Though Node has many framework to help you getting your server up and running, mainly:
Express: The most used framework
Total: The ALL-IN-ONE UNITY framework, that have everything and do not depend on any other framework or module.
But, there is always no one size fits all, so developer may need to build his/her own server, without any other dependency.
If the app i accessed through external server, CORS could be an issue, a code to avoid it had been provided.