How a 20-second app promo is actually built

Twenty seconds is long enough for five shots and short enough that every one of them has to earn its place. The structure below is not the only one that works, but it is the one that keeps working across categories, and it maps cleanly onto a mockup tool with a timeline.

The five beats

Zero to three seconds: the hook — the app on screen, doing its most recognisable thing, already in motion. Three to eight: the core action, shown large enough to follow. Eight to thirteen: a second capability, ideally on a different device to imply breadth. Thirteen to seventeen: the payoff — the result the user gets. Seventeen to twenty: identity — icon, name, one line, and where to get it. Cut on the beat; no crossfades, which read as softness and eat the moments either side.

Breathe between moves

The most common fault in home-made product videos is continuous camera motion. A move that arrives and then holds still for half a second lets the viewer actually read the screen; a camera that never stops means they never do. Aim for roughly a third of the total runtime to be held frames. If you measure your cut and find the camera is moving 95 percent of the time, you have a screensaver, not a promo.

Text on screen, not in the voiceover

Most viewers watch muted, so every essential idea needs to appear as a short caption. Give each caption its own window with a clean fade in and out, keep it to a few words, and never overlap two captions. Place them consistently — same position, same size — so the eye learns where to look and stops hunting.