# Make a Call

> \[!WARNING]
>
> To avoid potential issues, we highly suggest that you [update your twilio dependency to the latest version](/docs/serverless/functions-assets/functions/dependencies#staying-up-to-date) 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](/docs/voice) as we'll show in the following example snippets.

These examples are not exhaustive, and we encourage you to peruse the [Programmable Voice](/docs/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](/docs/serverless/functions-assets/quickstart/make-a-call#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](/docs/serverless/functions-assets/quickstart/make-a-call#make-an-outbound-call)" if you're all ready to go and want to get straight to the code.

* **A [Twilio account](https://www.twilio.com/try-twilio).**
* **A voice-enabled [Twilio Phone number](https://www.twilio.com/console/phone-numbers/search).**

## Create and host a Function

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](/docs/labs/serverless-toolkit) as explained below:

## Console

If you prefer a UI-driven approach, creating and deploying a Function can be done entirely using the Twilio Console and the following steps:

1. Log in to the Twilio Console and navigate to the [Functions tab](https://www.twilio.com/console/functions/overview). If you need an account, you can sign up for a free Twilio account [here](https://www.twilio.com/try-twilio)!
2. Functions are contained within **Services**. Create a **[Service](/docs/serverless/functions-assets/functions/create-service)** by clicking the **[Create Service](https://www.twilio.com/console/functions/overview/services)** button and providing a name such as *test-function*.
3. Once you've been redirected to the new Service, click the **Add +** button and select **Add Function** from the dropdown.
4. This will create a new [Protected](/docs/serverless/functions-assets/visibility) Function for you with the option to rename it. The name of the file will be path it is accessed from.
5. 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.
6. Click **Save** to save your Function's contents.
7. 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`.

## Serverless Toolkit

The [Serverless Toolkit](/docs/labs/serverless-toolkit) enables you with local development, project deployment, and other functionality via the [Twilio CLI](/docs/twilio-cli/quickstart). To get up and running with these examples using Serverless Toolkit, follow this process:

1. From the CLI, run `twilio serverless:init <your-service-name> --empty` to bootstrap your local environment.
2. Navigate into your new project directory using `cd <your-service-name>`
3. In the `/functions` directory, create a new JavaScript file that is named respective to the purpose of the Function. For example, `sms-reply.protected.js` for a [Protected](/docs/serverless/functions-assets/visibility) Function intended to handle incoming SMS.
4. Populate the file using the code example of your choice and save. **Note** A Function can only export a single handler. You will want to create separate files if you want to run and/or deploy multiple examples at once.

Once your Function(s) code is written and saved, you can test it either by running it locally (and optionally tunneling requests to it via a tool like [ngrok](https://ngrok.com/)), or by deploying the Function and executing against the deployed url(s).

### Run your Function in local development

Run `twilio serverless:start` from your CLI to start the project locally. The Function(s) in your project will be accessible from `http://localhost:3000/sms-reply`

* If you want to test a Function as a [Twilio webhook](/docs/usage/webhooks/getting-started-twilio-webhooks), run: `twilio phone-numbers:update <your Twilio phone number> --sms-url "http://localhost:3000/sms-reply"`\
  This will automatically generate an ngrok tunnel from Twilio to your locally running Function, so you can start sending texts to it. You can apply the same process but with the `voice-url` flag instead if you want to test with [Twilio Voice](/docs/voice).
* If your code does *not* connect to Twilio Voice/Messages as a webhook, you can start your dev server and start an ngrok tunnel in the same command with the `ngrok` flag. For example: `twilio serverless:start --ngrok=""`

### Deploy your Function

To deploy your Function and have access to live url(s), run `twilio serverless:deploy` from your CLI. This will deploy your Function(s) to Twilio under a development environment by default, where they can be accessed from:

`https://<service-name>-<random-characters>-dev.twil.io/<function-path>`

For example: `https://incoming-sms-examples-3421-dev.twil.io/sms-reply`

Your Function is now ready to be invoked by HTTP requests, set as the [webhook](/docs/usage/webhooks/getting-started-twilio-webhooks) of a Twilio phone number, invoked by a Twilio Studio **[Run Function Widget](/docs/studio/widget-library/run-function)**, and more!

## How to invoke your Function

Functions created in the UI are [Protected](/docs/serverless/functions-assets/visibility) by default, and we highly recommend you to set Functions deployed via the Serverless Toolkit to `protected` as well by prepending `protected` before the file extension, for example: `send-sms.protected.js`. This will help secure your Function and protect it from being accessed by bad actors. However, this also adds an extra layer of complexity if you want to manually invoke and test code, such as the examples on this page.

In order to successfully call your `protected` Function, you will need to provide a valid `X-Twilio-Signature` header in your request. You can learn more about the [request validation process](/docs/usage/security#validating-requests), but in the meantime, let's get started with some code that will get you up and running fast.

### Generate a valid X-Twilio-Signature header

While it's possible to generate the header yourself using [HMAC-SHA1](/docs/usage/security#a-note-on-hmac-sha1), we highly recommend you use the convenience utilities exported by [Twilio's SDKs](/docs/libraries) to perform this operation. Head over to the [libraries page](/docs/libraries) to download the library for your language of choice.

Once you have the library of your choice installed, you'll need to:

1. Set your [Auth Token](https://www.twilio.com/console) as an [environment variable](/docs/usage/secure-credentials).
2. Modify the URL of the example below to match your Service and any intended data that you want to communicate as query parameters, if any, if using Node.js. (Refer to the examples [here](/docs/usage/security#test-the-validity-of-your-webhook-signature) for how to generate a signature with other SDKs.)
3. Execute the modified script and save the resulting `X-Twilio-Signature` for use in the next step.

Here are two examples for if you want to generate a signature for a `POST` request which includes JSON, or a `GET` request that communicates its data as query parameters instead:

## With a JSON body

```javascript
const { getExpectedTwilioSignature } = require('twilio/lib/webhooks/webhooks');

// Retrieve your auth token from the environment instead of hardcoding
const authToken = process.env.TWILIO_AUTH_TOKEN;

// Use the Twilio helper to generate your valid signature!
// The 1st argument is your Twilio auth token.
// The 2nd is the full URL of your Function.
// The 3rd is any application/x-www-form-urlencoded data being sent, which is none!
const xTwilioSignature = getExpectedTwilioSignature(
  authToken,
  'https://example-4321.twil.io/sms/send',
  {} // <- Leave this empty if sending request data via JSON
);

// Print the signature to the console for use with your
// preferred HTTP client
console.log('xTwilioSignature: ', xTwilioSignature);

// For example, the output will look like this:
// xTwilioSignature: coGTEaFEMv8ejgNGtgtUsbL8r7c=
```

### Create a valid request

Once you've generated a valid `X-Twilio-Signature` value, it's time to use this as a header in a request to your Function. You can do so using a variety of tools, such as [curl](https://curl.se/), [Postman](https://www.postman.com/), and more. Be sure to:

* Set the 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 example request above would look like this:

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

## With Query Parameters

```javascript
const { getExpectedTwilioSignature } = require('twilio/lib/webhooks/webhooks');

// Retrieve your auth token from the environment instead of hardcoding
const authToken = process.env.TWILIO_AUTH_TOKEN;

// Use the Twilio helper to generate your valid signature!
// The 1st argument is your Twilio auth token.
// The 2nd is the full URL of your Function including query params.
// The 3rd is any application/x-www-form-urlencoded data being sent, which is none!
const xTwilioSignature = getExpectedTwilioSignature(
  authToken,
  'https://example-4321.twil.io/sms/send?Body=hello',
  {} // <- Leave this empty
);

// Print the signature to the console for use with your
// preferred HTTP client
console.log('xTwilioSignature: ', xTwilioSignature);

// For example, the output will look like this:
// xTwilioSignature: a610Oi5WiDIHNrUsQYUvNCxKv7A=
```

### Create a valid request

Once you've generated a valid `X-Twilio-Signature` value, it's time to use this as a header in a request to your Function. You can do so using a variety of tools, such as [curl](https://curl.se/), [Postman](https://www.postman.com/), and more. Be sure to:

* Set the URL of the Function, including the root of your Service, the full path to the deployed Function, and your query parameters.
* Set the `X-Twilio-Signature` header for your request.

Using curl, the example request above would look like this:

```bash
curl -X GET 'http://test-4321.twil.io/sms/send?Body=hello' \
  -H 'X-Twilio-Signature: a610Oi5WiDIHNrUsQYUvNCxKv7A='
```

## Make an outbound call

> \[!WARNING]
>
> 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](/docs/voice). The `to` and `from` parameters of your call must be specified to successfully send, and valid [TwiML](/docs/glossary/what-is-twilio-markup-language-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](/docs/glossary/what-e164) ("`+`" 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](/docs/serverless/functions-assets/quickstart/make-a-call#how-to-invoke-your-function) is described earlier in this document.

```js title="Make an outbound call" description="Twilio will retrieve the TwiML from the provided URL and use it to handle the call"
exports.handler = function (context, event, callback) {
  // The pre-initialized Twilio client is available from the `context` object
  const twilioClient = context.getTwilioClient();

  // Query parameters or values sent in a POST body can be accessed from `event`
  const from = event.From || '+15017122661';
  const to = event.To || '+15558675310';
  // Note that TwiML can be hosted at a URL and accessed by Twilio
  const url = event.Url || 'http://demo.twilio.com/docs/voice.xml';

  // Use `calls.create` to place a phone call. Be sure to chain with `then`
  // and `catch` to properly handle the promise and call `callback` _after_ the
  // call is placed successfully!
  twilioClient.calls
    .create({ to, from, url })
    .then((call) => {
      console.log('Call successfully placed');
      console.log(call.sid);
      // Make sure to only call `callback` once everything is finished, and to pass
      // null as the first parameter to signal successful execution.
      return callback(null, `Success! Call SID: ${call.sid}`);
    })
    .catch((error) => {
      console.error(error);
      return callback(error);
    });
};
```

```js title="Make an outbound call" description="Directly provide TwiML instructions for how to handle the call"
exports.handler = function (context, event, callback) {
  // The pre-initialized Twilio client is available from the `context` object
  const twilioClient = context.getTwilioClient();

  // Query parameters or values sent in a POST body can be accessed from `event`
  const from = event.From || '+15017122661';
  const to = event.To || '+15558675310';
  // Note that the provided TwiML can be serialized as a string and sent!
  const twiml = event.Twiml || '<Response><Say>Ahoy there!</Say></Response>';

  // Use `calls.create` to place a phone call. Be sure to chain with `then`
  // and `catch` to properly handle the promise and call `callback` _after_ the
  // call is placed successfully!
  twilioClient.calls
    .create({ to, from, twiml })
    .then((call) => {
      console.log('Call successfully placed');
      console.log(call.sid);
      // Make sure to only call `callback` once everything is finished, and to pass
      // null as the first parameter to signal successful execution.
      return callback(null, `Success! Call SID: ${call.sid}`);
    })
    .catch((error) => {
      console.error(error);
      return callback(error);
    });
};
```

## 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](https://www.twilio.com/console/voice/logs/recordings), or access them directly via the REST API for [Recordings](/docs/voice/api/recording).

```js title="Record an outbound call"
exports.handler = function (context, event, callback) {
  // The pre-initialized Twilio client is available from the `context` object
  const twilioClient = context.getTwilioClient();

  // Query parameters or values sent in a POST body can be accessed from `event`
  const from = event.From || '+15017122661';
  const to = event.To || '+15558675310';
  // Note that TwiML can be hosted at a URL and accessed by Twilio
  const url = event.Url || 'http://demo.twilio.com/docs/voice.xml';

  // Use `calls.create` to place a phone call. Be sure to chain with `then`
  // and `catch` to properly handle the promise and call `callback` _after_ the
  // call is placed successfully!
  // Note the addition of the `record` configuration flag for `calls.create`
  twilioClient.calls
    .create({ to, from, record: true, url })
    .then((call) => {
      console.log('Call successfully placed');
      console.log(call.sid);
      // Make sure to only call `callback` once everything is finished, and to pass
      // null as the first parameter to signal successful execution.
      return callback(null, `Success! Call SID: ${call.sid}`);
    })
    .catch((error) => {
      console.error(error);
      return callback(error);
    });
};
```