Make a Call

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Warning

To avoid potential issues, we highly suggest that you update your twilio dependency to the latest version before running any of these code samples.

All Functions execute with a pre-initialized instance of the Twilio Node.js SDK available for use. This means you can access and utilize any Twilio SDK method in your Function. For example, you can use a Function to make outbound phone calls via Programmable Voice as we'll show in the following example snippets.

These examples are not exhaustive, and we encourage you to peruse the Programmable Voice documentation for more inspiration on what you can build.

Prerequisites

Before you start, be sure to complete the following prerequisites. You can skip to "Create and host a Function" if you've already completed these steps and need to know more about Function deployment and invocation, or you can skip all the way to "Make an outbound call" if you're all ready to go and want to get straight to the code.

A Twilio account.
A voice-enabled Twilio Phone number.

Create and host a Function

Before you run any of the examples on this page, create a Function and paste the example code into it. You can create a Function in the Twilio Console or by using the Serverless Toolkit.

ConsoleServerless Toolkit

If you prefer a UI-driven approach, complete these steps in the Twilio Console:

Log in to the Twilio Console and navigate to Develop > Functions & Assets. If you're using the legacy Console, open the Functions tab.
Functions are contained within Services. Click Create Service to create a new Service.
Click Add + and select Add Function from the dropdown.
The Console creates a new protected Function that you can rename. The filename becomes the URL path of the Function.
Copy one of the example code snippets from this page and paste the code into your newly created Function. You can switch examples by using the dropdown menu in the code rail.
Click Save.
Click Deploy All to build and deploy the Function. After deployment, you can access your Function at https://<service-name>-<random-characters>-<optional-domain-suffix>.twil.io/<function-path>
For example: test-function-3548.twil.io/hello-world.

You can now invoke your Function with HTTP requests, configure it as the webhook for a Twilio phone number, call it from a Twilio Studio Run Function Widget, and more.

How to invoke your Function

Functions that you create in the UI are protected by default. Set Functions that you deploy with the Serverless Toolkit to protected as well by adding "protected" before the file extension, for example, "send-sms.protected.js". This configuration helps secure your Function and prevents unauthorized access. However, it also adds an extra step when you want to invoke and test the Function manually, as shown in the examples on this page.

To call a protected Function, provide a valid X-Twilio-Signature header in the request. See the documentation for details about the request-validation process.

Generate a valid X-Twilio-Signature header

Though you can generate the header manually with HMAC-SHA1, use the convenience utilities exported by Twilio's SDKs instead. Download the SDK for your preferred language from the libraries page.

After you install the SDK, complete these steps:

Set your Auth Token as an environment variable.
If you use the Node.js example, update the request URL to reference your Service and any query parameters you plan to pass. For other languages, see the examples here.
Run the script and copy the generated X-Twilio-Signature value for use in the next step.

The following sections show how to generate a signature for a POST request with a JSON body and for a GET request that passes data as query parameters:

With a JSON bodyWith Query Parameters

1const { getExpectedTwilioSignature } = require('twilio/lib/webhooks/webhooks');
2
3// Retrieve your auth token from the environment instead of hardcoding
4const authToken = process.env.TWILIO_AUTH_TOKEN;
5
6// Use the Twilio helper to generate your valid signature!
7// The 1st argument is your Twilio auth token.
8// The 2nd is the full URL of your Function.
9// The 3rd is any application/x-www-form-urlencoded data being sent, which is none!
10const xTwilioSignature = getExpectedTwilioSignature(
11  authToken,
12  'https://example-4321.twil.io/sms/send',
13  {} // <- Leave this empty if sending request data via JSON
14);
15
16// Print the signature to the console for use with your
17// preferred HTTP client
18console.log('xTwilioSignature: ', xTwilioSignature);
19
20// For example, the output will look like this:
21// xTwilioSignature: coGTEaFEMv8ejgNGtgtUsbL8r7c=

Create a valid request

After you generate a valid X-Twilio-Signature value, include it as a header in the request to your Function. You can use tools such as curl or Postman. Make sure to do the following:

Set the full URL of the Function, including the root of your Service and the full path to the deployed Function.
Set the X-Twilio-Signature header and content type header (application/json) for your request.
Define the JSON body that you're sending to the Function

Using curl, the request looks like this:

1curl -X POST 'http://test-4321.twil.io/sms/send' \
2  -H 'X-Twilio-Signature: coGTEaFEMv8ejgNGtgtUsbL8r7c=' \
3  -H 'Content-Type: application/json' \
4  --data-raw '{
5    "Body": "Hello, there!"
6  }'

Make an outbound call

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Twilio credentials required

For any Function using the built-in Twilio client, the "Add my Twilio Credentials (ACCOUNT_SID) and (AUTH_TOKEN) to ENV" option on the Settings > Environment Variables tab must be enabled.

You can use a Function to make a call from your Twilio phone number via Programmable Voice. The to and from parameters of your call must be specified to successfully send, and valid TwiML must be provided either via the url or twiml parameters.

You'll tell Twilio which phone number to use to make this call by either providing a From value in your request, or by omitting it and replacing the placeholder default value in the example code with your own Twilio phone number.

Next, specify yourself as the call recipient by either providing a To value in your request, or by omitting it and replacing the default value in the example code with your personal number. The resulting from and to values both must use E.164 formatting ("+" and a country code, e.g., +16175551212).

Finally, the url or twiml value determines the contents of the call that is being sent. As with the other values, either pass in the respective value in your request to this Function or override the default in the example to your own custom value.

Once you've made any modifications to the sample and have deployed your Function for testing, go ahead and make some test HTTP requests against it to get a call to your phone! Example code for invoking your Function is described earlier in this document.

Make an outbound call

Twilio will retrieve the TwiML from the provided URL and use it to handle the call

1exports.handler = function (context, event, callback) {
2  // The pre-initialized Twilio client is available from the `context` object
3  const twilioClient = context.getTwilioClient();
4
5  // Query parameters or values sent in a POST body can be accessed from `event`
6  const from = event.From || '+15017122661';
7  const to = event.To || '+15558675310';
8  // Note that TwiML can be hosted at a URL and accessed by Twilio
9  const url = event.Url || 'http://demo.twilio.com/docs/voice.xml';
10
11  // Use `calls.create` to place a phone call. Be sure to chain with `then`
12  // and `catch` to properly handle the promise and call `callback` _after_ the
13  // call is placed successfully!
14  twilioClient.calls
15    .create({ to, from, url })
16    .then((call) => {
17      console.log('Call successfully placed');
18      console.log(call.sid);
19      // Make sure to only call `callback` once everything is finished, and to pass
20      // null as the first parameter to signal successful execution.
21      return callback(null, `Success! Call SID: ${call.sid}`);
22    })
23    .catch((error) => {
24      console.error(error);
25      return callback(error);
26    });
27};

Make an outbound call

Directly provide TwiML instructions for how to handle the call

1exports.handler = function (context, event, callback) {
2  // The pre-initialized Twilio client is available from the `context` object
3  const twilioClient = context.getTwilioClient();
4
5  // Query parameters or values sent in a POST body can be accessed from `event`
6  const from = event.From || '+15017122661';
7  const to = event.To || '+15558675310';
8  // Note that the provided TwiML can be serialized as a string and sent!
9  const twiml = event.Twiml || '<Response><Say>Ahoy there!</Say></Response>';
10
11  // Use `calls.create` to place a phone call. Be sure to chain with `then`
12  // and `catch` to properly handle the promise and call `callback` _after_ the
13  // call is placed successfully!
14  twilioClient.calls
15    .create({ to, from, twiml })
16    .then((call) => {
17      console.log('Call successfully placed');
18      console.log(call.sid);
19      // Make sure to only call `callback` once everything is finished, and to pass
20      // null as the first parameter to signal successful execution.
21      return callback(null, `Success! Call SID: ${call.sid}`);
22    })
23    .catch((error) => {
24      console.error(error);
25      return callback(error);
26    });
27};

Record an outbound call

When making an outgoing call, you can tell Twilio to record the entire call from beginning to end. Add the record argument to your call to calls.create(), set it to true, and Twilio will record the full call on your behalf.

Once the call is complete, you can listen to your recordings either in the Twilio Console, or access them directly via the REST API for Recordings.

Record an outbound call

1exports.handler = function (context, event, callback) {
2  // The pre-initialized Twilio client is available from the `context` object
3  const twilioClient = context.getTwilioClient();
4
5  // Query parameters or values sent in a POST body can be accessed from `event`
6  const from = event.From || '+15017122661';
7  const to = event.To || '+15558675310';
8  // Note that TwiML can be hosted at a URL and accessed by Twilio
9  const url = event.Url || 'http://demo.twilio.com/docs/voice.xml';
10
11  // Use `calls.create` to place a phone call. Be sure to chain with `then`
12  // and `catch` to properly handle the promise and call `callback` _after_ the
13  // call is placed successfully!
14  // Note the addition of the `record` configuration flag for `calls.create`
15  twilioClient.calls
16    .create({ to, from, record: true, url })
17    .then((call) => {
18      console.log('Call successfully placed');
19      console.log(call.sid);
20      // Make sure to only call `callback` once everything is finished, and to pass
21      // null as the first parameter to signal successful execution.
22      return callback(null, `Success! Call SID: ${call.sid}`);
23    })
24    .catch((error) => {
25      console.error(error);
26      return callback(error);
27    });
28};

Make a Call

Warning

Prerequisites

Create and host a Function

Run your Function in local development

Deploy your Function

How to invoke your Function

Generate a valid X-Twilio-Signature header

Create a valid request

Create a valid request

Make an outbound call

Twilio credentials required

Make an outbound call

Make an outbound call

Record an outbound call

Record an outbound call