Our team recently did something similar. We went from MongoDB to PostgreSQL. We converted most of our well known fields over to proper PostgreSQL fields, and

Our team recently did something similar. We went from MongoDB to PostgreSQL. We converted most of our well known fields over to proper PostgreSQL fields, and by using UUIDs in PostgreSQL we still had opaque sharable ids. On top of that, for developer flexibility, we included a little json dumping ground column in most of our tables. This allows developers to quickly add in some data they care about without dealing with migrations and database versioning. Then, as needed (and only if needed) we move the data out of json to proper columns, mostly for performance or relational reasons.