I have a friend who is the Chief Technical Officer (CTO) in a Financial Technology (FinTech) start-up that provides a proprietary Software with a Service (SwaS). When he defined their product, a relational database was a natural fit as the backend for their application, so he chose PostgreSQL.

However, as their strategy, goals and product evolved, my friend realised that their application needed a plastic data model, which a relational database can’t provide, so they must migrate to a NoSQL data store.

I have been supporting my friend on the architecture and planning for this migration. Here you have a cookbook that describes the process I followed in choosing the right NoSQL database as per this FinTech requirements, proposes an architecture for this SwaS based on MongoDB (the target database), and explains how to migrate.