main.js

// Use Parse's RPC functionality to make an outbound call
Parse.Cloud.define('makeCall', function(request, response) {
    // Create a Twilio REST API client - get your account SID and
    // auth token at https://www.twilio.com/user/account
    var client = new twilio.RestClient(
        'YOUR_ACCOUNT_SID', // Account SID
        'YOUR_AUTH_TOKEN' // auth token
    );

    // Place an outbound call
    client.makeCall({
        to: request.params.to, // the number you wish to call
        from: '+16515557777', // a valid Twilio number you own
        url: 'https://chunky-danger-monkey.parseapp.com/hello', // TwiML URL
        method: 'GET' // HTTP method with which to fetch the TwiML
    }, function(error, data) {
        // Handle the result of placing the outbound call
        if (error) {
            response.error('there was a problem :(');
        } else {
            response.success('call incoming!');
        }
    });
});