilio what to do in response to the message.
In this case we tell Twilio to
Gather the input from the caller and we
Say a welcome message.
After reading the text to the caller and retrieving their input, Twilio will send this input to our application.
Where to send the caller's input
action parameter takes an absolute or relative URL as a value - in our case, the
When the caller has finished entering digits, Twilio will make a GET or POST request to this URL including a
Digits parameter with the number our caller chose.
After making this request, Twilio will continue the current call using the TwiML received in your response. Any TwiML verbs occuring after a
<Gather> are unreachable, unless the caller enters no digits.
Now that we have told Twilio where to send the caller's input, we can look at how to process that input.
The Main Menu: Process the caller's selection
This route handles processing the caller's input.
If our caller chooses 1 for directions, we use the helper method
ReturnInstructions to respond with TwiML that will
Say directions to our caller's extraction point.
If the caller chooses 2 to call their home planet, we need to gather more input from them. We'll cover this in the next step.
If the caller enters anything else we respond with a TwiML
Redirect to the main menu.
That was only the main menu and the first option. If the caller chooses 2, we will take them to The Planet Directory in order to collect more input.
The Planet Directory: Collect more input from the caller
If our callers choose to call their home planet we will give them the planet directory. This is akin to a typical "company directory" feature of most IVRs.
In our TwiML response we again use a
Gather verb to receive our caller's input. This time, the
action verb points to the
planets route, which will switch our response based on what the caller chooses.
Again we show some options to the caller and instruct Twilio to collect the caller's choice.
The Planet Directory: Connect the caller to another number
In this route, we grab the caller's selection off the request and store it in a variable called
userOption. We then use a
Dial verb with the appropriate phone number to connect our caller to their home planet.
The current numbers are hardcoded, but they could also be read from a database or from a file.
That's it! We've just implemented an IVR phone tree that will delight and serve your customers.
Where to Next?
If you're a C# developer working with Twilio, you might enjoy these other tutorials:
Instantly collect structured data from your users with a survey conducted over a voice call or SMS text messages. Learn how to create your own survey in ASP.NET MVC.
Convert web traffic into phone calls with the click of a button.
Did this help?
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Need some help?
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