The Firebase Realtime Database is a cloud-hosted NoSQL database that lets you store and sync data between your users in realtime.
Tableau reads flat files directly from Google Sheets, Google Cloud Storage or Google Drive.
Flatly is a cloud-based Software as a Service (SaaS) that replicates business data as flat files (CSV, XLSX, or Sheets) in cloud storage. The service can be configured through a set of "jobs" or "job settings" which control the replication and syncing of data. Once a job is set to run, Flatly runs as an invisible background service.