Normalize telephone numbers
Twilio's APIs consistently use the E.164 standard for phone numbers. This format is fine within your code, but it presents a couple of user-facing issues:
- E.164 is difficult to understand when presented as plain text, such as in an SMS
-
When read aloud by a Twilio
Say verb
or
Say Widget
, numbers such as
+15095550100will be read literally as a large number, instead of digit-by-digit. (ex. "Plus fifteen billion, ninety-five million, five hundred fifty thousand, one hundred")
Fortunately, Twilio Lookup enables you to convert a given E.164 phone number into the national format used by that country, which Twilio will read aloud as one would normally say it in their region.
To get started, use the following instructions to create a Function to host your code.
In order to run any of the following examples, you will first need to create a Function into which you can paste the example code. You can create a Function using the Twilio Console or the Serverless Toolkit as explained below:
If you prefer a UI-driven approach, creating and deploying a Function can be done entirely using the Twilio Console and the following steps:
- Log in to the Twilio Console and navigate to the Functions tab . If you need an account, you can sign up for a free Twilio account here !
- Functions are contained within Services . Create a Service by clicking the Create Service button and providing a name such as test-function .
- Once you've been redirected to the new Service, click the Add + button and select Add Function from the dropdown.
- This will create a new Protected Function for you with the option to rename it. The name of the file will be path it is accessed from.
- Copy any one of the example code snippets from this page that you want to experiment with, and paste the code into your newly created Function. You can quickly switch examples by using the dropdown menu of the code rail.
- Click Save to save your Function's contents.
-
Click
Deploy All
to build and deploy the Function. After a short delay, your Function will be accessible from:
https://<service-name>-<random-characters>-<optional-domain-suffix>.twil.io/<function-path>
For example:test-function-3548.twil.io/hello-world.
Your Function is now ready to be invoked by HTTP requests, set as the webhook of a Twilio phone number, invoked by a Twilio Studio Run Function Widget, and more!
The following Function is one which will tell the user their phone number, in the format that they would expect in normal conversation. This will also work for international phone numbers!
To verify this for yourself, paste the code into the Function that you just made, and set it as the A Call Comes In webhook handler for the Twilio phone number you wish to test. The following instructions will show you how to do so.
_18exports.handler = async (context, event, callback) => {_18 // The pre-initialized Twilio client is available from the `context` object_18 const client = context.getTwilioClient();_18 // Create a new voice response object_18 const twiml = new Twilio.twiml.VoiceResponse();_18_18 // The From value is provided by Twilio to this webhook Function, and contains the caller's_18 // phone number in E.164 format, ex. '+15095550100'_18 const from = event.From;_18_18 // Call Twilio Lookup to get information about the number, including its national format_18 const result = await client.lookups.phoneNumbers(from).fetch();_18_18 // Read back the caller's phone number in the way it would normally spoken, not as a_18 // massive integer!_18 twiml.say(`Your phone number is ${result.nationalFormat}`);_18 return callback(null, twiml);_18};
In order for your Function to react to incoming SMS and/or voice calls, it must be set as a webhook for your Twilio number. There are a variety of methods to set a Function as a webhook, as detailed below:
You can use the Twilio Console UI as a straightforward way of connecting your Function as a webhook:
- Log in to the Twilio Console's Phone Numbers page .
- Click on the phone number you'd like to have connected to your Function.
- If you want the Function to respond to incoming SMS, find the A Message Comes In option under Messaging . If you want the Function to respond to Voice, find the A Call Comes In option under Voice & Fax .
- Select Function from the A Message Comes In or A Call Comes In dropdown.
-
Select the
Service
that you are using, then the
Environment
(this will default to
uiunless you have created custom domains ), and finally Function Path of your Function from the respective dropdown menus.