In today's fast-paced world, where everyone uses hundreds of websites and applications every day, there are numerous in-app notifications, and all communication is critical. However, these in-app notifications will only appear when we start the app. As a result, introducing SMS capabilities into projects can greatly boost user engagement and participation. Twilio, a well-known cloud communications company, has a robust API that enables developers to easily send and receive SMS texts, among other communication functions.

This post will show you how to integrate Twilio to send SMS in a C# MVC project from scratch. So, before we get started with the project, let's register a Twilio account.

Setting up a Twilio account
To create a Twilio account, we first need to sign up, which is simple. If you already have a Twilio account, you can skip step 1 and proceed to step 2.

Step 1: Sign up for Twilio
Sign up by entering your basic information on the following link: www.twilio.com. By clicking "Continue," you will be taken to another page to validate your email address. Once the email address has been verified, you must also verify your phone number. Following that, you will be taken to another page containing a recovery code. Please copy the code and store it somewhere safe for future use.

Step 2: Login to Twilio
If you are checking in for the first time, Twilio will prompt you with a few questions. Simply answer them, and it will lead you to the dashboard/

Step 3. Get the Phone Number
Click on the "Get Phone Number" button, and you will receive the number. Before purchasing their plan, your account will be a trial account, and the number given to you will be a trial number.

Step 4. Get SID and Auth Token
In the same screen, you will have a section named "Account Info", where you will following information -Account SID, Auth Token, and My Twilio phone number, which we will be using during development.

Step 5. Verify Phone Numbers
This step is only for trial account users. Since it is a trial account, you will need to verify the numbers, on which you want to send the SMS using your project. You can skip this step if you have purchased a Twilio SMS plan. To verify numbers follow the following steps.

• Click on the verified phone numbers link, you will be redirected to another page.
• Click on the "Add a new caller ID" button in the right corner. A popup will open to add the number.
• Select the country, number, and mode through which you want to verify the number.
• Click verify the number, you will get an OTP on the number you just entered.
• Enter the OTP to verify the number and it will be shown in verified caller IDs.

Now that you have set up the Twilio account. Let's move to the project.

Setting up the project
You can either create a new project or you can integrate Twilio into an existing project. Here, I have created a demo project to integrate Twilio in it and created a Controller named "TwilioIntegrationController". In this controller, I will be writing Twilio-related code. Let's move to the project.

Step 1. Install dependencies
To be able to integrate Twilio in the project, you will need some dependencies, that will help Twilio run.

• Click on Tools.
• Select "Nuget Package Manager".
• Click "Manage Nuget Package for solution".
• In the Browse section, search for Package "Twilio" and install the solution.
• Then, search "Twilio.AspNet.Mvc" and install it too.

Now that you have installed all the necessary dependencies. Let's move to the next step.

Step 2. Code to Send SMS
In the "TwilioIntegrationController", write your code for sending SMS. Here, I am putting all my code in one file. But you should put the necessary code where it should be.
using Microsoft.AspNetCore.Mvc;
using Twilio;
using Twilio.Rest.Api.V2010.Account;

namespace TwilioIntegration.Controllers
{
public class TwilioIntegrationController : Controller
{
    [Route("send-SMS")]
    public IActionResult SendSMS()
    {
        string sId = ""; // add Account from Twilio
        string authToken = ""; //add Auth Token from Twilio
        string fromPhoneNumber = "+120*******"; //add Twilio phone number

        TwilioClient.Init(sId, authToken);
        var message = MessageResource.Create(
            body: "Hi, there!!",
            from: new Twilio.Types.PhoneNumber(fromPhoneNumber),
            to: new Twilio.Types.PhoneNumber("+9175********") //add receiver's phone number
        );
        Console.WriteLine(message.ErrorCode);
        return View(message);
    }
}
}

Code Explanation
In the above code,

• Add 'using Microsoft.AspNetCore.Mvc;', 'using Twilio;', 'using Twilio.Rest.Api.V2010.Account;' to use Twilio API in the code.
• Then, I have created a method named SendSMS().
• In the method, I created three string variables - sId, authToken, and fromPhoneNumber to store Twilio account SId, Auth Token, and Twilio phone number. I have placed all three in this method, but you should store them in an appsettings file and access them from there.
• Then initiate TwilioClient by passing your account SId and Auth Token, using this lineTwilioClient.Init(sId, authToken);.
• In the next line "MessageResource.Create()" is a method call to create a new SMS message using the Twilio API. It indicates that we are creating a new message resource. We are passing the message body, from phone number and to phone number in it. It creates the message and sends it using the Twilio API.
• In the next line, I have consoled the ErrorCode, if any error occurs during the sending of SMS.

The above image shows that the message was successfully sent from the project, and the body is the same as we specified in our code. However, because we are using a trial account, Twilio automatically inserts the prefix "Sent from your Twilio trial account-" to all messages sent from your trial account. As a result, real-world projects benefit from purchasing a plan.

Conclusion
In this article, we learned how to create a Twilio account, configure it, and connect Twilio with the code in the C# MVC project. By setting up a Twilio account and using Twilio's API, developers may simply send and receive SMS messages, providing a valuable tool for increasing project functionality and user experience.

In the same way, Twilio can be integrated into other languages. The method is virtually identical. You may also use Twilio to deliver WhatsApp messages, audio messages, and other types of messaging by integrating it into your project. This connection enables developers to use Twilio's strong cloud communication infrastructure to improve their projects across many programming languages, resulting in more effective communication and user engagement.