index.js

var http = require('http');
var twilio = require('twilio');
var qs = require('querystring');

http.createServer(function (req, res) {
  var body = '';
  req.setEncoding('utf8');

  req.on('data', function(data) {
    body += data;
  });

  req.on('end', function() {
    var data = qs.parse(body);
    var jsonString = JSON.stringify(data);
    var jsonDataObject = JSON.parse(jsonString);

    // log the received message
    console.log(jsonDataObject.Body);

    var twiml = new twilio.TwimlResponse();
    twiml.message("Hello world");

    res.writeHead(200, {'Content-Type': 'text/xml'});
    res.end(twiml.toString());
  });

}).listen(1337, '127.0.0.1');

console.log('TwiML servin\' server running at http://127.0.0.1:1337/');

package.json

{
  "name": "stackoverflowtest",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "querystring": "^0.2.0",
    "twilio": "^2.5.2"
  }
}