Most React performance guides cover the basics: use memo, avoid unnecessary re-renders, lazy load routes. But what happens when your app grows to hundreds of components and millions of data points?
Profiling First
Before optimizing anything, profile. React DevTools Profiler and Chrome Performance tab are your best friends. We've seen teams spend weeks optimizing code that wasn't even in the hot path.
Virtualization
If you're rendering lists with more than 100 items, virtualize them. We use react-window for most cases and custom virtualization for complex layouts like our collaborative board.
State Architecture
The biggest performance killer in React apps isn't rendering — it's state management causing unnecessary re-renders across the component tree. Our rules:
- Keep state as local as possible — Don't put everything in global state
- Split contexts — One context per concern, not one mega-context
- Use selectors — With Zustand or Redux, select only what you need
Code Splitting
Beyond route-level splitting, we split at the feature level. Our marketing site loads the chatbot, video generator, and collaborative board only when the user scrolls to them.
Server Components & Streaming
For Next.js projects, we leverage React Server Components aggressively. Database queries, API calls, and data transformations happen on the server. The client receives ready-to-render HTML.
Measuring Success
We track Core Web Vitals religiously:
- LCP < 2.5s on all pages
- FID < 100ms for all interactions
- CLS < 0.1 to prevent layout shifts
Performance isn't a feature you add later. It's a constraint you design around from day one.