React App Performance Checklist 2025

With Concurrent Rendering, React splits up complex UI work into smaller chunks, independently scheduling and executing each piece. This improves responsiveness during computation-heavy processes.

Automatic Batching combines several state update calls into one re-render, lessening the number of component updates and improving rendering efficiency.

<Suspense> and use Transition() provide loading states and deferred updates for more granular control over dynamic updates, improving user experience while fetching data or updating UI elements.

Prevent functional component re-renders due to unchanged props using   React. Memo.

Preventing re-creation of handlers on every render, especially in deeply nested child components, can be fixed with use Callback.

Expensive calculations or large data transformations that are not time sensitive can be cached using useMemo.

Avoid re-rendering the entire list for unchanged items by ensuring that list keys are unique and stable.

For non-essential components, utilize React.lazy() along with so that they won't load until they are needed. This can enhance the initial load time of the app.

For large libraries or parts rarely accessed, such as charts, maps, or modals, you can implement dynamic imports.

For route level splitting, utilize libraries like Next.js or React Router, to load only the necessary JavaScript with the current route.

Make sure to convert and serve images in newer formats like WebP or AVIF, which have better compression and no loss of quality.

For responsive images, use the srcSet attribute to provide multiple image sizes to serve based on their screen resolution and viewport.

To avoid pre-loading an image that is off-screen, use lazy loading with the loading="lazy" attribute on images.

Optimize your SVGs, and only use icon libraries or custom fonts when necessary to keep your page small.

Avoid adding every state-changeable piece of data to global state such as mouse position and/or form inputs. You want to keep that data as local as possible to keep the re-renders to a minimum.

For a larger scale app, consider utilizing more modern state libraries like Zustand, Jotai, or Recoil since they provide a better performance than the traditional Context API.

For asynchronous data, use libraries that provide baked-in functions to support features like caching, deduplication, background updates and pagination (like React Query or SWR).

If you frequently access API functions like live search, scroll events, or speedy input changes, debounce or throttle them so that you don’t needlessly update or request from the API.

Use libraries like react-window or react-virtualized. These libraries will help render only the potential visible part of your list, thus decreasing the amount of DOM nodes and improving the speed of rendering.

For APIs that return a sizable dataset (such as huge lists or tables), consider implementing pagination or infinite scroll so that you will only load in manageable pieces, or chunks, of data.

Include proper scroll-based loaders, skeletons, or any other type of scroll-based data loading indicator, so that the user experience remains smooth.

Build for production with npm run build, which minifies and optimizes the code.

Utilize either Webpack Bundle Analyzer or Source Map Explorer to identify large or unnecessary modules that contributed to the overall bundle size.

Use Chrome DevTools, React Profiler and Lighthouse to find render bottlenecks and accessibility issues.

Setup real-user performance monitoring with Sentry, LogRocket or Datadog to obtain performance metrics, errors and session replays.

Use hosting services like Vercel or Cloudflare to enable edge caching, automatic CDN adoption and instant rollbacks for modern web deployments.