If you’ve built anything with React, Vue, or any modern frontend framework, you’ve probably come across the idea of optimistic UI updates. It sounds fancy. It sounds fast. It even feels good. Until it doesn’t.

Let me tell you why I almost never update state optimistically anymore, and why you might want to think twice before doing it too.

⚡ What Is an Optimistic Update?

Optimistic updates mean changing the UI before you know if the backend operation actually succeeded. For example, you click "like" on a post, and the heart icon turns red immediately, before the API call finishes.

setLiked(true) // optimistic update
await api.likePost(postId)

If something fails, you roll it back:

catch (error) {
  setLiked(false) // rollback
}

Seems harmless, right?

❌ Why I Stopped Using Optimistic Updates

1. Edge Cases Multiply Fast

Every time you write an optimistic update, you're creating an alternate reality. Now you have to write logic to reconcile the optimistic state with the real state if:

  • The request fails
  • The data changes from another tab or user
  • The user undoes the action before the request finishes
  • The server responds with something unexpected like validation or sanitization

That’s four edge cases for one button. Multiply that across a large app and your UI becomes a ticking time bomb.

2. Rollbacks Are a UX Nightmare

Users hate seeing the UI revert. Imagine typing a message, seeing it appear instantly, and then it disappears because the server threw a 500.

Yes, you can show toasts like “Action failed,” but most people don’t read those. It just feels like your app is broken or buggy.

3. It Breaks Consistency

Your UI state and your backend state go out of sync on purpose when you use optimistic updates. That’s dangerous.

Consistency between client and server is everything in multi-user apps. If you break that contract, you introduce bugs that are extremely hard to debug, especially when multiple users are involved.

4. You’re Not Facebook

Optimistic updates are mostly popularized by companies that can afford massive infra and logic to handle them properly.

You probably have:

  • A few devs, maybe just you
  • No conflict resolution backend
  • No retry queue
  • No live event stream syncing the UI

Without all of that, optimism is a luxury you can’t afford.

🧠 What I Do Instead: Pessimistic + Immediate Feedback

I do this:

setLoading(true)
await api.likePost(postId)
setLiked(true)
setLoading(false)

And optionally show a spinner or skeleton. Sure, it's 100 to 300 ms slower, but I:

  • Don’t need to roll anything back
  • Don’t need to guess what the server will return
  • Keep the UI and backend state always in sync
  • Avoid writing extra logic for "what if it fails"

Clean code. Predictable behavior. No surprise bugs at 3 am.

🔄 When I Do Use Optimistic Updates

Okay, I lied a little. I’ll use optimistic updates if and only if:

  • The failure state doesn't matter, like liking a post that no one else sees
  • The action is idempotent
  • I have background sync or retry logic
  • I’m willing to tolerate inconsistency

In most CRUD apps, not worth it.

💡 Final Thoughts

Optimistic updates are like gambling. Sometimes you win. But when you lose, the debugging cost is massive.

Instead of betting that your API won't fail, just build for the world we live in. A world where servers crash, networks flake, and users click faster than requests resolve.

You don’t need optimism. You need resilience.

✍️ What do you think? Do you use optimistic updates in your app? Have they bitten you before? Let’s talk in the comments.