No, I'm not. Libraries were certainly used in this case. But whereas in Rails this would be mixing in a library to a controller to allow events and configuring

No, I'm not. Libraries were certainly used in this case. But whereas in Rails this would be mixing in a library to a controller to allow events and configuring them, this was building a new set of models and code over the top of a library for something like Mailgun from no code. A two hour job in Rails/Django/Phoenix but a two week sprint long job to roll your own. Why bother?