Send SMS messages from Azure Functions using the Twilio output binding

3 min to read Contributors
  • Wesley McSwain
  • Glenn Gailey

This article explains how to configure and use Twilio bindings with Azure Functions.

This is reference information for Azure Functions developers. If you're new to Azure Functions, start with the following resources:

Azure Functions supports Twilio output bindings to enable your functions to send SMS text messages with a few lines of code and a Twilio account.

function.json for the Twilio output binding

The function.json file provides the following properties:

  • name : Variable name used in function code for the Twilio SMS text message.
  • type : must be set to "twilioSms".
  • accountSid : This value must be set to the name of an App Setting that holds your Twilio Account Sid.
  • authToken : This value must be set to the name of an App Setting that holds your Twilio authentication token.
  • to : This value is set to the phone number that the SMS text is sent to.
  • from : This value is set to the phone number that the SMS text is sent from.
  • direction : must be set to "out".
  • body : This value can be used to hard code the SMS text message if you don't need to set it dynamically in the code for your function.

Example function.json:

{
  "type": "twilioSms",
  "name": "message",
  "accountSid": "TwilioAccountSid",
  "authToken": "TwilioAuthToken",
  "to": "+1704XXXXXXX",
  "from": "+1425XXXXXXX",
  "direction": "out",
  "body": "Azure Functions Testing"
}

Example C# queue trigger with Twilio output binding

Synchronous

This synchronous example code for an Azure Storage queue trigger uses an out parameter to send a text message to a customer who placed an order.

#r "Newtonsoft.Json"
#r "Twilio.Api"

using System;
using Newtonsoft.Json;
using Twilio;

public static void Run(string myQueueItem, out SMSMessage message,  TraceWriter log)
{
    log.Info($"C# Queue trigger function processed: {myQueueItem}");

    // In this example the queue item is a JSON string representing an order that contains the name of a 
    // customer and a mobile number to send text updates to.
    dynamic order = JsonConvert.DeserializeObject(myQueueItem);
    string msg = "Hello " + order.name + ", thank you for your order.";

    // Even if you want to use a hard coded message and number in the binding, you must at least 
    // initialize the SMSMessage variable.
    message = new SMSMessage();

    // A dynamic message can be set instead of the body in the output binding. In this example, we use 
    // the order information to personalize a text message to the mobile number provided for
    // order status updates.
    message.Body = msg;
    message.To = order.mobileNumber;
}

Asynchronous

This asynchronous example code for an Azure Storage queue trigger sends a text message to a customer who placed an order.

#r "Newtonsoft.Json"
#r "Twilio.Api"

using System;
using Newtonsoft.Json;
using Twilio;

public static async Task Run(string myQueueItem, IAsyncCollector<SMSMessage> message,  TraceWriter log)
{
    log.Info($"C# Queue trigger function processed: {myQueueItem}");

    // In this example the queue item is a JSON string representing an order that contains the name of a 
    // customer and a mobile number to send text updates to.
    dynamic order = JsonConvert.DeserializeObject(myQueueItem);
    string msg = "Hello " + order.name + ", thank you for your order.";

    // Even if you want to use a hard coded message and number in the binding, you must at least 
    // initialize the SMSMessage variable.
    SMSMessage smsText = new SMSMessage();

    // A dynamic message can be set instead of the body in the output binding. In this example, we use 
    // the order information to personalize a text message to the mobile number provided for
    // order status updates.
    smsText.Body = msg;
    smsText.To = order.mobileNumber;

    await message.AddAsync(smsText);
}

Example Node.js queue trigger with Twilio output binding

This Node.js example sends a text message to a customer who placed an order.

module.exports = function (context, myQueueItem) {
    context.log('Node.js queue trigger function processed work item', myQueueItem);

    // In this example the queue item is a JSON string representing an order that contains the name of a 
    // customer and a mobile number to send text updates to.
    var msg = "Hello " + myQueueItem.name + ", thank you for your order.";

    // Even if you want to use a hard coded message and number in the binding, you must at least 
    // initialize the message binding.
    context.bindings.message = {};

    // A dynamic message can be set instead of the body in the output binding. In this example, we use 
    // the order information to personalize a text message to the mobile number provided for
    // order status updates.
    context.bindings.message = {
        body : msg,
        to : myQueueItem.mobileNumber
    };

    context.done();
};

Next steps

For information about other bindings and triggers for Azure Functions, see Azure Functions triggers and bindings developer reference.