How Reactra works

Reactra is a compiler. Understanding what it does at build time explains why the runtime is so small.

The pipeline

Your DSL source goes through a multi-pass pipeline: it’s preprocessed into valid TSX, parsed, the reactive graph is extracted, and finally React 19 code is emitted. The output uses only standard React APIs — React.use, useTransition, useSyncExternalStore — never useContext for the framework’s own wiring.

Fine-grained reactivity, no VDOM swap

Reactra doesn’t replace React’s rendering. It compiles your state/derived/store reads into precise subscriptions, so a component re-renders only when something it actually reads changes — including per-field store subscriptions.

The emission contract

The compiled file is ordinary React. That’s the whole point: your devtools, types, and debugger work on the output, and you can eject. The Why Reactra pages show the compiled output for real features.

Alpha

This concepts section is being expanded with the pass-by-pass pipeline, store scopes, and the observability model.