Ruby on Rails vs Rails on Rails?

In general, you are free to not call api is that you don't need. I think the performance characteristics between these frameworks for the same language end up being pretty close. Unless you truly know, five years from now, that you're not going to need 99 % of the features of like a jango or rails, then maybe i make sense for you to write something in sonatra. But don't see that used case actually happening in reality often enough.