Smooth, Smarter UIs: Exploring React Labs’ View Transitions and Activity

The React team is back at it again — pushing the boundaries of frontend development with experimental features designed to make UI interactions smoother, smarter, and more delightful.

In their April 23, 2025 blog post, the React core team unveiled two exciting innovations from React Labs:

• View Transitions: Seamless, declarative UI animations powered by native browser APIs.

• Activity: A smart way to hide/show components without unmounting them.

In this blog, we’ll break these down in simple terms, show you real-world examples, and explore what they mean for the future of building React applications.

Let’s dive deep.

Why These New Features Matter

Before jumping into the technicals, let's understand the "why."

• Animations today are hard. They often require complex state management or third-party libraries.

• Stateful UIs suffer performance hits. Toggling visibility usually leads to full unmounts, forcing components to lose state and re-render unnecessarily.

The new View Transitions and Activity APIs are React's solution to these problems — they make fluid, performant UIs a natural part of your app, not an afterthought.

What is View Transitions in React?

View Transitions bring built-in animations to React components during UI changes like navigation, state updates, or data fetching.

Think of it like a magic lens that smooths over the jarring, jumpy feeling you sometimes get when content updates on the page.

How it Works

View Transitions tap into the browser’s startViewTransition() API, but wrapped in React's declarative model.

In short:

• What to animate: Wrap parts of your UI inside <ViewTransition>.

• When to animate: Use React transitions (startTransition, useDeferredValue, or Suspense) to trigger animations.

• How to animate: Style transitions using special CSS view transition pseudo-selectors.

Basic Example

>_ Jsx
1import { ViewTransition } from 'react';
2
3export default function Profile({ user }) {
4  return (
5    <ViewTransition>
6      <div className="user-card">
7        <h2>{user.name}</h2>
8        <p>{user.bio}</p>
9      </div>
10    </ViewTransition>
11  );
12}

When this component’s props change (like a different user), the old and new UI smoothly animate instead of instantly snapping.

Styling the Animation

>_ Css
1::view-transition-old(*) {
2  animation: fade-out 300ms ease-out;
3}
4
5::view-transition-new(*) {
6  animation: fade-in 300ms ease-in;
7}
8
9@keyframes fade-out {
10  from { opacity: 1; }
11  to { opacity: 0; }
12}
13
14@keyframes fade-in {
15  from { opacity: 0; }
16  to { opacity: 1; }
17}

Boom — just like that, your user card updates with a polished fade instead of a hard switch.

Shared Element Transitions

It gets even cooler: you can name a <ViewTransition> to link elements between renders.

Imagine clicking a product thumbnail and having it smoothly expand into a detailed view — without the product feeling like it "jumps" across the screen.

>_ Jsx
1<ViewTransition name="profile-photo">
2  <img src={user.photoUrl} alt="Profile Photo" />
3</ViewTransition>

The shared name makes the browser understand that this element in the old UI and the new UI are the same thing — just changing shape, position, or size.

What is Activity in React?

The Activity API solves a different, but equally important problem:

"How do I hide parts of my UI without destroying and re-creating them?"

In today's React, if you unmount a component, you lose:

• Internal state (e.g., scroll position, input values, timers)

• DOM setup (e.g., media loading, event listeners)

Activity introduces a new pattern: hiding components without unmounting them.

Basic Example

>_ Jsx
1import { Activity } from 'react';
2
3export default function Dashboard({ page }) {
4  return (
5    <>
6      <Activity mode={page === 'home' ? 'visible' : 'hidden'}>
7        <HomePage />
8      </Activity>
9      <Activity mode={page === 'settings' ? 'visible' : 'hidden'}>
10        <SettingsPage />
11      </Activity>
12    </>
13  );
14}

When switching between HomePage and SettingsPage:

• Hidden components are visually gone but remain mounted.

• Visible components appear instantly, keeping their internal state.

Why This Matters

• Better performance: No teardown or reconstruction of hidden components.

• Smooth user experience: Instant switching without loading spinners.

• Simpler code: No need for manual caching hacks or invisible div tricks.

Real-World Use Cases

Both View Transitions and Activity unlock powerful new UX patterns:

• View Transitions Smooth page navigation, content sorting, gallery preview animations, shared element transitions (like photo expanders).

• Activity Tabbed interfaces, multi-step forms, modal managers, persistent background tasks.

Important Notes

• These features are experimental. They are available under react@experimental and not yet part of stable React.

• Browser support for startViewTransition() is expanding but may not be universal yet.

• Using these APIs responsibly will future-proof your app for when they graduate into stable React.

The Future of React UIs Looks Smooth and Smart

React's vision has always been about making complex UI problems feel simple and intuitive.

With View Transitions and Activity, the framework is pushing toward zero-friction, delightful user experiences — all while staying true to React’s declarative philosophy.

These new APIs don't just add bling to your apps — they fundamentally make user experiences better: more responsive, more engaging, and more human.

If you're building ambitious UIs, start experimenting today. Future React will likely make these features mainstream — and mastering them early could give your projects a serious edge.