# app.js This file is the conventional entry point for a _production_ Sails/Node.js app. When developing on your local computer, and you run `sails lift`, the code in `app.js` is not executed. Instead, this file exists to provide an easy, out-of-the-box way to run your app _without_ typing `sails lift`. This is most likely how you'll start your app in production (i.e. `node app`, or `npm start`). For example, when you deploy to most PaaS vendors like [Heroku](http://heroku.com), they will automatically detect that you're running a Sails/Node.js app and execute this file with the `NODE_ENV` environment variable set to production. > Whatever stage of the development lifecycle you're at, you can safely ignore `app.js`. It's good to go out of the box for most apps. But the code in `app.js` also serves as an easy-to-reference example of how to use Sails programmatically. So you might want to take a look at it if you plan on writing automated tests, scheduled jobs, manual database migrations, or administration scripts.