Spent the morning rewriting form validation. Inline errors are doing a lot of heavy lifting here.
Optimistic UI
A pattern where the UI shows the result of an action immediately, before the server has confirmed it.
When the user clicks 'like' or 'send', the UI updates as if it succeeded. If the server later returns an error, the UI rolls back and surfaces the failure. The benefit is perceived speed — the app feels instant — at the cost of having to handle reconciliation. Common in messaging, social feeds, and collaborative editing.
Also called
optimistic updateoptimistic rendering
When to use
- Frequent, low-stakes actions where most calls succeed (likes, reactions, toggles)
- Collaborative editing where waiting for the server kills the writing flow
- Mobile networks where latency is unpredictable
When not to use
- Actions where rollback would confuse the user (payments, irreversible operations)
- Critical state where eventual consistency would be misleading
Related
Source
Programming vernacular; popularized in modern JavaScript frameworks (React, Vue, Apollo, Linear).