On the Difference Between Fast and Snappy

Speed and snappiness are not the same thing. Speed is the actual time it takes for a system to respond. Snappiness is whether the user perceives that response as instant. The two diverge more often than designers acknowledge.

The classic example: a 50-millisecond network request that updates the UI 50 milliseconds after the user clicks. By any technical measure, this is fast. To the user, it feels slightly delayed, because the UI is reacting to the network response instead of the input.

The snappy version: the UI responds immediately to the input — optimistic update — and the network request happens in the background. The actual response time may be longer, but the perceived time is zero. This is the entire trick behind every interface that "feels fast."

The Principles

Acknowledge every input within 100 milliseconds. The acknowledgment can be visual (button-press state, ripple, color change). It does not have to be the result of the action. It just has to confirm that the input was received.

For actions that take longer than 300 milliseconds, show a loading state. For actions that take longer than 3 seconds, show progress.

For actions that can be optimistic (likes, follows, bookmarks, draft saves), do them optimistically. Roll back on failure.

Most "slow" interfaces are not slow. They are silent. The user is waiting because they do not know if the system heard them.