Erudiax
React11 min read

React 19: What's New and Why It Matters

Discover React 19's new features and improvements. Learn about actions, automatic batching, better error handling, and how React 19 makes building apps easier and faster.

James Wilson
December 18, 2025
0.0k0

React 19 is here and it brings some exciting changes. If you're building React apps in 2025, you need to know what's new. Don't worry, I'll explain everything in simple terms.

What's New in React 19?

React 19 introduces server actions, automatic batching improvements, better error handling with error boundaries, and improved performance. The best part? It's backward compatible, so your existing code will still work.

Server Actions

Server actions let you call server functions directly from your React components. No more API routes for simple operations. Just write a function and call it - React handles everything.

Better Error Handling

React 19 makes error boundaries easier to use. Your app won't crash completely when something goes wrong. Plus, better error messages make debugging way easier.

Performance Improvements

Automatic batching works everywhere now, not just in event handlers. Your app will re-render less often and feel faster. These improvements happen automatically - no code changes needed.

Getting Started

I'll show you how to upgrade and start using React 19 features. Most of them work automatically, but some require small changes to unlock new capabilities.

#React#React 19#New Features#Modern React

Common Questions & Answers

Q1

What are the main new features in React 19?

A

React 19 introduces server actions for direct server function calls, improved automatic batching everywhere, better error boundaries, new hooks like useOptimistic, and performance improvements. It's backward compatible, so existing apps work without changes.

javascript
RunExplain
// Server Actions example
'use server';

export async function createTodo(title) {
  // This runs on the server
  await db.todos.create({ title });
  return { success: true };
}

// In your component
import { createTodo } from './actions';

function TodoForm() {
  async function handleSubmit(formData) {
    await createTodo(formData.get('title'));
  }
  
  return (
    <form action={handleSubmit}>
      <input name="title" />
      <button>Add Todo</button>
    </form>
  );
}
Q2

How do server actions work in React 19?

A

Server actions are functions marked with "use server" that run on the server. You can call them directly from client components, and React handles the network call automatically. No need to write API routes for simple server operations.

javascript
RunExplain
// Server action (server component or .js file)
'use server';

export async function updateUser(userId, data) {
  const user = await db.users.update({
    where: { id: userId },
    data: data
  });
  return user;
}

// Use in client component
'use client';
import { updateUser } from './actions';

function UserForm({ userId }) {
  async function handleUpdate(formData) {
    await updateUser(userId, {
      name: formData.get('name')
    });
  }
  
  return <form action={handleUpdate}>...</form>;
}

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