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? That's not just annoying—it's breaking the trust between your user and your interface.
I learnt this the hard way while building an AI chat feature. Users would send a message, and there'd be this awkward pause before their message appeared in the chat. Even though the API was responding in 200 milliseconds, 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: the user does something, you show a spinner, wait for the server to confirm, then update the UI. It's safe. It's predictable. It's also what makes your app feel like it's running through molasses.
Think about it 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. Like, 99% of the time, that API call is going to return a success. So we're making users wait every single time for the 1% chance something goes wrong.
The Optimistic Approach
Here's the mindset shift: assume the action will succeed, update the UI immediately, and deal with failures if they happen.
When someone sends a message in a chat, show it in the chat right away. Make the API call in the background. If it fails (which it rarely does), you handle it gracefully. Maybe you show a little "failed to send" indicator. Maybe you let them retry. But you don't make them wait when everything is working fine.
I rebuilt that AI chat feature with this pattern. The message appears instantly when you hit send. The typing animation from the AI starts right away. Behind the scenes, the message is being saved to the database, but the user doesn't need to wait for that confirmation to feel like their action worked.
The difference was night and day. 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 building a simple todo list feature. You know the drill — user clicks delete on an item, you show a loading state, call the API, then remove the item from the list.
I switched it to optimistic updates. Click delete, item disappears immediately. API call happens quietly in the background. If it fails, the item reappears with a small toast notification saying "couldn't delete, try again."
What surprised me was how much faster the whole interaction felt, even though the actual API timing hadn't changed at all. The perceived performance went through the roof just by not making people wait to see the result of their own decision.
The Mistake Everyone Makes
Here's what I got wrong at first, and I see this in a lot of implementations: I forgot to actually handle the error case properly.
It's easy to write the happy path. Update the UI, fire the API call, done. But what happens when that call fails? If you don't store the previous state before making your optimistic update, you can't roll back. Your UI is now lying to the user, showing them something that didn't actually happen on the server.
The pattern needs three things to work. First, you store the current state before making any changes. Second, you update the UI optimistically. Third, if the API call fails, you restore that previous state and tell the user what happened.
Here's what that looks like in practice:
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 to do, UI already updated
})
.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—doesn't matter. The concept is the same. Update immediately, sync later, rollback on failure.
When Not to Use This
Now, before you go making every single action in your app optimistic, let's talk about when this is a bad idea.
Financial transactions? Don't be optimistic. You really do need to wait for confirmation before telling someone their payment went through. Deleting important data permanently? Maybe show a confirmation dialog first, then be optimistic about the actual deletion.
The rule I follow is this: if the action is easily reversible and failure is rare, be optimistic. If the action has serious consequences or you need guaranteed confirmation, wait for the server.
A like button? Perfect for optimistic updates. Processing a $10,000 wire transfer? Maybe not.
Why This Matters More Than You Think
Here's the thing about user experience that took me a while to understand. Users don't consciously notice when things are fast. They notice when things feel slow. That 300 millisecond wait for a server response? Your users might not be able to measure it, but they feel it.
Apps that use optimistic updates feel native. They feel responsive. They feel 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 they do give you that genius undo option in case you change your mind).
These apps 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. Would love to connect and hear about your own experiences with optimistic updates.