package-lock.json is not required but is recommended to ensure consistency of your dependencies.

Specify how to start your app

To determine how to start your app, Backery first looks for a Procfile. If no Procfile exists for a Node.js app, we will attempt to start a default web process via the start script in your package.json.

Your app must bind to the port number specified in the PORT environment variable. If it does not the app will not start.