In this tutorial, we will learn how to implement Warm Transfers using ASP.NET MVC and Twilio. The example application simulates a support center, using Twilio to transfer calls from one agent to another.

Read the full tutorial here!

1. First clone this repository and cd into it.

   git clone git@github.com:TwilioDevEd/warm-transfer-csharp.git
   cd warm-transfer-csharp
   

2. Create the sample configuration file and edit it to match your configuration.

rename WarmTransfer.Web\Local.config.example WarmTransfer.Web\Local.config

You can find your TwilioAccountSid and TwilioAuthToken in your Twilio Console. You will also need a TwilioPhoneNumber, you may find it here.

1. Create database and run migrations.

   In Visual Studio, open the following command in the Package Manager Console.

   Update-Database
   

   Make sure Sql Server is up and running.

2. Expose your application to the wider internet using ngrok. This step is important because the application won't work as expected if you run it through localhost.

To start using ngrok in our project you'll have execute to the following line in the command prompt.

ngrok http 55585 -host-header="localhost:55585"

Keep in mind that our endpoint is:

http://<your-ngrok-subdomain>.ngrok.io/Conference/ConnectClient

Remember to update the Local.config file with the generated .

1. Configure Twilio to call your webhooks

You will also need to configure Twilio to call your application when calls are received on your TWILIO_NUMBER. The voice url should look something like this:

http://<your-ngrok-subdomain>.ngrok.io/Conference/ConnectClient

That's it!

1. Navigate to https://<ngrok_subdomain>.ngrok.io in two different browser tabs or windows.

   Notes:

   • Remember to use your SSL enabled ngrok url https. Failing to do this won't allow you to receive incoming calls.

   • The application has been tested with Chrome and Firefox. Safari is not supported at the moment.

2. In one window/tab click Connect as Agent 1 and in the other one click Connect as Agent 2. Now both agents are waiting for an incoming call.

3. Dial your Twilio Number to start a call with Agent 1. Your TWILIO_NUMBER environment variable was set when configuring the application to run.

4. When Agent 1 answers the call from the client, he/she can dial Agent 2 in by clicking on the Dial agent 2 in button.

5. Once Agent 2 answers the call all three participants will have joined the same call. After that Agent 1 can drop the call and leave both the client and Agent 2 having a pleasant talk.

• No warranty expressed or implied. Software is as is. Diggity.
• MIT License
• Lovingly crafted by Twilio Developer Education.