Send SMS Using Twilio: Comprehensive Guide


In today’s digital age, communication is key, and businesses need reliable methods to reach their customers effectively. One such method is sending SMS, or text messages, which remain a ubiquitous and efficient means of communication. Twilio, a cloud communications platform, offers a powerful solution for sending SMS programmatically, providing businesses with the tools they need to engage with their audience seamlessly. In this article we are discuss how to send SMS using Twilio

What is Twilio?

Twilio is a cloud communications platform that enables developers to integrate various communication methods, including SMS, voice calls, video calls, and more, into their applications and services. It provides APIs and SDKs that simplify the process of incorporating these communication features, making it accessible to developers of all levels.

Send SMS Using Twilio

How Does Twilio Work?

Twilio operates on a pay-as-you-go model, allowing businesses to scale their communication needs according to demand. It provides a range of services, including phone number provisioning, messaging, voice calling, and more, all accessible through its user-friendly interface or pro-grammatically via APIs.

  1. Phone Numbers: Twilio provides a pool of phone numbers across the globe. Developers can acquire a number through Twilio’s API for their application.
  2. APIs (Application Programming Interfaces): These are the building blocks that allow your application to interact with Twilio’s services. Twilio offers various APIs for functionalities like sending and receiving SMS/MMS messages, making and receiving voice calls, and even sending emails.
  3. Signal Processing: When a message or call comes in, Twilio receives it from the carrier network. They have a system in place to interpret that signal.
  4. TwiML (Twilio Markup Language): This is a special language that allows developers to instruct Twilio on how to handle incoming messages and calls. Using TwiML, developers can create a call flow for their application. For instance, they can design an interactive voice response system (IVRS) or route SMS messages to a specific database.
  5. Response: Based on the instructions provided through TwiML, Twilio sends a response – it could be an outgoing message, a voice call, or an email.

Setting Up Twilio

To begin sending SMS using Twilio, you first need to create a Twilio account. Simply visit the Twilio website, sign up for an account, and follow the on-screen instructions to complete the setup process. Once your account is created, you’ll gain access to your Twilio dashboard, where you can manage your communication services.

  1. Account Architecture: Twilio recommends planning how you’ll use their services before diving in. This includes considering:
    • Subaccounts: These act as sub-divisions within your main account, allowing you to manage usage and billing for specific projects or clients.
    • Messaging Services: These group phone numbers and configure how Twilio handles incoming and outgoing messages (SMS, MMS, etc.).
  2. Create Subaccounts and Messaging Services: Once you’ve planned your structure, set up any subaccounts and messaging services you’ll need.
  3. Data Configuration: Twilio offers various ways to handle the data generated through your communication activities. You’ll want to decide on:
    • Webhooks: These are URLs Twilio can send data to when specific events occur (e.g., a message is received). You can set up webhooks at the messaging service or individual phone number level.
    • Log Archives: Twilio can archive data for later retrieval, but this is optional.

Twilio’s API

Twilio’s API provides a comprehensive set of endpoints for sending and receiving SMS, managing phone numbers, handling calls, and more. It offers robust documentation and code examples in various programming languages, making it easy for developers to integrate Twilio into their applications.

  • Messaging API: This API lets you send and receive SMS and MMS messages programmatically. For instance, you can use it to send appointment reminders or shipping notifications. Imagine a bank sending an SMS notification like: “Your account balance is low. Please reply with CONFIRM to avoid service interruption.” This would involve the Messaging API interacting with Twilio’s network to deliver the SMS.
  • Programmable Voice API: This API empowers you to make and receive phone calls through your application. Real estate agents can leverage this to automate follow-up calls with potential clients after they show interest in a property. The API would initiate a call from a Twilio phone number to the client’s number.
  • WhatsApp Business API: This API allows businesses to send and receive messages through WhatsApp. A clothing store can use this to send personalized offers or track order inquiries. They can send a message like: “Hi [Customer Name], Thanks for your recent order! Your order number is #1234. Reply STOP to opt out of marketing messages.” This would be done through the WhatsApp Business API.


Authentication is crucial when using Twilio’s services to ensure the security of your communication. By providing your account SID and authentication token with each request, Twilio can verify the legitimacy of your requests and prevent unauthorized access to your account.

  • Account SID and Auth Token: These are your actual account credentials. The Account SID identifies your account, and the Auth Token grants access to Twilio’s resources. Keep these credentials secure and never share them publicly.
  • Test Credentials: Twilio provides a special set of credentials specifically for testing purposes. You can find these on the Auth Tokens page of your Twilio console. Test credentials allow you to experiment with Twilio’s API without affecting your real account or incurring charges. However, they have limitations:
    • They cannot interact with real phone numbers or other data in your production account.
    • They cannot be used with the Twilio CLI.
    • They are restricted to a specific set of resources for testing (e.g., buying test phone numbers, sending test SMS messages).

Sending SMS with Twilio

Sending SMS with Twilio is straightforward and can be done using its powerful API. After setting up your Twilio account, you’ll need to obtain your account SID and authentication token, which will authenticate your requests to the Twilio API.

Writing the Code: Send SMS Using Twilio

Add Following NameSpaces

using Twilio;
using Twilio.Types;

Write Following code withing the Button Click Event

TwilioClient.Init("AC2d53a77ca6dd92c3b76", "e07d3c0b1dc6912d504");

string mMessage = "";

mMessage = txtMessage.Text;

var message = MessageResource.Create(new PhoneNumber("+1111xxxxxx"), from: new
           PhoneNumber("+111xxxxxx"), body: mMessage);

lblMessage.Text = "SMS Successfully Send";
Send SMS Using Twilio

Handling Responses

It’s essential to handle responses and errors when sending SMS using Twilio. Twilio provides mechanisms for receiving delivery receipts and processing incoming messages, allowing you to track the status of your messages and respond accordingly.

Twilio Pricing

Twilio offers competitive pricing for its SMS services, with charges based on factors such as message volume, destination country, and message type. You can view Twilio’s pricing details on their website or consult their sales team for personalized pricing options.

  • Programmable Voice: This lets you make and receive phone calls through your applications. They charge per minute of call time, with rates starting at $0.0085 per minute for outgoing calls in the US and $0.013 per minute for incoming calls.
  • Programmable Messaging: Similar to voice calls, but for SMS messages. Twilio charges per message sent or received, with prices starting at $0.0075 for sending SMS messages within the US.
  • Programmable Video: Enables video chat functionality within your app. They have two options: Peer-to-Peer (P2P) Rooms billed at $0.0015 per participant minute and Group Rooms billed at $0.004 per participant minute (with different participant capacity limits).
  • Twilio SendGrid Email API: This service integrates with Twilio for sending bulk emails. Their plans are based on the number of contacts you have and emails you send per month. For example, a basic plan starts at $15 per month for 5,000 contacts and 15,000 emails.

It’s important to note that these are just starting prices. Twilio offers volume discounts and other pricing options depending on your specific needs. They also have a free trial available so you can experiment with their services before committing.

Best Practices

To make the most of Twilio’s SMS services, consider implementing the following best practices:

  • Keep messages concise and relevant.
  • Personalize messages whenever possible.
  • Test your SMS campaigns before sending them to a larger audience.
  • Monitor delivery rates and adjust your strategy accordingly.
  • Respect local regulations and guidelines regarding SMS communication.


In conclusion, Twilio provides a reliable and flexible solution for sending SMS programmatically. With its user-friendly interface, robust API, and competitive pricing, Twilio empowers businesses to engage with their audience effectively and drive meaningful communication.


1. Can I send SMS internationally using Twilio? Yes, Twilio supports sending SMS to over 180 countries worldwide. You can check Twilio’s international messaging rates for more details.

2. Is Twilio secure for sending sensitive information via SMS? Twilio takes security seriously and provides encryption and authentication mechanisms to ensure the confidentiality and integrity of your messages.

3. Can I schedule SMS to be sent at a specific time using Twilio? Yes, Twilio allows you to schedule SMS for delivery at a specific date and time using its API or dashboard.

4. Are there any limitations on the length of SMS messages sent via Twilio? Twilio supports standard SMS message lengths of up to 160 characters. Longer messages will be split into multiple parts and may incur additional charges.

5. Does Twilio offer any analytics or reporting features for SMS campaigns? Yes, Twilio provides analytics and reporting tools that allow you to track the performance of your SMS campaigns, including delivery rates, open rates, and more.

Thank you for reading! If you have any further questions or need assistance, feel free to contact us.