Twilio.js 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.
You setup your device and establish a connection to Twilio. Audio from your device's microphone is sent to Twilio, and Twilio plays audio through your device's speakers, like on a normal phone call. But with Twilio Client, your device need not be a phone.
When you initiate a connection using Twilio Client, you're not connecting to another phone directly. Rather, you're connecting to Twilio and instructing Twilio to fetch TwiML from your server to handle the connection. This is analogous to the way Twilio handles incoming calls from a real phone. All the same TwiML verbs and nouns that are available for handling Twilio Voice calls are also available for handling Twilio Client connections. We've also added a new
<Client> noun for dialing to a Client.
Because Twilio Client connections aren't made to a specific phone number, Twilio relies on a Twilio Application within your account to determine how to interact with your server. A Twilio Application is just a convenient way to store a set of URLs, like the
SmsUrl on a phone number, but without locking them to a specific phone number. This makes Twilio Applications perfect for handling connections from Twilio Client (which is actually why we created them in the first place).
So when your device initiates a Twilio Client connection to Twilio, a request is made to the
VoiceUrl property of an Application within your account. You specify the Application you're connecting to with a Capability Token. Twilio uses the TwiML response from its request to that Application's
VoiceUrl to direct what happens with the Client connection.
Twilio.js is currently available under the following releases:
The following older releases of twilio.js are deprecated. Customers are strongly encouraged to upgrade to twilio.js 1.4. We have provided a detailed Migration Guide to assist with the upgrade:
Please use the Migration Guide to upgrade to twilio.js 1.4.
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