Introducing Flask-RESTPlus

Flask is capable of implementing a RESTful interface, but Flask-RESTPlus adds some very interesting capabilities that allow for good developing practices and speed of development:

It defines namespaces, which are ways of creating prefixes and structuring the code. This helps long-term maintenance and helps with the design when creating new endpoints.

If you have more than 10 endpoints in a single namespace, it may be a good time to consider dividing it. Use one namespace per file, and allow the size of the file to hint when it's a good idea to try to make a division.

It has a full solution for parsing input parameters. This means that we have an easy way of dealing with endpoints that requires several parameters and validates them. Using the Request Parsing (https://flask-restplus.readthedocs.io/en/stable/parsing.html) module is similar to using the argparse command-line module (https://docs.python.org/3/library/argparse.html) that's included in the Python standard library. It allows defining arguments in the body of the request, headers, query strings, or even cookies.
In the same way, it has a serialization framework for the resulting objects. Flask-RESTful calls it response marshalling (https://flask-restplus.readthedocs.io/en/stable/marshalling.html). This helps to define objects that can be reused, clarifying the interface and simplifying the development. If enabled, it also allows for field masks, which return partial objects.
It has full Swagger API documentation support. Swagger (https://swagger.io/) is an open source project to help in the design, implementation, documentation, and testing of RESTful API web services, following standard OpenAPI specifications. Flask-RESTPlus automatically generates a Swagger specification and self-documenting page:

The main Swagger documentation page for the Thoughts Backend API, generated automatically

Other nice elements of Flask are derived from the fact that it's a popular project and has a lot of supported tools:

We will use the connector for SQLAlchemy, Flask-SQLAlchemy (https://flask-sqlalchemy.palletsprojects.com/en/2.x/). Its documentation covers most of the common cases, while the SQLAlchemy documentation is more detailed and can be a bit overwhelming.
To run the tests, the pytest-flask module (https://pytest-flask.readthedocs.io/en/latest/) creates some fixtures ready to work with a Flask application. We will talk more about this in the Testing the code section.