Send SMS and MMS Messages in C# and .NET

In this tutorial, we’ll show you how to use Twilio’s Programmable Messaging to send SMS and MMS messages from your .NET Framework or .NET Core application.

The code samples in this tutorial use Twilio’s .NET helper library. Let’s get started!

Sign up for (or log in to) your Twilio account

Before you can send messages, you’ll need to sign up for a Twilio account and purchase a Twilio phone number.

If you’re brand new to Twilio, you can sign up for a free trial account to get started. Once you've signed up, head over to your Console and grab your Account SID and your Auth Token. You will need those values for the code samples below.

Get a phone number with SMS (and MMS) capabilities

Sending messages requires a Twilio phone number with SMS capabilities. If you don’t currently own a Twilio phone number with SMS capabilities, you’ll need to buy one. After navigating to the Buy a Number page, check the 'SMS' box and click 'Search':

If you live in the US or Canada and also wish to send MMS messages, you can select the 'MMS' box. When viewing the search results, you can see the capability icons in the list of available numbers:

Find a number you like and click "Buy" to add it to your account.

Now that you have a Twilio phone number you can start sending messages to mobile devices.

Send an SMS message in C# and .NET via the REST API

To send an outgoing SMS message from your Twilio account you’ll need to make an HTTP POST to Twilio's Message resource.

Twilio's NuGet package for .NET helps you to create a new instance of the Message resource, specifying the To, From, and Body parameters of your message. Let's create a new .NET project and add the Twilio NuGet Package.

Jump to the appropriate section below based on whether you are working with Visual Studio or the dotnet command line tool.

Create a new project with Visual Studio

Open Visual Studio and select the "File" menu and choose "New" then "Project..." and select "Console App (.NET Framework)" or "Console App (.NET Core)".

Then, select "Tools," "NuGet Package Manager," and "Package Manager Console" from the main menu in Visual Studio and type this command:

Install-Package Twilio​

You're now ready to skip to writing the code.

Create a new project with the .NET CLI

Run these commands to create a new .NET project and install the Twilio NuGet package:

mkdir TwilioSend
cd TwilioSend
dotnet new console
dotnet add package Twilio

Write C# code to send an SMS

Now, open the Program.cs file and replace it with the following code.

Replace the placeholder values for accountSid and authToken with your unique values. You can find these in your Twilio console.

You’ll tell Twilio which phone number to use to send this message by replacing the From number with the Twilio phone number you purchased earlier.

Next, specify yourself as the message recipient by replacing the To number with your mobile phone number. Both of these parameters must use E.164 formatting ("+" and a country code, e.g., +16175551212)

We also include the Body parameter, which contains the content of the SMS we’re going to send.

Once you’ve updated the code sample, you can test it out by running it from Visual Studio (with the green triangle "play" button) or with the .NET CLI:

dotnet run

In just a few moments you should receive an SMS!

Let’s take a moment to understand what’s going on behind the scenes when you send this request to Twilio.

Twilio's response

When Twilio receives your request to send an SMS via the REST API, it will check that you’ve included a valid Twilio phone number in the From field. Twilio will then either queue the SMS or return this HTTP error in its response to your request.

Assuming your request didn't result in any errors, Twilio's HTTP response will include the SID of the new message. This unique identifier will help us reference this message later: in the code above, we printed that SID to the terminal.

Twilio's JSON response includes a robust amount of data about your message. A sample response might look like this:

{"sid": "SMxxxxxxxxxxxxxxx", 
 "date_created": "Thu, 09 Aug 2018 17:26:08 +0000", 
 "date_updated": "Thu, 09 Aug 2018 17:26:08 +0000", 
 "date_sent": null, 
 "account_sid": "ACxxxxxxxxxxxxxxxx", 
 "to": "+15558675310",
 "from": "+15017122661",
 "messaging_service_sid": null,
 "body": "This is the ship that made the Kessel Run in fourteen parsecs?", 
 "status": "queued", 
 "num_segments": "1", 
 "num_media": "0",
 "direction": "outbound-api",
 "api_version": "2010-04-01",
 "price": null,
 "price_unit": "USD",
 "error_code": null,
 "error_message": null,
 "uri": "/2010-04-01/Accounts/ACxxxxxxxxx/Messages/SMxxxxxxxxxxxx.json",
 "subresource_uris": {
     "media": "/2010-04-01/Accounts/ACxxxxxxxx/Messages/SMxxxxxxxxxxxxx/Media.json"
 }
}

You can access any of these attributes from your .NET code, much like we did when we printed the message.Sid.

Try adding a logging statement like Console.WriteLine(message.Status);. Save the file, then run the code again. You should see the status of your message, "queued", printed to your terminal.

If you receive an error in response from Twilio or never receive the message, you may want to check out these tips for troubleshooting undelivered messages.

{"sid": "SMxxxxxxxxxxxxxxx", 
 "date_created": "Thu, 09 Aug 2018 17:26:08 +0000", 
 "date_updated": "Thu, 09 Aug 2018 17:26:08 +0000", 
 "date_sent": null, 
 "account_sid": "ACxxxxxxxxxxxxxxxx", 
 "to": "+15558675310",
 "from": "+15017122661",
 "messaging_service_sid": null,
 "body": "This is the ship that made the Kessel Run in fourteen parsecs?", 
 "status": "queued", 
 "num_segments": "1", 
 "num_media": "0",
 "direction": "outbound-api",
 "api_version": "2010-04-01",
 "price": null,
 "price_unit": "USD",
 "error_code": null,
 "error_message": null,
 "uri": "/2010-04-01/Accounts/ACxxxxxxxxx/Messages/SMxxxxxxxxxxxx.json",
 "subresource_uris": {
     "media": null
 }
}

Send a message to multiple recipients

If you want to send a message to several recipients, you could create an list of recipients (or get a list from a database) and iterate through each phone number in the list:

var numbersToMessage = new List<string>
{
    "+15558675310",
    "+14158141829",
    "+15017122661"
};

foreach (var number in numbersToMessage)
{
    var message = MessageResource.Create(
        body: "Hello from my Twilio number!",
        from: new Twilio.Types.PhoneNumber("+15017122662"),
        to: new Twilio.Types.PhoneNumber(number)
    );

    Console.WriteLine($"Message to {number} has been {message.Status}.");
}

This will create a new Message instance for each phone number in the list.

You can send as many messages as you’d like as quickly as you can and Twilio will queue them up for delivery at your prescribed rate limit.

You may find that it's helpful to organize your account and message logs into separate Messaging Services. See our guide on how to set up and send messages from a messaging service for more tips.

Send a message containing media (MMS) in C# and .NET

To include media in your Twilio-powered text message, you need to make an addition to the code we wrote above. This time, we need to add the mediaUrl parameter.

Again, update the From and To parameters to use your Twilio phone number and your mobile phone.

The new mediaUrl parameter in this code tells Twilio where to go to get the media we want to include. This must be a publicly accessible URL: Twilio will not be able to reach any URLs that are hidden or that require authentication. Note that this parameter accepts a list whereby you can send multiple images. In this example, we only want to send one, so we use the helper Promoter.ListOfOne method from the Twilio.Converters namespace.

Just as when you send a simple SMS, Twilio will send data about the message in its response to your request. The JSON response will contain the unique SID and URI for your media resource:

"subresource_uris": {"media": "/2010-04 01/Accounts/ACxxxxxxxx/Messages/SMxxxxxxxxxxxxx/Media.json"}

When the Twilio REST API creates your new Message resource, it will save the image found at the specified mediaUrl as a Media resource. Once created, you can access this resource at any time via the API.

You can print this value from your .NET code to see where the image is stored. Add the following line to the end of your Program.cs file to see your newly provisioned Media URI:

Console.WriteLine(message.SubresourceUris["media"]);

Save the file and run your project. In just a moment you should receive a text message with an image!

What's next?

You've now successfully sent some messages with the Twilio Programmable SMS API and the Twilio NuGet package.

Check out these in-depth resources to take your programmatic messaging a step further:

• Monitor the status of your message to confirm its delivery.
• Learn how to reply to an SMS sent to your Twilio phone number.
• Learn how to manage message state to turn individual messages into a true SMS conversation.
• Dig into the details with our API reference documentation for Messages.
• Sending high-volume messages? Check out our messaging services.