Sidecar is Apple's built-in way to use an iPad as a second display — excellent at what it is: more screen space at your desk, cable-or-nearby range, iPad only.
Apperture is a different shape of tool. It streams one Mac app's window to an iPhone or iPad anywhere on your private network — the next room, the couch, or over a VPN — with touch input mapped to that app.
Side by side
| Apperture | Sidecar | |
|---|---|---|
| What it is | A remote viewer/controller for a single Mac app | An extended (or mirrored) Mac display |
| Devices | iPhone and iPad | iPad only |
| Range | Anywhere on your private network, or remote over a VPN like Tailscale | Same desk — within ~10 meters of the Mac |
| Input | Touch drives the Mac app directly; iOS keyboard and menu access | Apple Pencil and keyboard; touch does not click Mac UI |
| Pricing | Free Mac host; first 15 connections free with full functionality, then a Pro unlock inside the iOS app (launch offer: one-time lifetime) | Free, built into macOS/iPadOS |
| Best for | Using or monitoring one Mac app away from the Mac | Extra screen real estate while you sit at the Mac |
Bottom line
If you're at your desk and want more pixels, use Sidecar — it's free and built in. When you walk away from the desk and still want eyes and hands on one Mac app, that's Apperture.