Software Engineering

Optimizing React Performance: Beginner’s Guide

As React apps grow, you may notice performance starting to lag – sluggish interactions, choppy animations, janky scrolling.

Luckily, there are many great techniques to optimize React app performance. Let’s look at some top tips:

Use React.memo for Component Memoization

The React.memo API can memoize component outputs:

const MyComponent = React.memo(function MyComponent(props) {
  /* only rerenders if props change */

This prevents unnecessary re-renders if props stay the same.

Virtualize Long Lists

Rendering thousands of rows kills performance. Virtualize rendering instead:

import { FixedSizeList } from 'react-window';

function List({ data }) {
  return (
      {({ index, style }) => (
        <div style={style}>

Only items visible on-screen are rendered.

Avoid Reconciliation with Keys

Keys help React distinguish elements from previous renders:

{ => (

Mismatching keys lead to full reconciliation.

Split Code with React.lazy

React.lazy allows code splitting components into separate bundles:

const OtherComponent = React.lazy(() => import('./OtherComponent'));

function MyComponent() {
  return (
    <React.Suspense fallback={<Loader />}>
      <OtherComponent />

Lazy loading avoids loading unnecessary code until needed.

Use useCallback Hooks

Wrap event handlers in useCallback to avoid regenerating functions:

const handleClick = useCallback(() => {
  // handler logic
}, []);

Avoids re-renders from new event handlers on each call.


  • Memoize components with React.memo
  • Virtualize long lists
  • Ensure keys are stable
  • Code split with React.lazy
  • Use useCallback hook

With some optimization, React can render complex UIs faster than ever.