Privacy Policy

This Privacy Policy explains how the Engineer Tools app for Android (package com.ssbyte.engineer, the "App") handles information. The App is made by Secure System Bytes (SSByte) ("we", "us"), which is responsible for it.

Last updated: October 5, 2026

The short version

• Your measurements stay on your phone. The App reads the phone's motion and magnetic sensors to work as a bubble level, angle finder and compass. The readings, your settings and your calibration are processed and stored only on your device. We never receive them.
• No account. There is no sign-up or login. The App never asks for your name, email address, phone number, contacts, photos, files or location.
• Three Google services handle limited data: Google AdMob shows ads in the free version, Firebase Crashlytics sends crash reports, and Google Play Billing sells the optional Pro subscription. Each is described below.
• Made to be safe for children. Every ad request is marked as directed to children: ads are limited to general-audience content and are not personalised, and the App does not use the Android advertising ID.
• We do not sell your data, and we run no servers of our own that store information about you.

About the App

Engineer Tools turns a phone into everyday measuring tools: a bubble level (a circular level and horizontal and vertical vials, with sound guidance, two-point calibration, hold and auto-hold, and a flashlight button), an angle finder, a compass that points to magnetic north, a true-size ruler and an on-screen protractor. The tools work offline. The App is free with ads; Pro, an optional monthly subscription, removes the ads and unlocks every theme.

Data at a glance

Information that stays on your device

Motion and magnetic sensors

The App reads the accelerometer, the gyroscope (where the phone has one) and the magnetometer to measure tilt and the compass heading. The readings are processed in real time on your device. They are not saved, and they are never sent to us or to anyone else.

Settings, calibration and counters

The App saves these on your device:

• your settings: units, precision, response, level tolerance, sound guidance, auto-hold, theme and language;
• your calibration, which belongs to your phone's own sensor;
• a copy of Google Play's last answer about whether Pro is active, so the App knows at start-up, even offline;
• a few counters, such as how many times you have opened the App and when the rating request was last shown. The App uses them to pace ads and to decide when to ask for a rating.

None of this is sent to us. If you have turned on Android's backup for your device, Android may include the App's settings (but not the calibration, which is always excluded) in that backup, which is stored in your Google account under Google's terms. We cannot access it.

Flashlight

The flashlight button turns on the light next to the camera using Android's torch mode. The App does not open the camera, take pictures or record video, and it has no camera permission.

Compass

The compass shows magnetic north, measured by the phone's magnetic sensor. It does not use GPS or any other location service, and the App does not ask for location permission.

Advertising (Google AdMob)

The free version of the App shows ads from Google AdMob: a banner, and from time to time a full-screen (interstitial) ad at a natural break. Ads never appear when the App starts. Pro removes all ads.

Ads for a general audience that includes children. The App is for everyone, including children (its target audience on Google Play is ages 6 and over). Because the App does not ask anyone's age, it treats every user as a child:

• every ad request is tagged for child-directed treatment (the setting Google provides for the US Children's Online Privacy Protection Act, COPPA) and as coming from a user under the age of consent, and is limited to ads rated G (suitable for general audiences);
• ads are therefore not personalised: Google turns off interest-based ads and remarketing for these requests;
• the App does not use the Android advertising ID: the advertising ID permission is removed from the App, and Google does not transmit the advertising ID with child-directed ad requests;
• the App does not show a consent pop-up for ads, because every user is treated as under the age of consent.

What the Google Mobile Ads SDK collects. To show and measure ads and to prevent fraud, the Google Mobile Ads SDK in the App automatically collects and sends to Google:

• the device's IP address, which may be used to estimate the general location of the device (not your precise location);
• product interactions, such as app launches, taps and ad views;
• diagnostic information about the performance of the App and the SDK, such as launch time, hang rate and energy use;
• the App Set ID, an identifier that Android gives to the apps of one developer on a device (used instead of the advertising ID).

Google uses this data for advertising, analytics and fraud prevention. It is encrypted in transit using TLS. Google receives it as the ad network that serves the App's ads and processes it under the Google Privacy Policy. We only see aggregated reports from AdMob, such as how many ads were shown; they do not identify you.

Learn more:

• How Google uses information from sites or apps that use its services
• Data collected by the Google Mobile Ads SDK

Crash reports (Firebase Crashlytics)

If the App crashes, Firebase Crashlytics, a Google service, sends a crash report so that we can find and fix the problem. A report contains:

• the stack trace, the technical record of where in the App's code the crash happened;
• the state of the App and details of the device at the time of the crash, such as the phone model, Android version, orientation, free memory and storage;
• the App's version;
• installation identifiers created by Firebase (a Crashlytics installation ID and a Firebase installation ID). They identify one installation of the App, not you.

Crash reports do not contain your name, contacts, files, location or measurements. They are used only to fix bugs and make the App more stable, are encrypted in transit using HTTPS, and are processed by Google as our service provider. Firebase keeps crash reports for 90 days, then starts deleting them from its systems. Learn more: Firebase privacy and security.

The Pro subscription (Google Play Billing)

Pro is optional. It is sold, billed and managed by Google Play:

• What you get: Pro removes all ads and unlocks every theme. Every measuring tool is free without Pro.
• Price and renewal: Pro is an auto-renewing monthly subscription. The price is US$1.99 a month in the United States; in other countries Google Play shows the local price, including any taxes, before you subscribe. It renews every month until you cancel.
• Free trial: new subscribers get a 3-day free trial. Google Play charges you when the trial ends, then every month. If you cancel before the trial ends, you pay nothing.
• Cancelling: you can cancel at any time in the Google Play Store (your profile picture, then Payments & subscriptions, then Subscriptions), or from the App (Settings, then Manage subscription, shown while Pro is active). After you cancel, Pro stays on until the end of the current period, and the subscription does not renew. See Cancel, pause, or change a subscription on Google Play.
• Refunds are handled by Google Play under its refund policies.

We never see your card or other payment details. Google Play tells the App only whether a Pro subscription belongs to the Google account on the device and whether it will renew, so the App can turn Pro on or off. Google processes your purchase under the Google Privacy Policy.

Rating request (Google Play)

From time to time the App may ask you to rate it, using Google Play's in-app review card or a card in the App that opens the App's page on Google Play. The in-app review is shown and handled by Google Play. The App does not receive your rating, your review or any information from it.

Permissions

The App declares these Android permissions:

• Internet (INTERNET) and network state (ACCESS_NETWORK_STATE): to load ads, to check your Pro subscription with Google Play and to send crash reports. The measuring tools work without a connection.

The App removes the advertising ID permission (com.google.android.gms.permission.AD_ID), so it cannot read the advertising ID. It does not ask for access to your camera, microphone, location, contacts, photos or files; the flashlight uses Android's torch mode, which needs no permission. The Google libraries in the App (Google Play Billing, the Google Mobile Ads SDK and Firebase) may add standard technical permissions they need to work, such as Google Play's billing permission; none of them gives access to your camera, microphone, location, contacts, photos or files.

Children

Engineer Tools is suitable for children. It is made for a general audience that includes children, and its target audience on Google Play is ages 6 and over.

• The App has no account, no chat and no way for users to post or share content.
• All ads are child-directed, limited to general-audience (G-rated) content and not personalised, and the App does not use the advertising ID (see Advertising).
• The App never asks for a name, email address, phone number, photo, location or any other personal information.
• We do not knowingly collect personal information from children. The only data that leaves the device is the automatic data described above: what the Google Mobile Ads SDK and Firebase Crashlytics collect, and the subscription status handled by Google Play.
• Pro can only be bought through Google Play, where Google's parental controls and purchase approvals apply.

Parents and guardians: if you believe your child has provided personal information through the App, or you would like data about your child's use of the App deleted, email info@ssbyte.com. We will delete any such information we hold or can delete (for example, crash reports in Firebase Crashlytics that we can identify) and explain how to remove the rest. Uninstalling the App deletes everything it stored on the device.

Sharing and selling

We do not sell personal information, and we do not share it for targeted advertising. The data described above is shared only with Google: as our service provider for crash reports (Firebase Crashlytics) and purchases (Google Play Billing), and as the ad network that serves the App's ads (Google AdMob).

Security

Everything the App sends over the internet goes through Google's software development kits and is encrypted in transit (TLS/HTTPS). Data stored on your device is kept in the App's private storage, which Android protects from other apps.

How long data is kept, and how to delete it

• On your device: settings, calibration, the Pro status copy and the counters stay until you clear the App's storage or uninstall the App. Uninstalling deletes them. A copy of your settings in your Android backup is managed in your Google account.
• Crash reports: Firebase Crashlytics keeps them for 90 days, then starts deleting them from its systems.
• Advertising data: the Google Mobile Ads SDK data is kept and deleted by Google under its own rules. See How Google retains data it collects.
• Subscription records: Google Play keeps purchase and subscription records under Google's policies and legal obligations (for example, for tax).
• Requests: to ask what data relates to your use of the App, or to ask for it to be deleted, email info@ssbyte.com. We hold no personal data on servers of our own; we will delete what we can (such as identifiable crash reports) and tell you how to contact Google about data that Google processes. Depending on where you live, you may also have rights to access, correct or delete personal data, to object to its processing, and to complain to your data protection authority.

Changes to this policy

We may update this policy when the App or the services it uses change. The current version is always at this address, and the "Last updated" date at the top shows when it last changed. Please check it from time to time.

Contact

Questions about this policy or about your data:

Secure System Bytes (SSByte) · info@ssbyte.com · ssbyte.com