rari is a React Server Components framework with a Rust-powered runtime. It's not a compiler that converts React to vanilla JavaScript—it's a full framework (like Next.js) that runs React applications.

The Rust part is the runtime engine that executes your React code on the server. Think of it as a faster alternative to Node.js for running React Server Components. You still write normal React code, but the server-side execution happens in Rust instead of Node.js, which gives it massive performance gains (46.5x higher throughput than Next.js).

It handles routing, server-side rendering, and serves both server components (rendered on the server) and client components (interactive JavaScript sent to the browser). The output is still HTML + JavaScript that runs in the browser—just generated much faster.