Isolated application environments take database-per-user architecture a step further by deploying a complete copy of the entire system for each customer. This approach is justified by data sovereignty requirements, customer-controlled upgrade pacing, or geographic latency needs — but not by bespoke customization, which fragments the product. Key design considerations include pushing complexity into provisioning and deployment rather than the application itself, maintaining a central control plane and catalog database, and enforcing strict software versioning discipline. Managing schema migrations across customers on different versions requires linearized upgrade paths and idempotent migration scripts to avoid conflicts. The tradeoff is significant operational overhead in exchange for per-customer flexibility.
