formsflow.ai uses MongoDB for form definition and form instances and Postgres for both BPM and WebAPI layers. The analytics component can connect to any database that Redash supports to create queries and visualizations. If the purpose is to migrate all data over to MS SQL, then the customer can create data pipelines to move over the data. To switch the backend database for BPM and WebAPI to MS SQL the customer would need to arrange some customizations on the code level.