Event sourcing at Orus
Event sourcing is rarely used as the foundation of the whole system, but at Orus, we had the chance to start from scratch, and think things through before writing the first line of code.
Insurance is complicated, and we need to know exactly what happened at any given time.
When a claim is filed, a contract renewed, or a coverage added, the "current state" of a database row isn't enough. We need to answer: Who changed this? When? Why? And what did the contract look like exactly before that change?
In a standard CRUD application, you might add an audit log table. But audit logs rot. They get out of sync with the actual data. In event sourcing, the audit log is the data.
We decided early on to build our backend (TypeScript/Node.js) on a 100% event sourced architecture. It wasn’t the easiest path, but it was the right one for our domain.