Privacy Policy
Spirit Level: Ruler & Angle · Last updated October 5, 2026
The app is a set of instruments: a level, a clinometer, a ruler and a magnifier. It has no accounts, no sign-in and no server of ours. This page describes the data that is involved anyway, and it describes what the app actually does — if the app changes, this page changes with it.
What stays on your device
Every measurement you keep, together with the unit you chose and the calibration of the ruler, is written to the app's own storage on your phone. It is never uploaded, never shared and never seen by us. Swiping a measurement away in History deletes it; deleting the app removes everything.
The camera
The magnifier is a live view, not a camera. It shows what the lens sees, enlarged, with the torch if you switch it on. Nothing is photographed, nothing is recorded and nothing is sent anywhere — the app has no access to your photo library and never asks for one.
The motion sensors
The level and the clinometer read the accelerometer and gyroscope, which is what tells them which way down is. Those readings live for as long as the dial is on screen and are not stored or transmitted.
Advertising
The app shows ads through Google AdMob, and that is how a free instrument pays for itself. To serve them, Google may collect and process:
- device advertising identifier
- IP address and the approximate location derived from it
- device type, OS version and language
- interactions with the ads shown
This is done by Google, not by us, and is covered by Google's privacy policy. We never receive it. One payment removes the ads, and with them this whole section.
Tracking permission
iOS asks whether the app may track you across other apps and websites. Declining changes nothing about the instruments — you simply see ads that are not personalised. You can change your answer at any time in Settings → Privacy & Security → Tracking.
Purchases
If you open the purchase screen or buy, Apple and RevenueCat handle the payment. RevenueCat receives an anonymous identifier for your device and whether the purchase is active. It never receives your name, your measurements or your payment details — we never see those either.
Usage analytics
The app records a small number of events about its own use — that it was opened, which instrument was opened, that the purchase screen was shown, that an ad was shown — to understand which parts are used. They are processed by Amplitude and carry no names, no measurements and no identifiers beyond the anonymous one for the device. They do not include where you are: the app never asks for your location and the service's own location lookup is switched off.
Children
The app is not directed at children under 13, and we do not knowingly collect data from them. It carries a 12+ rating because it shows third-party advertising.
Your rights
Because nothing of yours reaches us, there is nothing of yours for us to show you, correct or delete. Everything the app holds is on your phone: swipe a measurement away in History, or delete the app to remove the lot. For the advertising identifier, Settings → Privacy & Security → Tracking is the switch.
Changes
If this policy changes, the date at the top of this page changes with it.
Contact
Support and contact, or write to mr.dyuven@gmail.com.