server.example

const AccessToken = require('twilio').jwt.AccessToken;
const VoiceGrant = AccessToken.VoiceGrant;

// Used when generating any kind of tokens
// To set up environmental variables, see http://twil.io/secure

// Used specifically for creating Voice tokens

const outgoingApplicationSid = 'APd03584f63d77249726a31e44e315398';
const identity = 'user';

// Create a "grant" which enables a client to use Voice as a given user
const voiceGrant = new VoiceGrant({
  outgoingApplicationSid: outgoingApplicationSid,
  incomingAllow: true, // Optional: add to allow incoming calls
});

console.log(voiceGrant)

// Create an access token which we will sign and return to the client,
// containing the grant we just created
const token = new AccessToken(
  twilioAccountSid,
  twilioApiKey,
  twilioApiSecret,
  {identity: identity}
);
token.addGrant(voiceGrant);

// Serialize the token to a JWT string
console.log(token.toJwt());