Make Your App Feel Instant with Optimistic Updates

Source: Dev.to

The Tiny Moment of Friction

You know that tiny moment of friction when you click “like” on a post and have to wait for the heart to fill in? That split second where you’re not sure if it worked? It’s not just annoying—it’s breaking the trust between your user and your interface.

I learned this the hard way while building an AI‑chat feature. Users would send a message, and there’d be an awkward pause before their message appeared in the chat. Even though the API responded in ~200 ms, it felt sluggish. People would click Send again, thinking it didn’t work. The feature was fast, but it didn’t feel fast.

That’s when I discovered optimistic updates, and honestly, it changed how I think about building interfaces.

What Actually Happens When You Wait

Most apps work like this:

1. User does something.
2. Show a spinner.
3. Wait for the server to confirm.
4. Update the UI.

It’s safe and predictable, but it also makes your app feel like it’s running through molasses.

From the user’s perspective, they just told your app to do something. They clicked the button. They made the decision. Why should they wait for permission from a server somewhere to see the result of their own action?

The thing is, most actions succeed. ~99 % of the time the API call returns success, so we’re making users wait for the 1 % chance something goes wrong.

The Optimistic Approach

Mindset shift: assume the action will succeed, update the UI immediately, and handle failures if they happen.

• When someone sends a message in a chat, show it right away.
• Make the API call in the background.
• If it fails (rare), show a small “failed to send” indicator and let the user retry.

I rebuilt that AI‑chat feature with this pattern. The message appears instantly when you hit Send; the AI’s typing animation starts right away. Behind the scenes the message is saved to the database, but the user doesn’t need to wait for that confirmation to feel like their action worked.

Result: Night‑and‑day difference. People stopped double‑clicking Send. The feature felt responsive and alive instead of sluggish and disconnected.

The Delete Story

Another place this really hit home was a simple todo list feature. The usual flow:

1. Click Delete.
2. Show a loading state.
3. Call the API.
4. Remove the item from the list.

I switched it to optimistic updates:

• Click Delete → item disappears immediately.
• API call runs quietly in the background.
• If it fails, the item reappears with a toast: “Couldn’t delete, try again.”

Even though the actual API timing didn’t change, the perceived performance skyrocketed. Users felt the interaction was fast.

The Mistake Everyone Makes

What I got wrong at first (and see a lot of implementations do) is not handling the error case properly.

It’s easy to write the happy path:

// optimistic update, fire API, done

But if the call fails and you haven’t stored the previous state, you can’t roll back. Your UI is now lying to the user.

The pattern needs three things:

1. Store the current state before making any changes.
2. Update the UI optimistically.
3. If the API call fails, restore the previous state and inform the user.

Example (delete item)

function deleteItem(itemId) {
  // Step 1: Store what we have now
  const previousItems = [...items];

  // Step 2: Update UI immediately (optimistic)
  items = items.filter(item => item.id !== itemId);

  // Step 3: Sync with server
  api.deleteItem(itemId)
    .then(() => {
      // Success! Nothing else to do
    })
    .catch(() => {
      // Failure! Restore previous state
      items = previousItems;
      showToast('Failed to delete item. Please try again.');
    });
}

The beautiful thing about this pattern is that it works in any framework—React, Vue, Angular, Svelte—because the concept is the same: update immediately, sync later, rollback on failure.

When Not to Use This

Before you go making every single action optimistic, consider when it’s a bad idea.

Rule of thumb: If the action is easily reversible and failure is rare, be optimistic. If the action has serious consequences or requires guaranteed confirmation, wait for the server.

Why This Matters More Than You Think

Users don’t consciously notice when things are fast; they notice when things feel slow. That 300 ms wait for a server response? Users might not be able to measure it, but they feel it.

Apps that use optimistic updates feel native, responsive, and like the interface is actually listening to you instead of asking permission from a server every time you breathe.

• Instagram doesn’t make you wait to see your like.
• Twitter doesn’t make you wait to see your retweet.
• Gmail doesn’t make you wait when you archive an email (but it gives you an “undo” option just in case).

These apps understand that perceived performance is as important—if not more—than raw latency. By embracing optimistic updates where appropriate, you can make your app feel instantly alive.

Users feel fast because they trust that your actions will succeed and deal with failures as the exception, not the rule.

The Implementation Reality

When I first started using this pattern, I thought I’d need to rewrite huge chunks of my apps. Turns out, you can adopt it incrementally. Pick one feature that feels slow. Add optimistic updates to just that feature. See how it feels.

Start with something low‑stakes like a like button or a simple toggle. Get comfortable with the pattern of store → update → sync → rollback. Once you’ve done it a few times, it becomes second nature.

The code isn’t complicated. The mindset shift is what matters. You’re moving from “ask permission, then act” to “act, then sync.”

Wrapping Up

Optimistic updates aren’t some advanced technique reserved for big‑tech companies with massive engineering teams. It’s a simple pattern that makes a massive difference in how your app feels to use.

The next time you’re building a feature and you catch yourself adding a loading spinner, ask yourself: does the user really need to wait for this? Can I show them the result immediately and sync in the background?

More often than not, the answer is yes. And your users will thank you for it, even if they don’t consciously realize why your app just feels better to use.

If you found this helpful, I share more practical frontend tips and real experiences from building with modern frameworks over on LinkedIn. I’d love to connect and hear about your own experiences with optimistic updates.