Why Optimistic updates pattern in NextJS? - Purpose & Use Cases

The Big Idea

What if your app could feel instant, even when the network is slow?

The Scenario

Imagine you click a button to like a post, but you have to wait for the server to confirm before you see the like count change.

This delay makes the app feel slow and unresponsive.

The Problem

Waiting for the server response before updating the UI causes a lag that frustrates users.

If the server is slow or the network is bad, users might think the app is broken.

The Solution

The optimistic updates pattern immediately shows the new like count when you click, assuming success.

This makes the app feel fast and smooth, improving user experience.

Before vs After

✗ Before

await fetch('/api/like'); updateUI();

✓ After

updateUI(); await fetch('/api/like').catch(() => revertUI());

What It Enables

This pattern enables apps to feel instant and responsive, even when waiting for slow network calls.

Real Life Example

When you tap 'send' on a chat message, it appears immediately in the conversation before the server confirms it was received.

Key Takeaways

Manual updates wait for server response, causing delays.

Optimistic updates show changes instantly, improving speed.

They handle errors by reverting if needed, keeping data correct.