Pinless Conference CallsUsing .NET


This guide shows how to create and configure conference calling, which lets you connect multiple people to one call at the same time.

You can implement PINless conference calls either by using our PHLO visual workflow builder or our APIs and XML documents. Follow the instructions in one of the tabs below.

You can create and deploy a workflow to implement conference calling with a few clicks on the PHLO canvas.


To get started, you need a Plivo account — sign up with your work email address if you don’t have one already. To receive incoming calls, you must have a voice-enabled Plivo phone number. You can rent numbers from the Numbers page of the Plivo console, or by using the Numbers API.

Create the PHLO

To create a PHLO, visit the PHLO page of the Plivo console. If this is your first PHLO, the PHLO page will be empty.

  • In the Choose your use case pop-up, click Build my own. The PHLO canvas will appear with the Start node.
    Note: The Start node is the starting point of any PHLO. It lets you trigger a PHLO to start upon one of three actions: incoming SMS message, incoming call, or API request.
  • From the list of components on the left side, drag and drop the Conference Bridge component onto the canvas. When a component is placed on the canvas it becomes a node.

  • Draw a line to connect the Start node‘s Incoming Call trigger state to the Conference Bridge node.

  • In the Configuration tab at the right of the canvas, enter a Conference ID for your conference. You can also add an announcement message to greet callers, and configure the hold music.

  • Once you’ve configured the node, click Validate to save the configuration.
  • Give the PHLO a name by clicking in the upper left, then click Save.

Your complete PHLO should look like this.

Conference without Pin

Assign the PHLO to a Plivo number

Once you’ve created and configured your PHLO, assign it to a Plivo number.

  • On the Numbers page of the console, under Your Numbers, click the phone number you want to use for the PHLO.
  • In the Number Configuration box, select PHLO from the Application Type drop-down.
  • From the PHLO Name drop-down, select the PHLO you want to use with the phone number, then click Update Number.

Assign PHLO to a Plivo Number


You can now call to your Plivo phone number and see how callers are added to a conference call.

For more information about creating a PHLO application, see the PHLO Getting Started guide. For information on components and their variables, see the PHLO Components Library.

Here’s how to receive a call on a Plivo number and add the caller to a conference call named “demo” using the Conference XML element.

How it works

PINless Conference Call Flow


To get started, you need a Plivo account — sign up with your work email address if you don’t have one already. You must have a voice-enabled Plivo phone number to receive incoming calls; you can rent numbers from the Numbers page of the Plivo console, or by using the Numbers API. If this is your first time using Plivo APIs, follow our instructions to set up a .NET development environment and a web server and safely expose that server to the internet.

Create an MVC controller to implement a conference call

In Visual Studio, create a controller called ConferencecallController.cs and paste into it this code.

using System;
using Plivo.XML;
using System.Collections.Generic;
using Microsoft.AspNetCore.Mvc;

namespace Conferencecall
	public class ConferencecallController : Controller
		public IActionResult Index()
			Plivo.XML.Response resp = new Plivo.XML.Response();
			resp.AddSpeak("You will now be placed into the demo conference", 
             new Dictionary<string, string>() { });
               new Dictionary<string, string>()
				{"startConferenceOnEnter", "true"},
				{"endConferenceOnExit", "true"},
				{"waitSound", "https://<yourdomain>.com/waitmusic/"}
			var output = resp.ToString();

			return this.Content(output, "text/xml");

Run the project and you should see your basic server application in action at http://localhost:5000/conferencecall/.

Create a Plivo application for the conference call

Associate the .NET application you created with Plivo by creating a Plivo application. Visit Voice > Applications in the Plivo console and click on Add New Application, or use Plivo’s Application API.

Give your application a name — we called ours Conference Call. Enter the server URL you want to use (for example https://<yourdomain>.com/conference_call/) in the Answer URL field and set the method to POST. Click Create Application to save your application.

Create Conference Application

Assign a Plivo number to your application

Navigate to the Numbers page and select the phone number you want to use for this application.

From the Application Type drop-down, select XML Application.

From the Plivo Application drop-down, select Conference Call (the name we gave the application).

Click Update Number to save.

Assign Conference Application


Make a call to your Plivo number. You should be placed into a conference.