Flowable supports NoSQL DBs?

Does Flowable use MongoDB or similar kind of NoSQL databases? Is it possible to access this DB externally.
Our use case would if we can get the Process State from this DB (if its possible) and perform certain custom reporting functionalities.

Flowable Work (Enterprise edition) saves data to an ElasticSearch document store for precisely the use case you mention. Reporting and analytics can be executerd against ElasticSearch without fear of impacting execution of the Flowable engines.