Proa is a Rust-based web framework built for high performance, introducing a new composable, multi-target rendering model that can produce HTML, Markdown, and other targets from a single typed component.

Interactivity is additive to server-side rendering, using RSJS islands for client-side behavior with minimal JavaScript—about 1.3 KB gzipped per island—allowing small, targeted client code.

Adoption focuses on compatibility with existing stacks, supporting Axum-native routing and foreign-function interfaces from Node, Go, Python, and more, enabling incremental migrations by proxying routes to Proa.

Core architecture includes streaming SSR with document-order or out-of-order chunk flushing via Suspense, a Dataloader-backed WebContext for typed access to request-scoped data, and typed SSR semantics for layouts, routing, metadata, and assets.

Proa UI offers a Shadcn-like design system, with components typed in Rust and themeable through code, aiming to reduce JavaScript while preserving interactivity where needed.

The project demonstrates real-world recreations of apps like GitHub, Sentry, and Airbnb, accompanied by benchmarks that show Proa render speeds outperforming React’s renderToString in production scenarios.

Multi-target rendering is a core emphasis, with examples showing ProductCard rendering to Markdown and HTML, and a focus on fast server rendering with selective interactivity.