I was working on something similar, but for JVM backends [1]. And it seems there are a lot to learn from your project. For example, I'm using GraalVM that executes JS on the server. But I have to compile JS to WebAssembly because otherwise it produces a lot integration issues on the backend. Do you do the same?
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.
If anybody is wondering.
I don't really understand how it works, what part is Rust powered, is it reimplementing the JS engine in Rust?
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.
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.
it would be interesting to see a performance comparison to node and bun
"rust-powered" meaning it uses rolldown to bundle the javascript, that's fine, but it's a weird thing to highlight, it's confusing for people that aren't super familiar with vite and might think this is a rust framework
from the docs "one of rari's superpowers is seamless NPM package integration" this makes me think the docs are LLM-written... npm package integration, like every other javascript library.
now, the good: there's very few simple frameworks for react (react router and tanstack) and I think the simplicity here on going from an empty project to RSCs is absolutely great, and should be the tagline
I was also happily surprised at how mature the codebase is in comparison to the docs, the vite plugin actually supports a lot of the options I would have expected to see, they're just not documented yet
edit: I realised after digging a bit deeper this actually does have a rust runtime that runs the js, that was not very clear... is this separate from the framework or does the framework only run in the rust runtime? eg can it run on node?
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.
1/ an alternative framework for RSCs similar to nextjs, tanstack or react router
2/ a rust runtime for javascript, similar to node, deno or bun (except maybe not as general purpose)
Native speed with Rust compilation for blazing-fast builds and runtime"
It seems only Rust itself compiles slow while helping others brag about it :).
xlmnxp•1h ago