React powers over 40% of the top 10k sites, but most hit perf walls past 5k concurrent users. Client-side rendering tanks TTI above 2s, and bundle bloat kills mobile.
On a recent IRPR project for a New York fintech, we rebuilt their dashboard in React. Went from 500ms latency to 150ms, handling 25k req/s on Vercel.
You need expert patterns: Server Components, optimized queries, and zero-config deploys. Here's what we ship in production.
- Framework: Next.js 15 App Router + React 18.3. Server Components first.
- Data Fetch: TanStack Query v5. Cached fetches, optimistic updates.
- State: Zustand v5 client-side. Server Actions for mutations.
- Styling: Tailwind v3.4 + shadcn/ui. 20kb CSS after purge.
- ORM/DB: Drizzle ORM + PostgreSQL 16. Type-safe queries.
8-Week React MVP Timeline
Weeks 1-2: Foundations
Set up Next.js 15 monorepo with Turborepo. Scaffold auth via Lucia + PostgreSQL. Write Server Components for core pages. Bundle size under 100kb gzipped.
Weeks 3-4: Data Layer
Integrate TanStack Query. Migrate fetches to RSC. Add Drizzle schemas, run migrations. Test 500 req/s locally with Artillery.
Weeks 5-6: Features + Opts
Build dynamic UIs with Suspense boundaries. Lazy load routes. Profile with React DevTools Flamegraph. Hit 100ms LCP.
Weeks 7-8: Deploy + Monitor
Vercel preview deploys. Sentry for errors, Prometheus for metrics. Load test to 10k users. Ship.
Perf Optimization Steps
- 1
1. Audit Current Bundle
Run `next build` and check analyzer.vercel.build. Target under 200kb gzipped total. Remove lodash, use native Array methods.
- `npm i @next/bundle-analyzer`
- Prioritize code splitting with dynamic imports.
- 2
2. Go Server-First
Convert components to Server Components. Fetch data in RSC, pass props down. Cuts client JS 70%. Example: ```tsx const Page = async () => { const data = await db.query('SELECT * FROM users'); return <ClientList data={data} />; }; ```
- Use `cache: 'force-cache'` for static data.
- 3
3. Query Caching
Wrap fetches in TanStack Query. Set staleTime: 5 * 60 * 1000. Prefetch on hover. Dropped re-renders 80%.
- `useQuery({ queryKey: ['users'], queryFn: fetchUsers })`
- Devtools: tanstack.com/query/latest
- 4
4. Edge Deploy
Deploy to Vercel Edge. Serverless functions at 50ms cold start. Chicago client saw 90th percentile p95 at 120ms.
Advanced React Tips
1. Custom Hooks for Reuse
Build usePaginatedQuery with infinite queries. Reuse across tables. Saved 2 weeks dev time on LA project.
- Handle errors globally with QueryClientProvider.
2. Memoize Aggressively
`useMemo` for computed values, `useCallback` for handlers. Pair with React.memo. 40% less re-renders.
- Avoid inline functions in JSX.
3. Suspense Waterfalls
Parallel fetches in RSC. No waterfalls post-React 18. Bundle hydration down to 200ms.
4. Zod Validation Everywhere
Schema on every API response. TypeScript infers from Zod. Zero runtime type errors.
Pitfalls We Fixed
Overusing useEffect
useEffect chains cause waterfalls. Switch to Query or SWR. Fixed 300ms load time.
Client-Only State Explosion
Redux for everything bloats. Use URL params + Server Actions. Zustand slices per feature.
No Hydration Checks
SSR mismatch crashes. Use useEffect for client-only mounts. `if (typeof window === 'undefined') return null`.
Ignoring Core Vitals
LCP >2.5s kills SEO. Optimize images with Next Image. Aim CLS <0.1.
The IRPR engineering team ships production software for 50+ countries. Idea → Roadmap → Product → Release. 200+ products live.
About IRPR