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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.
That said, rari takes a different approach. It's not a pure Rust framework. It's a React Server Components framework that happens to be powered by a Rust runtime. The goal is to abstract away Rust's complexity entirely so JavaScript/TypeScript developers can build high-performance React apps without needing to learn Rust.
The inspiration was pretty straightforward: I wanted to build something for myself that was as performant as I could make it. I'd been using Rust a lot more in my day-to-day work and wanted to see if I could bring those performance benefits to React development without forcing JS devs to write Rust. The goal was to abstract away the complexity of Rust but still deliver the same benefits.
Congrats on shipping your project! What did you build?
The runtime piece is definitely less general-purpose than Node/Deno/Bun. It's optimized specifically for React Server Components with things like streaming, Suspense boundary handling, and server action execution baked in. You wouldn't use it to run arbitrary JS apps.
The key is that deno_core provides clean Rust bindings to V8's C++ API, which lets us run JS/TypeScript with minimal overhead. We handle module resolution, imports, and the React rendering pipeline all in Rust, then execute the actual component code in V8. No WASM compilation step needed.
Your JVM project looks cool! The GraalVM → WASM approach makes sense for JVM integration. We avoid those integration issues by keeping everything in the Rust/V8 ecosystem. The tradeoff is we're tied to V8, but we get native performance and direct access to V8's features.
While we use Deno's excellent crates (deno_core for V8 bindings, we're big fans of the project!), you're not locked into the Deno ecosystem. rari uses standard node_modules resolution, so your existing Node/npm workflows just work. Think of it like this: Deno gives you a runtime to build on, while rari gives you the full stack with integrated bundler, router, HMR, and dev server all configured to work together for RSC apps.
On the npm integration point: what I should have said is that rari's Rust runtime handles traditional node_modules resolution (require/import from node_modules), which is actually pretty rare for Rust-based JS runtimes. Deno, for example, uses npm specifiers instead of node_modules.
Great feedback on the tagline too. "Zero to RSC in minutes" is way clearer than what we have now. The codebase is definitely ahead of the docs, I've been focused on getting the runtime solid first, but clearly need to catch the documentation up.
Thanks for taking the time to dig in and give constructive feedback. This is exactly the kind of input that helps make it better.
The Rust part is the server runtime. Instead of Node.js running your React Server Components, rari uses a Rust server with an embedded V8 engine. Same React code, different server underneath.
You write React → Rust server executes it → better performance than Node-based alternatives.
- 0.69ms avg response (3.8x faster than Next.js) - 20,226 req/sec throughput (10.5x higher) - 4ms P99 latency under load (12x faster) - 68% smaller bundles (27.6 KB vs 85.9 KB)
The key insight: when your architecture aligns with React's design philosophy, performance follows naturally. Server components by default, 'use client' when needed, true SSR from the Rust runtime.
GitHub: https://github.com/rari-build/rari Benchmarks: https://github.com/rari-build/benchmarks Try it: `npm create rari-app@latest`
Happy to answer questions about the architecture and how we achieved these numbers.
Key results vs Next.js: - 4.04x faster component rendering under load - 3.74x higher throughput (10,586 vs 2,832 req/sec) - 5.8x faster build times - 100% React Server Component compatibility
Built on a custom Rust runtime with V8, and intelligent Vite integration. All benchmarks are reproducible.
Try it: https://rari.build Code: https://github.com/rari-build/rari Benchmarks: https://github.com/rari-build/benchmarks