Install and check your phone¶
Get the app¶
Nightmare is not on the Play Store. It is installed from its GitHub releases page:
- On your phone, open the latest release.
- Under Assets, tap
nightmare-<version>.apkto download it. - Open the downloaded file. Android will ask you to allow installs from your browser or file manager the first time — allow it, go back, and tap Install.
Updating
A newer APK installs straight over the old one. Your models, saved flows and results are
kept. Do not uninstall first — uninstalling deletes everything stored inside the app,
including downloaded models (unless you moved them to Download/Nightmare, see
Settings).
Check what your phone can run¶
Tap the ⓘ button at the top right of the main screen. It shows your chip, its NPU generation ("HTP arch", for example v79 for a Snapdragon 8 Elite) and its fast on-chip memory ("VTCM").
You rarely need these numbers yourself: every model row in Models and every card in Flows already says when your phone cannot run it, and why. The table on the home page is the short version.
A chip the app does not recognise
A brand-new Snapdragon may not be in the app's tables yet. The app then offers you everything rather than hiding it, and measures the chip when you open the ⓘ panel. If a model then fails to start, that is the reason — please report the chip name.
Let it run in the background¶
A render can take from a few seconds to several minutes. Some phones (Samsung especially) stop apps that are not on screen to save battery, which ends the render.
If Settings → General shows a card titled Keep rendering in the background, tap Allow in background. That is all it needs; the card disappears once it is allowed.