Domain Driven Design:
Class models with validation and serialization
The Toasted Marshmallow Enum package makes it possible to dump and load Enum values based on the ultra fast serialization that Toasted Marshmallow provides.
The Flask JSON API package provides boilerplate code for setting up REST based apps.
Flask JSON Content-Type decorator which validates that the Content-Type is indeed application/json. In the case of a wrong content type, then the decorator will throw an exception which can be customized.