Voice JavaScript SDK: Twilio in the browser
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You're viewing the documentation for the 2.X version of the Voice JavaScript SDK. View the Migration Guide to learn how to migrate from 1.X to 2.X or view the 1.x-specific documentation.
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The Twilio Client JavaScript SDK has been renamed to Twilio Voice JavaScript SDK.
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When using the Voice Javascript SDK with Twilio Regions, please make sure the SDK version is updated to at least 2.1.0
The Twilio Voice JavaScript SDK allows you to make voice calls to and from a web browser and a Twilio TwiML Voice Application. This means you can open inbound and outbound audio connections to Twilio for building softphones, walkie-talkies, conference calls, click-to-talk systems, and more, all from the browser.
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Want to get started right away? Jump right in with one of our Voice JavaScript SDK Quickstarts.
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Intending to write back-end JavaScript with Twilio in Node.js to support your front-end client? Check out the Twilio Node.js SDK.
You set up your device and establish a connection to Twilio. Audio from your device's microphone is sent to Twilio, and Twilio sends back audio which is played through your device's speakers, like on a normal phone call. The key difference is that with Twilio Voice JavaScript SDK, your "phone" is a Twilio.Device, a "soft device" that provides connections into Twilio.
_10npm install @twilio/voice-sdk --save
Using this method, you can import the Voice SDK using ES Module or TypeScript syntax:
_10import { Device } from '@twilio/voice-sdk';
Or using CommonJS:
_10const Device = require('@twilio/voice-sdk').Device;
As of 2.0, the Twilio Voice SDK is no longer hosted via CDN.
Although we recommend using npm to add the Voice SDK as a dependency, you can also get the Twilio Voice SDK code from GitHub and include it in your project directly. To do so, navigate to "Releases" and find the most recent release, or the particular release version you'd like to use.
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Releases tagged with "-rc" are "Release Candidate" versions and are still being tested. Unless you specifically know that you want to use a release candidate version, you should not use a release with "-rc" in the name.
Download either the zip or the tar.gz and then extract the files. For example, if you downloaded the tarball for the 2.0.0 release, you could then extract the files with the tar command:
_10tar -xvzf twilio-voice.js-2.0.0.tar.gz_10cd twilio-voice.js-2.0.0
Once you've extracted the folder, the twilio.js and twilio.min.js files that you can include in your project will be in the /dist directory. twilio.min.js is the minified version of the code.
You can copy either the twilio.js or the twilio.min.js file into your project and then provide a link to it in your html. For example:
_10<script type="text/javascript" src="twilio.min.js"></script>
Using this method, you can access the SDK through the browser global:
_10const Device = Twilio.Device;
The following table indicates the browsers supported by the Twilio Voice JavaScript SDK. We support the most recent (N) and the two previous (N-2) versions of these browsers unless otherwise indicated.
| Chrome | Firefox | Safari* | Edge** | |
|---|---|---|---|---|
| Android | ✓ | ✓ | ||
| iOS | ✓ | ✓ | ✓ | |
| Linux | ✓ | ✓ | ||
| macOS | ✓ | ✓ | ✓ | |
| Windows | ✓ | ✓ | ✓ |
* WebRTC support in Safari started with Safari version 11.
** We support Chromium-based Edge only. Legacy Edge isn't supported. See this advisory for more details.
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Mobile browsers lack the ability to receive or maintain call connectivity whilst in the background and they do not allow GSM call interruption handling. These lead to poor user experience. To create the best user experience, Twilio recommends understanding these limitations when creating mobile Voice Applications. Twilio also recommends evaluating the iOS and Android SDKs for creating mobile Voice Applications.
Twilio Voice JavaScript SDK is also supported on the latest Electron version
| Channel | Type |
|---|---|
| Signaling | TLS (Secure Web Socket) |
| Media | DTLS-SRTP (AES_CM_128_HMAC_SHA1_80) |
As of version 1.3, Twilio Voice JavaScript SDK (formerly known as Twilio Client JS SDK) has been strictly following semantic versioning: minor-level updates only contain feature updates and are completely backward compatible with 1.3.0 and newer.
Support for twilio.js 1.1 and 1.2 ceased on February 14, 2018. If you are still using either of these versions, please use the Migration Guide to upgrade to the latest version.