LunaMixer: Per-App Volume

Most volume-switching apps change the whole phone's volume to match whichever app is in front.
LunaMixer holds several apps that are playing at once, each at its own level, on its own.

■ What it does
・Apps that are making a sound appear in the list on their own.
・Several volumes can be adjusted separately at the same time.
・A floating bubble reaches it from inside any app.
・Closing the app puts every volume back the way it was.

■ No root
Your phone does not need to be modified. LunaMixer uses Wireless debugging, which is already part of Android.

■ No computer, no cable
Setup happens entirely on this phone. Every step is explained on screen, and nothing has to be plugged into a computer.
You only do this once. After that, opening the app is all it takes.

■ A restart does not undo it
Restarting your phone leaves the pairing in place. Turn wireless debugging on, tap "Turn volume control back on", and you are back. The six-digit code is not needed again.

■ About network use
Changing volumes never involves a connection.
Nothing about what you listened to, or which apps you have, is sent anywhere.
There are no ads. In-app purchases go through Google Play's billing system, and the billing library built into the app does contact Google's servers.

■ Price
Paid once. There is no subscription.
A three-day trial runs first. The trial is there so you can confirm that setup works on your particular phone.
The steps look slightly different from one manufacturer to another, so please try it before buying.

■ If it does not work
・Apps that produce sound in unusual ways (some games) may not respond.
・Some phones already offer something similar through the manufacturer's own app.

■ Requirements
・Android 11 or later
・Wi-Fi, for setup only. A network with no internet access is fine

■ Setup guide
Every step of the setup, explained screen by screen.
https://hystudio21.com/appvolume/index.en.html

■ Seller information
Notice under Japan's Specified Commercial Transactions Act
https://hystudio21.com/legal/tokushoho.html