Javascript SDK for Twilio Client

Usage no npm install needed!

<script type="module">
  import flmcatSip from 'https://cdn.skypack.dev/flmcat-sip';


Twilio is currently running a public pilot phase for 2.0!

This repository is the current stable version of Twilio's Javascript Client SDK. We recently released a 2.0 pilot to gather customer feedback. In this phase, it is possible that some aspects of the 2.0 API may change before GA. If you're interested in trying it out, see the 2.0 pilot version of the SDK.

This new major version cleans up a lot of the legacy API, such as:

  • Removing deprecated methods
  • Renaming classes and methods to be less ambiguous
  • Implementing the new features from 1.x as defaults rather than behind feature flags
  • Completely moving to the new TwilioError class which is standardized between Voice SDKs and contains much more detailed information about errors

Additionally, new features from this point onward will only be added to the 2.0 project, and not be backported to 1.x, so anyone looking to use the latest features will want to be moved to the new 2.0 API.


Travis Build Status NPM

twilio-client.js allows you to add real-time voice and PSTN calling to your web apps.

Technical Support

If you need technical support, contact help@twilio.com.



We recommend using npm to add the Client SDK as a dependency.

npm install twilio-client --save

Using this method, you can import twilio-client.js using ES Module or TypeScript syntax:

import { Device } from 'twilio-client';

Or using CommonJS:

const Device = require('twilio-client').Device;


Though not recommended, releases of twilio-client.js are also hosted on a CDN and you can include these directly in your web app using a <script> tag.

<script src="https://sdk.twilio.com/js/client/v1.14/twilio.js"></script>

Using this method, twilio-client.js will set a browser global:

const Device = Twilio.Device;


Running unit tests requires no setup aside from installation (above). You can run unit tests via:

npm run test:unit

Integration tests require some set up:

  1. If the account you want to use doesn't already have a TwiML app set up, create one using the TwiML code below.
  2. Copy config.example.yaml to config.yaml, replacing the placeholder information with valid credentials.
<?xml version="1.0" encoding="UTF-8"?>
      <Parameter name="duplicate" value="12345" />
      <Parameter name="duplicate" value="123456" />
      <Parameter name="custom + param" value="ζˆ‘δΈεƒθ›‹" />
      <Parameter name="foobar" value="some + value" />
      <Parameter name="custom1" value="{{Custom1}}" />
      <Parameter name="custom2" value="{{Custom2}}" />
      <Parameter name="custom3" value="{{Custom3}}" />

Integration tests can be run via:

npm run test:integration

These tests will run via karma, one at a time, in your system's default Chrome and then Firefox.

Content Security Policy (CSP)

Use the following policy directives to enable CSP that is compatible with twilio-client.js.

script-src https://media.twiliocdn.com https://sdk.twilio.com
media-src mediastream https://media.twiliocdn.com https://sdk.twilio.com
connect-src https://eventgw.twilio.com wss://chunderw-vpc-gll.twilio.com https://media.twiliocdn.com https://sdk.twilio.com

If you are providing a non-default value for Device.Options.edge or Device.Options.region parameter, you need to add the Signaling URI wss://chunderw-vpc-gll-{regionId}.twilio.com in your connect-src directive where regionId is the Region ID as defined in this page. See examples below.

If Device.Options.region is us1

connect-src https://eventgw.twilio.com https://media.twiliocdn.com https://sdk.twilio.com wss://chunderw-vpc-gll-us1.twilio.com

If Device.Options.edge is ashburn

connect-src https://eventgw.twilio.com https://media.twiliocdn.com https://sdk.twilio.com wss://chunderw-vpc-gll-us1.twilio.com

If Device.Options.edge is ['ashburn', 'sydney', 'roaming']

connect-src https://eventgw.twilio.com https://media.twiliocdn.com https://sdk.twilio.com wss://chunderw-vpc-gll-us1.twilio.com wss://chunderw-vpc-gll-au1.twilio.com wss://chunderw-vpc-gll.twilio.com