We use event sourcing in a business application. Event sourcing, at it's core, is making sure your source of truth is a log of events and your app state is der

We use event sourcing in a business application. Event sourcing, at it's core, is making sure your source of truth is a log of events and your app state is derived from that. Beyond those constraints, there are many variations of how it can be done, each with very different tradeoffs.