Apache Superset
Apache Superset is an open-source platform for exploring data and building dashboards on top of SQL databases. It queries the source live and keeps no copy of the data itself.
It fits reporting on application data that has to stay inside the operator's infrastructure, where licence costs or vendor lock-in rule out commercial BI tools. We pair it with a read-only database connection and SQL views that flatten application structures into report-friendly tables. Dashboards can be embedded into an application with guest tokens and row-level security, or used directly in Superset.
Updates
For a multi-channel counselling platform of a non-profit foundation, we chose Superset to report on structured counselling records. It runs in production in containers on Kubernetes and reads the Drupal database through read-only SQL views. It is in production on one platform so far, so it sits in trial.