api.js

var express = require("express");

// Create the API application.
var api = express();

api.get("/v1/money", function(req, res) {
  res.json({ "bling": "$$$" });
});

module.exports = api;

app.js

var express = require("express");

// Create the main application.
var app = express();

// Mount the API express app on `/api`.
app.use("/api", require("./api"));

// Send some strings.
app.get("/", function(req, res) {
  res.send("Hello world!");
});

// Listen here.
app.listen(8080, "127.0.0.1");