This is the basic structure to create a node server with express.

server.js

var express = require('express');
var app = express();

app.get('/', function(request, response) {
  response.send('<h1>Hello World!</h1>');
});

var port = process.env.PORT || 1337;

app.listen(port, function() {
  console.log('Server working on http://localhost:' + port);
});