Domain-driven, event-sourced, a modular monolith built around features, configured per tenant. Years of production experience married to current tooling.
One solid core and the ring of configuration around it.
Events are the system of record; state is derived. Commands in, queries out.
Every property is a date series. Where a greenfield design oversimplifies.
What is configuration and what is code.
One deployment, many tenants, isolated by design.
Every aggregate, its verbs and its events, generated from the code.