Lightweight, streaming-first React SSR framework built on Vite.
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Visit https://paretojs.tech/guides/introduction to get started with Pareto.
Pareto is a lightweight React SSR framework that prioritizes streaming. Built on Vite for instant dev starts, it provides file-based routing, NDJSON streaming for client navigation, per-route head management via React components, and Immer-powered state with automatic SSR hydration.
npx create-pareto my-app
cd my-app && npm install && npm run devPareto is built for throughput. In CI benchmarks against Next.js, React Router, and TanStack Start on identical hardware (Node 22, Ubuntu, 4 CPUs):
| Scenario | Pareto | Next.js | React Router | TanStack Start |
|---|---|---|---|---|
| Data Loading | 2,733/s | 293/s | 955/s | 1,386/s |
| Streaming SSR | 247/s | 236/s | 247/s | 247/s |
| API / JSON | 3,675/s | 2,212/s | 1,950/s | — |
| Static SSR | 2,224/s | 3,328/s | 997/s | 2,009/s |
Under ramp-up load (1→1000 concurrent connections), Pareto sustains the highest QPS before hitting the p99 < 500ms threshold:
| Scenario | Pareto | Next.js | React Router | TanStack Start |
|---|---|---|---|---|
| Data Loading | 2,735/s | 331/s | 1,044/s | 1,458/s |
| Streaming SSR | 2,022/s | 310/s | 807/s | 960/s |
| API / JSON | 3,556/s | 1,419/s | 1,912/s | — |
Client JS sent to the browser: 62 KB gzipped (vs Next.js 233 KB, React Router 100 KB, TanStack Start 101 KB).
In practice: a data-loading page serving 2,000 req/s at peak needs 1 Pareto server vs 6 Next.js instances. For streaming SSR, it's 1 vs 7.
Benchmark details: PR #12
- Streaming SSR —
renderToPipeableStreamwithdefer()for progressive data delivery through Suspense - Vite-powered — Instant dev starts, React Fast Refresh, native ESM in development
- File-based routing —
page.tsx·layout.tsx·loader.ts·head.tsx·document.tsx·not-found.tsx - Client navigation — SPA-feel
<Link>with prefetching, backed by NDJSON streaming - Head management — Per-route
head.tsxReact components with nested merge and deduplication - State management — Immer-powered
defineStore()anddefineContextStore()with automatic SSR hydration - TypeScript-first — Full type safety across loaders, pages, and configuration
- Security headers — Built-in OWASP baseline middleware
Visit paretojs.tech to view the full documentation.
@paretojs/core— Core frameworkcreate-pareto— Project scaffolding CLI
- GitHub Issues — Bug reports and feature requests
- GitHub Discussions — Questions and ideas
Contributions are welcome. Please open an issue first to discuss what you would like to change.
MIT
