the proof of the pudding (is in the eating)

idiomPart ofpudding

the proof of the pudding (is in the eating) — idiom

1. You can only judge whether something is good or effective by trying it or puttin

1.idiom
Definition

You can only judge whether something is good or effective by trying it or putting it to use, not by how it looks or sounds in theory.

Example

Critics praised the new app's design, but the proof of the pudding is in how users actually interact with it.

The team's strategy looks good on paper, but the proof of the pudding will come when we see the sales figures next quarter.