Multitenancy may seem straightforward until real-world users and compliance show up. Which approach to multitenancy should we choose, and why is one better than another? In this talk, we will review two production cases (you may even be a user of these apps): schema-per-tenant in a relational database (PostgreSQL) and database-per-tenant in a document database (MongoDB). We also cover app-per-tenant and row-level separation, outlining the trade-offs in terms of isolation, cost, and operational complexity, as well as practical patterns for provisioning, routing, and migrations in Java.

JEurope 2026