React 19 Best Practices: Write Clean, Modern, and Efficient React Code

React 19 brings automatic memoization, async-safe context, Actions for forms, stable server components, and smarter asset loading. To fully leverage these features, it’s important to follow modern best practices. This guide walks through tips, patterns, and strategies to write clean, maintainable, and high-performance React 19 apps.

1. Embrace Automatic Memoization

React 19’s React Compiler automatically memoizes components, reducing unnecessary re-renders.

Best Practices:

• Remove redundant React.memo, useMemo, and useCallback where not needed
• Keep components small and focused to maximize compiler optimizations

// Small, focused component function UserCard({ user }) { return <p>{user.name}</p>; } 

Tip: Measure performance with React Profiler to see where manual memoization may still be needed.

2. Use Async-Safe Context

With the new use() hook, React 19 allows context to be used safely in async boundaries.

Best Practices:

• Use context only for global/shared state (theme, auth, language)
• Avoid storing frequently changing data in context — prefer local state for dynamic updates

const ThemeContext = createContext("light"); function App() { const theme = use(ThemeContext); // async-safe return <div className={theme}>...</div>; } 

3. Leverage Actions for Forms

React 19 Actions make forms simpler and server-friendly.

Best Practices:

• Use Actions for server-side mutations whenever possible
• Keep client logic minimal in forms
• Combine Actions with server components for clean architecture

async function postComment(formData) { "use server"; await db.comments.create(formData); } <form action={postComment}> <input name="text" /> <button type="submit">Post</button> </form> 

4. Use Server Components Wisely

Server Components reduce bundle size and improve initial render speed.

Best Practices:

• Move non-interactive components (lists, tables, content) to the server
• Keep interactive components (buttons, forms) as client components
• Combine with Suspense for smooth loading states

// Server Component export default async function ProductList() { const products = await db.products.getAll(); return products.map(p => <p key={p.id}>{p.name}</p>); } 

5. Optimize Asset Loading

React 19 handles asset loading more efficiently.

Best Practices:

• Remove unnecessary <link> preloads if React handles them automatically
• Monitor Web Vitals and Lighthouse scores after upgrading
• Lazy-load large components with React.lazy + Suspense

const Chart = React.lazy(() => import("./Chart")); <Suspense fallback={<p>Loading chart...</p>}> <Chart /> </Suspense> 

6. Use Concurrent Rendering Features Thoughtfully

Concurrent rendering improves UX but requires careful usage.

Best Practices:

• Use startTransition for non-urgent state updates
• Use Suspense to suspend UI during data fetching
• Avoid blocking main UI updates with heavy computations

import { startTransition } from "react"; startTransition(() => { setSearchResults(filteredData); }); 

7. Keep State Local Whenever Possible

Lifting state too high triggers unnecessary re-renders.

Best Practices:

• Store state in the nearest component that needs it
• Use context for truly shared state
• Consider custom hooks for reusable logic

function useToggle(initial = false) { const [state, setState] = useState(initial); const toggle = () => setState(prev => !prev); return [state, toggle]; } 

8. Testing and Debugging

React 19 introduces async-safe features that may break poorly tested apps.

Best Practices:

• Test server components with proper mocks
• Use React Profiler to identify re-renders
• Verify Suspense boundaries for smooth UX

Final Thoughts

React 19 is about less boilerplate, better performance, and modern DX. By following these best practices, you can:
Write cleaner code
Reduce bugs and unnecessary re-renders
Improve performance for users
Fully leverage server components and new features

React 19 makes modern React development faster and easier, but only if you adopt best practices early.

What best practices are you using in React 19? Share your tips in the comments — let’s help the community write better React apps!