Type 1: overlay apps (react to a video)
An overlay video reaction app plays a clip on screen and records your face in a corner while you watch. It is the classic YouTube and TikTok format. Editors such as CapCut and iMovie can do this with picture-in-picture, and TikTok's Duet and Stitch features are built for it.
Good for: reacting to trailers, music videos and other creators' clips.
Not good for: anything that happens in the real world.
Type 2: live dual camera apps (react to a moment)
A live reaction video app records the iPhone's front and back cameras at the same time, so one camera catches the moment and the other catches the reaction. There is no clip to import: it is happening in front of you.
Good for: surprises, gifts, results day, sport, kids and pets.
Not good for: reacting to a file already on your phone.
Lookout is this kind of app. It is free, works on any iPhone XS or newer, and keeps the video on your phone.
Comparison
| Overlay apps | Live dual camera apps | |
|---|---|---|
| What you react to | A video on your phone | Something happening now |
| Cameras used | Front only | Front and back together |
| Can redo the moment | Yes | No, so it has to be right first time |
| Editing | Built in | Usually none needed |
| Examples | CapCut, iMovie, TikTok Duet | Lookout, Apple Dual Capture on iPhone 17 |
What to look for in any reaction video app
- No watermark on the free version, or a clear price to remove it.
- No recording-length limit that cuts you off mid-reaction.
- Hands-free start, because reactions are ruined by someone reaching for the phone.
- Privacy: reaction videos are full of faces, often children's. Prefer apps that do not upload by default.
Our pick by situation
- Reacting to a YouTube clip: an editor with picture-in-picture.
- Reacting on TikTok: TikTok's own Duet or Stitch.
- Filming a real moment and the faces watching it: Lookout.