Event Sourcing Flow

Ironflow provides native event sourcing with entity streams, optimistic concurrency, schema evolution via upcasters, and projections that build read models. The write path appends events to a per-entity stream with version checking. The read path feeds the stream’s events to projections that materialize state. Upcasters run in the SDK when a function receives an event: they lift an old event to the current shape, and stored rows stay as written. The SDK projection runners do not run them.