Config Schema and Runtime Unified in a Single Renderer

In a declarative UI platform, the renderer is both the authoritative definition of what the config schema means and the execution engine that brings it to life. Building (studio simulation) and running (end-user preview) go through the exact same code path.

The consequence is structural: schema and runtime behavior can never silently diverge. If a component type is invalid in simulation, it is invalid in production — by construction, not by discipline. Extending the system means registering a new component type once in the renderer; the builder and the runner both pick it up automatically, with no parallel update required.

This is the highest-leverage seam in a declarative system: keep the interpreter and the executor co-located, and correctness becomes a property of the architecture rather than a testing burden.

---

Source: data-app-factory PRD — renderer package design rationale See also: Declarative Data Apps, Reactive State Bus Pattern