How to make a TikTok ad for your app with a reaction hook

The split-screen reaction ad is one of the most reliable formats for app install campaigns: a real person reacts on top, your app shows why below. It looks like a post, it explains itself on mute, and you can build one in about thirty minutes.

Here is the exact workflow.

What you need before you start

• A screen recording of the one moment in your app worth reacting to. Record at the native resolution of your phone, with notifications off.
• Two to five reaction clips, each two to four seconds long, vertical.
• An editor. CapCut, the TikTok editor or any tool that can stack two videos and add text.

Keep the screen recording short — ten to fifteen seconds. The reaction ad is not a product tour.

Step 1: Pick the moment worth reacting to

Before you look for a reaction, decide what it's a reaction to. Scroll through your app and find the moment that makes new users say "oh, nice". It's usually one of these:

• A result that appears instantly (a meal plan, a translated document, an edited photo)
• A number that surprises (money saved, hours slept, calories counted)
• Something that used to be annoying, now done in one tap

Write that moment down as a single sentence. This sentence becomes your caption later.

Step 2: Match the emotion to the moment

The reaction should fit what the viewer is about to see. A useful mapping:

Then match the setting. A study app reaction belongs at a desk; a fitness reaction belongs in a gym or at home in workout clothes.

this app does THAT?

it explained it better than my teacher

wait, it's that easy?

I'm never going back

Step 3: Build the split screen

1. Create a 1080×1920 project.
2. Put the reaction on the top half, scaled to fill. Center the face so it isn't cropped by the caption.
3. Put the screen recording on the bottom half. Crop away status bars if they distract.
4. Start the screen recording roughly half a second after the reaction begins, so the viewer sees the reaction first.

If you'd rather go full screen, run the reaction for two to three seconds, then cut hard to the app. Split screen tends to work better when the payoff is visual and instant; full screen works better when the app needs room.

Step 4: Write one line of text

The caption carries the hook for everyone watching on mute. Write it like a person, not a brand:

• "wait… this app does THAT?"
• "why did nobody tell me about this"
• "I didn't believe it until I tried it"

Place it in the top third, inside the safe zone — TikTok's interface covers the bottom and right edges. Use the platform's native text style; a custom font is a quick tell that it's an ad.

Step 5: Add sound, carefully

Silence or a trending sound at low volume both work. Avoid stock music that sounds like an ad. If your reaction clip has natural audio — a gasp, a laugh — keep it; it helps the minority who watch with sound on.

Step 6: Export variants, not one ad

Here is where reaction ads become cheap to test. Keep the same screen recording and caption, and swap only the reaction. Three to five hooks on the same body tell you more than three completely different ads, because you're changing one variable.

Export each at 1080×1920. Name files by hook so results are easy to read later: mealplan_shocked-kitchen_v1.mp4.

Step 7: Read the results

Give each variant enough spend to get a few thousand impressions, then compare:

• Hook rate (3-second views ÷ impressions) tells you which reaction stops the scroll.
• Hold rate tells you whether the payoff keeps them.
• Cost per install is the final word.

A high hook rate with a weak hold rate means the reaction overpromised. A low hook rate with a good hold rate means the payoff is strong and the hook needs another try.

Keep the winners fresh

Even a great hook wears out once the same audience has seen it a few times. When your best ad's hook rate starts dropping, don't rebuild the whole thing — swap in a new reaction with a similar emotion and keep the body. For more angles to test, see our reaction hook ideas by app niche.

FAQ

How long should a reaction hook be?+

Two to four seconds. Long enough to show the emotion clearly, short enough that the app demo arrives before the viewer scrolls.

Do I need a video editor to make a reaction ad?+

No. CapCut or the TikTok editor is enough: stack the reaction on top, the screen recording below, add one caption and export at 1080×1920.

Should I add music or voiceover?+

Use a trending sound at low volume or none at all. The reaction and the caption should carry the hook on mute.