Kai Muay Privacy Policy
Effective September 14, 2026. Published at kaimuay.app and linked from Google Play. Written to be true today: if the app ever starts syncing or measuring how it is used, this page changes before the code does.
The short version
Kai Muay has no internet permission: there is no account, no server, no analytics and no advertising, and the app cannot send anything on its own. Two things can leave your phone, and both depend on you: what you export by hand to an app of your choice, and — if you have Android Backup turned on — your settings, your progress and your session summaries, which the system stores in your Google account, encrypted with your phone’s screen lock. The sensor recordings never go to any server.
What the app stores, and where
Everything lives in the app’s private storage on your device, in the folder
Android/data/app.kaimuay/files/:
- Sensor recordings (
sessions/raw_*.csv.gz): accelerometer and gyroscope while the phone is mounted on the bag or lying on the floor, used to count and measure strikes and jumps. They are large files (10–15 MB per class) and expire on their own: by default the last ten are kept (change it in Settings › Keep recordings). - A summary of each session (
resumenes/meta_*.json): strikes, jumps, peaks, pace, which class it was and its grade. This is what History, Statistics and Progress show, and it stays. About 40 KB per class. - Settings and progress: your stance, the measurement setup, which classes you have completed, your streak, whether the app has already asked for notification permission, and — for reminders — the time you usually train and when the app last reminded you, both calculated on your phone from your own sessions.
- Phone model and Android version, inside each summary, to know how many g your sensor can read. There are no device identifiers and no identifiers of you.
No personal data is stored: no name, no email, no location, no contacts, no photos, no audio. The app does not use the camera or the microphone.
What the app does not do
- It does not send anything on its own. The app does not declare the internet permission; Android will not let it open a connection even if it tried. The only thing that travels is Android Backup, which the system does, not the app, and which is explained below.
- It has no account and no sign-in.
- It does not measure how you use it and does not send crash reports.
- It shows no advertising and shares nothing with third parties.
Permissions it asks for, and why
| Permission | Why |
|---|---|
| High-frequency sensors | To read the accelerometer and gyroscope at the phone’s maximum rate: that is what measures the strike. |
| Foreground service (health) | To keep recording with the screen locked during a class. |
| Notifications | The “recording” notice while a recording lasts, and the training reminders: the class that is due, at the time you usually train, calculated on your phone. Turn them off in Settings › Reminders. If you deny it, the app records all the same, just without the notice. |
| Boot completed | To schedule the reminder again when the phone restarts: Android clears alarms when it shuts down. |
Android Backup
If Android Backup is on in your phone (Settings › Google › Backup), the system — not the app — stores your apps’ data in your Google account and restores it when you get a new phone, reinstall the app or do a factory reset. From Kai Muay:
- It uploads: your settings (stance, voice, screen, reminders, how many recordings to keep), your progress along the Path and the summary of each session. This is what makes your history, your statistics and your progress come back whole on the new phone.
- It does not upload: the sensor recordings. They are large, they expire on their own, and the app never reads them again once the summary is written. It also leaves out what belongs to this phone and not to you: whether you were already asked for notification permission, so that the new phone asks again.
- Only with a screen lock: the app asks Android to make the backup only if it can be encrypted with your phone’s lock (PIN, pattern or password). Without a lock, there is no cloud backup. Google encrypts the backup in transit and, on top of that, with that lock.
- When moving to a new phone by cable or Wi-Fi, which Android offers when you set one up, the recordings go too (on Android 12 or later; before that, the same as to the cloud): that path never touches a server.
- The backup is yours, in your Google account, and Google’s privacy policy covers it. Kai Muay never sees or touches it. Turn it off in Settings › Google › Backup and delete it from your Google account dashboard. Uninstalling the app does not delete the backup already in your account.
Export and delete
- Export: in Settings › Export the last session, or when a class ends, you can share the recording with an app of your choice (email, Drive, anything). From then on, that copy belongs to you and to that app; Kai Muay does not see it.
- Delete: Settings › Keep recordings removes the raw files you no longer need; uninstalling the app deletes everything on the phone. Whatever remains in your Google account because of the backup is deleted from your account, not from the app.
Videos
Technique cards link to videos on YouTube and other platforms. When you open one, you leave Kai Muay and enter that platform, with its own privacy policy. Kai Muay does not embed the videos and does not know whether you watched them.
Children
Kai Muay is not directed to children under 13, and it collects no data from anyone, of any age.
This website
kaimuay.app is served by Cloudflare. It sets one cookie, lang, only if you pick a
language with the switch: it remembers that choice for six months and identifies nobody.
There are no analytics and no third-party scripts or fonts on the site. If that ever
changes, this section will say so, with a new date.
Changes
If the app ever starts doing something this page says it does not do (having its own account and syncing on its own, or measuring how you use it, for example), it will ask you inside the app before doing it, and this page will change with a new date.
Contact
Kai Muay is made by Binary Vektor LLC, 30 N Gould St Ste R, Sheridan, WY 82801, United States. Questions about this policy: hello@kaimuay.app.
This policy is also available in Spanish; if the two ever differ, the English version governs.