This Privacy Policy explains how personal data is collected, used and protected in connection with the website appscaling.monster (the "Website") and the Stud Detector mobile application for Android, distributed via Google Play (package com.stud_detector) (the "App"). Together they are referred to as the "Services".

Please read this Policy together with our Terms of Service.

1. Who is responsible for your data (Data Controller)

The Services are operated by Yurii Ivanyshyn, a private individual resident in Poland, acting as the controller of your personal data within the meaning of Regulation (EU) 2016/679 (the "GDPR").

All privacy matters — including requests for our postal correspondence address — are handled directly at contact@checkengine.space. We have not appointed a Data Protection Officer, as we are not required to do so.

2. Short summary

We do not sell your personal data, we do not share it with data brokers, and we do not use it for advertising networks.

3. The Website

The Website is a static informational page. It has no contact forms, no user accounts, no analytics scripts, no advertising and no cookies other than those strictly necessary for the page to be delivered to you.

Like every website on the internet, our hosting provider automatically records technical connection data in server logs: IP address, date and time of the request, the page or file requested, browser type / user-agent and operating system, and the referring website (if any).

• Purpose: delivering the Website, ensuring its security and stability, detecting and preventing abuse and attacks.
• Legal basis: Art. 6(1)(f) GDPR — our legitimate interest in operating a secure and functioning website.
• Retention: kept by our hosting provider for a maximum of 30 days and then deleted or anonymised, unless a longer period is required to investigate a specific security incident.
• Hosting provider: Vercel Inc., acting as our processor under a data processing agreement.

If we ever add cookies, analytics or a contact form to the Website, this Policy will be updated before those features go live and — where required — your consent will be requested first.

4. Data processed only on your device (never sent to us)

The core function of the App is to detect anomalies in the magnetic field near a wall. The following data never leaves your device and is never accessible to us:

• Magnetometer and motion-sensor readings — read continuously while you scan and processed locally by the detection engine. They are held in memory only for the duration of the scan.
• Camera image — where the App shows a live camera view behind the scanning interface, frames are rendered on-screen in real time. Nothing is captured, saved, photographed, recorded or uploaded. The camera permission is optional and the App remains usable if you deny it.
• Calibration values and app settings — stored in the App's private storage on your device.
• Scan records stored in the App's local database, if you use features that save them.

All of this data is removed when you uninstall the App or clear the App's data in Android settings. Because it never reaches us, we cannot access, export or delete it on your behalf.

5. Data collected in the App

The App uses services provided by Google. Depending on the service, Google acts as our processor or as an independent controller (see Section 6).

5.1 Firebase Analytics (usage statistics)

What: pseudonymous app-instance identifier, events describing how the App is used (e.g. screen views, onboarding steps completed, a scan started, the paywall shown), device model, operating system version, device language, app version, and an approximate location (country/region) derived from the IP address. The IP address is not stored by us and is used by Google only for coarse geo-resolution.

Why: to understand which parts of the App are used and where users get stuck, so we can improve the product.

Legal basis: Art. 6(1)(a) GDPR — your consent, requested in the App. If you do not consent, or you later withdraw consent, these statistics are not collected. Withdrawing consent does not affect the lawfulness of processing carried out before withdrawal.

5.2 Firebase Crashlytics (crash and stability reports)

What: crash stack traces, App version, device model, operating system version, free memory/storage state at the moment of the crash, and a pseudonymous installation identifier. Crash reports do not contain your sensor data, camera images, contacts, files or location.

Why: to identify and fix crashes and defects. Legal basis: Art. 6(1)(a) GDPR — your consent, requested in the App.

5.3 Firebase Remote Config

What: a pseudonymous installation identifier, App version and device data, used to deliver configuration values (such as which pricing screen variant to show).

Why: to configure and test App features without shipping a new release. Legal basis: Art. 6(1)(f) GDPR — our legitimate interest in operating and improving the App.

5.4 Google Play Install Referrer

What: information provided by Google Play about how the App reached your device (e.g. the campaign or referral parameters attached to the install), read once at first launch.

Why: to measure which channels bring users to the App. Legal basis: Art. 6(1)(a) GDPR — your consent, where required.

5.5 Purchases and subscriptions (Google Play Billing and RevenueCat)

All purchases are made through Google Play, not through us. Google is the seller of record and processes your payment. We never receive or store your card number, bank details, billing address or full name from a purchase.

We do receive the status of your entitlement (for example: whether an active subscription exists, its type and expiry, and a purchase token used to verify it). We use this solely to unlock paid features and to handle support and refund enquiries.

To manage subscriptions we use RevenueCat (RevenueCat, Inc., USA), acting as our processor. RevenueCat sits on top of Google Play Billing and validates purchase receipts, retrieves the available plans and prices, restores previous purchases and computes whether your entitlement is active.

What is sent to RevenueCat: a randomly generated, anonymous app-user identifier created by the SDK on your device, the Google Play purchase token and receipt for a purchase you make, the resulting subscription/entitlement state, and basic technical data (app version, platform, country/store, and the IP address inherent to any internet request).

What is NOT sent: the App runs RevenueCat in anonymous mode — there are no accounts and no login, so we do not create, collect or transmit any name, e-mail address, advertising identifier or other identity of yours to RevenueCat. RevenueCat never receives your card or bank details, and it never receives your sensor readings, camera images or scan data.

Legal basis: Art. 6(1)(b) GDPR — performance of the contract between you and us for the provision of paid App features. Google's own processing of your payment data is governed by Google's Privacy Policy and the Google Play Terms of Service; RevenueCat's processing is described in the RevenueCat Privacy Policy.

5.6 Support correspondence

If you write to us by e-mail, we process your e-mail address, the content of your message and any information you choose to include.

Legal basis: Art. 6(1)(f) GDPR — legitimate interest in answering enquiries; and Art. 6(1)(b) GDPR where your message concerns a contract with us. Retention: up to 24 months after the matter is closed, or longer where needed to establish, exercise or defend legal claims.

6. Who we share data with (recipients)

We disclose personal data only to:

We do not sell, rent or trade personal data, and we do not share it for third-party advertising or profiling.

7. International transfers

Our providers may process data outside the European Economic Area, in particular in the United States. Where this happens, the transfer is protected by the European Commission's Standard Contractual Clauses (Art. 46(2)(c) GDPR) and/or an adequacy decision (e.g. the EU–US Data Privacy Framework, where the recipient is certified), together with supplementary technical and organisational measures. You may request a copy of the relevant safeguards by writing to us.

8. Retention

• Website server logs: up to 30 days.
• Analytics data (Firebase): up to 14 months, then automatically deleted or aggregated.
• Crash reports: up to 90 days.
• Purchase / entitlement records: for the duration of the subscription plus the period required by tax and accounting law in Poland (generally 5 years from the end of the tax year) and by limitation periods for claims.
• Support e-mails: as described in Section 5.6.
• On-device data: until you delete it or uninstall the App.

9. Your rights

Under the GDPR you have the right to:

• access your data and obtain a copy (Art. 15);
• rectify inaccurate or incomplete data (Art. 16);
• erase your data — the "right to be forgotten" (Art. 17);
• restrict processing (Art. 18);
• data portability (Art. 20);
• object to processing based on legitimate interest, at any time, on grounds relating to your particular situation (Art. 21);
• withdraw consent at any time, without affecting the lawfulness of processing before withdrawal (Art. 7(3));
• lodge a complaint with a supervisory authority.

To exercise any of these rights, e-mail contact@checkengine.space. We will respond within one month; if the request is complex we may extend this by two further months and will tell you why.

Because the App has no accounts and the identifiers we hold are pseudonymous, we may need additional information from you (for example your App instance ID, available in the App's settings, or your Google Play order number) to locate your data. If we cannot identify you, we may be unable to fulfil the request (Art. 11 GDPR).

Supervisory authority in Poland: Prezes Urzędu Ochrony Danych Osobowych (President of the Personal Data Protection Office), ul. Stawki 2, 00-193 Warszawa, Poland — uodo.gov.pl. You may also complain to the authority in your own EU country of residence.

How to switch analytics off: open the App → Settings → Privacy and turn off analytics and crash reporting. You may also uninstall the App at any time, which stops all collection.

10. Automated decision-making

We do not carry out automated decision-making producing legal effects concerning you, and we do not create individual behavioural profiles within the meaning of Art. 22 GDPR.

11. Children

The Services are not directed at children. The App is intended for users aged 16 and over (or the minimum age at which consent to data processing is valid in your country, if that age is higher). We do not knowingly collect data from children. If you believe a child has provided us with personal data, contact us and we will delete it.

12. Security

We apply appropriate technical and organisational measures, including encrypted transport (HTTPS/TLS), keeping sensitive processing on-device, using reputable providers under data processing agreements, and limiting access to data to what is necessary. No method of transmission or storage is completely secure, and we cannot guarantee absolute security.

13. Changes to this Policy

We may update this Policy — for example when we add a feature or change a provider. The "Last updated" date at the top always shows the current version. If a change is material, we will give notice on the Website and, where appropriate, in the App before it takes effect. Where a change requires your consent, we will ask for it.

14. Contact

Yurii Ivanyshyn, Poland
E-mail: contact@checkengine.space

1. Who we are and what these Terms cover

These Terms of Service (the "Terms") form a binding agreement between you and Yurii Ivanyshyn, a private individual resident in Poland ("we", "us", "our"), contactable at contact@checkengine.space. Our postal correspondence address is available on request at that address.

These Terms govern your use of the website appscaling.monster (the "Website") and the Stud Detector Android application (the "App"), together the "Services". Our Privacy Policy forms part of these Terms.

2. Acceptance

By visiting the Website, or by downloading, installing or using the App, you confirm that you have read, understood and accept these Terms. If you do not accept them, do not use the Services. If you use the App on behalf of a business, you confirm you are authorised to bind that business to these Terms.

3. Eligibility

You must be at least 16 years old to use the Services, and at least 18 years old (or otherwise legally capable of entering into a contract in your jurisdiction) to purchase a subscription. Any DIY work involving tools, electricity or structural elements should only be carried out by an adult who is competent to do so.

4. What the App actually does — and what it does not

The App uses your device's magnetometer (and, where available, motion sensors) to detect local changes in the magnetic field. Studs made of wood are not magnetic and are not detected directly; the App can only indicate the possible presence of ferromagnetic material — such as nails, screws, drywall fasteners, metal framing, pipes or conduit — which is often, but not always, located near a stud.

The App expressly does NOT:

• detect wood, plastic, PEX or PVC pipes, fibre-optic cable, or non-ferrous metal reliably or at all;
• measure the depth of anything;
• identify the material of what it detects (it cannot tell copper from rebar from a screw);
• guarantee that a live electrical cable will be found. Any live-wire indication is a best-effort estimate based on mains-frequency interference, is unavailable on many devices, and must never be treated as a substitute for a certified voltage detector;
• work on every device. Results depend on the quality, position and sample rate of your phone's sensor, wall material and thickness, magnetic interference, phone cases, and how the device is moved. Some devices have no suitable magnetometer at all and cannot run the App.

Results are indicative estimates only.

5. Safety disclaimer — no reliance

This is the most important term in this agreement, and it must be read together with the ABSOLUTE DISCLAIMER above.

5.1 The Services are provided for general information and convenience only. They are not a professional survey, not an inspection, not an electrical test, and not advice of any kind.

5.2 You must not rely on the App as the sole or primary basis for any decision to drill, cut, nail, screw, saw, demolish or otherwise interfere with any wall, floor, ceiling or structure.

5.3 You accept full and sole responsibility for any work you carry out and for deciding whether it is safe to proceed. Drilling into a wall can cause electrocution, fire, flooding, gas escape, structural damage, serious injury or death.

5.4 The App must not be used in any professional, industrial, medical, emergency, utility-location, mining or life-critical context, or anywhere a failure to detect an object could cause injury or significant damage.

5.5 Nothing in this Section limits any liability that cannot lawfully be limited (Section 12.3).

6. Licence to use the App

6.1 Subject to these Terms, we grant you a limited, personal, non-exclusive, non-transferable, revocable licence to install and use one copy of the App on devices you own or control, for your own non-commercial purposes.

6.2 The App is licensed, not sold. We and our licensors retain all rights, title and interest in the Services.

6.3 You must not:

• copy, modify, translate, adapt or create derivative works of the App;
• reverse-engineer, decompile or disassemble the App, or attempt to derive its source code or detection algorithms, except to the extent this cannot be prohibited under Art. 6 of Directive 2009/24/EC or applicable Polish law;
• rent, lease, lend, sell, sublicense, distribute or make the App available to third parties;
• circumvent, disable or interfere with any security, licensing or payment mechanism, including unlocking paid features without payment;
• use the Services unlawfully, or in a way that could damage, disable or impair them;
• scrape, crawl or bulk-download the Website, or use automated systems against it;
• remove or obscure any proprietary notices.

6.4 We may suspend or terminate your licence immediately if you materially breach these Terms.

7. Purchases, subscriptions and cancellation

7.1 Where you buy. Paid features are sold exclusively through Google Play. Google is the seller of record and processes your payment. Your purchase is therefore also subject to the Google Play Terms of Service.

7.2 Subscription management. We use RevenueCat (RevenueCat, Inc.) as our subscription-management provider. RevenueCat sits on top of Google Play Billing and handles receipt validation, price and offer retrieval, restoring purchases and determining whether your subscription entitlement is active. RevenueCat is not a seller and not a payment processor: it never receives your card details, and it does not change who you are contracting with for the purchase (Google) or with for the App itself (us). The App uses RevenueCat in anonymous mode — no account, login or identity of yours is created or transmitted (see the Privacy Policy, Section 5.5).

7.3 Plans. The App offers a weekly plan and a yearly plan. The current plans, prices, currency, applicable taxes and any trial or introductory terms are those displayed in the App and in Google Play at the moment of purchase, and those displayed prices prevail over any figure mentioned elsewhere. Any free-trial badge is shown only when the offer actually applies to your account and store; if no introductory offer is available to you, none is granted.

7.4 Auto-renewal. Subscriptions renew automatically at the end of each billing period at the then-current price, and your Google Play payment method is charged, unless you cancel at least 24 hours before the end of the current period.

7.5 How to cancel. Cancel at any time in Google Play → Subscriptions, or at play.google.com/store/account/subscriptions. Uninstalling the App does not cancel a subscription. Cancellation takes effect at the end of the current paid period; you keep access until then.

7.6 Refunds. Refunds are handled by Google under Google Play's refund policy. We have no ability to process a Google Play payment or issue a refund directly, but we will assist you where we reasonably can — write to contact@checkengine.space. This does not affect your statutory rights below.

7.7 Consumer right of withdrawal (EU/EEA). As a consumer you normally have 14 days to withdraw from a distance contract for digital content without giving a reason. By starting to use the paid features immediately, you expressly request immediate performance and acknowledge that you thereby lose your right of withdrawal once performance has begun with your consent (Art. 16(m) of Directive 2011/83/EU; Art. 38 of the Polish Consumer Rights Act of 30 May 2014). Where the right of withdrawal still applies, exercise it via Google Play or by writing to us.

7.8 Price changes. We may change prices for future billing periods. You will be notified in advance in accordance with Google Play's rules, and you may cancel before the change takes effect. Price changes never apply retroactively to a period already paid for.

7.9 Conformity. Where the App is supplied as paid digital content to a consumer in the EU, you have statutory rights to a product that conforms with the contract, and to have any lack of conformity brought into conformity, or to a price reduction or termination, under Directive (EU) 2019/770 as implemented in Poland. Nothing in these Terms excludes those rights.

8. Availability and changes

8.1 We aim to keep the Services available, but they are provided on an "as available" basis. We do not guarantee uninterrupted or error-free operation.

8.2 We may at any time modify, update, suspend, restrict or discontinue the Services or any feature, including for maintenance, security or legal reasons. Where a change materially and negatively affects a paid feature you are currently paying for, we will notify you and, where the law requires, allow you to terminate and receive a proportionate refund for the unused period.

8.3 We may require you to install updates. Older versions may stop working.

8.4 Continued operation of the App depends on your device, its sensors, its operating system and third-party platforms which we do not control.

9. Third-party services

The Services rely on third parties, including Google Play, Google Firebase, RevenueCat and our hosting provider. Their terms and privacy policies apply to their own services. We are not responsible for third-party content, availability or acts, and any link on the Website to an external site is provided for convenience only and is not an endorsement.

10. Intellectual property

All content of the Services — including the source code, detection algorithms, interface design, graphics, animations, text, trade marks, logos and the name "Stud Detector" — is owned by us or our licensors and protected by copyright and other laws. No rights are granted to you except those expressly set out in Section 6.

Feedback. If you send us ideas, suggestions or feedback, you grant us a non-exclusive, worldwide, perpetual, irrevocable, royalty-free licence to use them for any purpose without obligation or compensation to you. Please do not send us anything you consider confidential.

11. Disclaimer of warranties

11.1 To the fullest extent permitted by applicable law, the Services are provided "AS IS" and "AS AVAILABLE", without warranties of any kind, whether express, implied or statutory, including any implied warranty of merchantability, satisfactory quality, fitness for a particular purpose, accuracy or non-infringement.

11.2 In particular, we do not warrant that:

• the App will detect any given object, or that any detection is accurate, complete or correctly located;
• the absence of a detection means the absence of an object;
• the App is compatible with, or will perform on, your particular device;
• the Services will be uninterrupted, secure or free of defects.

11.3 Nothing in this Section affects the mandatory statutory rights of consumers (Sections 7.9 and 12.3).

12. Limitation of liability

12.1 To the fullest extent permitted by applicable law, we shall not be liable for:

• any property damage — including damage to walls, floors, ceilings, wiring, plumbing, gas installations, heating, insulation, cabling or the contents of a building — arising from drilling, cutting or other work carried out with reference to the App;
• any indirect, incidental, special, consequential or punitive damages;
• loss of profit, revenue, business, opportunity, data or anticipated savings;
• the cost of repair, remediation or professional services;
• any loss arising from your reliance on a detection result, or from the absence of a detection result;
• any loss arising from third-party services, device or sensor malfunction, or your failure to follow Section 5.

12.2 Where our liability is not otherwise excluded, our total aggregate liability to you for all claims arising out of or in connection with the Services is limited to the greater of (a) the amount you actually paid us for the App in the 12 months immediately before the event giving rise to the claim, and (b) EUR 50 (or its equivalent).

12.3 Nothing in these Terms excludes or limits our liability for: death or personal injury caused by our negligence; fraud or fraudulent misrepresentation; intentional misconduct (wina umyślna); or any other liability that cannot lawfully be excluded or limited under Polish law or under the mandatory consumer-protection law of your country of residence. If you are a consumer, your mandatory statutory rights always prevail over any conflicting provision of these Terms.

12.4 The limitations in this Section reflect the fact that the App is provided at low cost as an informational aid, and are an essential basis of the bargain between us.

13. Your responsibility and indemnity

You are solely responsible for how you use the Services and for any work you carry out. You acknowledge that drilling into walls without proper verification carries extreme hazards, including striking live electrical wires, gas pipes or water lines, which can lead to death, physical injury or catastrophic property damage.

To the extent permitted by law — and, if you are a consumer, only where the claim arises from your own breach of these Terms or unlawful conduct — you agree to indemnify and hold us harmless from any third-party claims, damages, losses and reasonable legal costs arising from your use of the Services, your breach of these Terms, or any work you performed.

14. Term and termination

These Terms apply for as long as you use the Services. You may terminate at any time by ceasing use and uninstalling the App (and cancelling any subscription per Section 7.5). We may suspend or terminate your access for material breach, unlawful use, or where required by law. Sections 5, 10, 11, 12, 13, 15 and 16 survive termination.

15. Governing law and disputes

15.1 These Terms and any dispute arising out of them are governed by the law of the Republic of Poland, excluding its conflict-of-law rules and the UN Convention on Contracts for the International Sale of Goods.

15.2 If you are a consumer resident in the EU/EEA, this choice of law does not deprive you of the protection of the mandatory provisions of the law of your country of residence, and you may bring proceedings in the courts of your country of residence under Regulation (EU) No 1215/2012.

15.3 If you are not a consumer, the exclusive place of jurisdiction is the court competent for our place of residence in Poland.

15.4 Out-of-court dispute resolution. We would prefer to resolve any issue directly — please write to contact@checkengine.space first and we will try to answer within 14 days. Consumers in Poland may also seek assistance from a powiatowy (miejski) rzecznik konsumentów, a consumer organisation, or the Trade Inspection (Wojewódzki Inspektorat Inspekcji Handlowej). We are not obliged to, and do not undertake to, participate in any particular alternative dispute resolution scheme.

16. General

• Changes to these Terms. We may amend these Terms, for example to reflect new features or legal requirements. The current version is always published on this page. Material changes will be notified on the Website and, where appropriate, in the App at least 14 days before they take effect. If you do not accept a change, your remedy is to stop using the Services and cancel any subscription. Changes never apply retroactively to a completed purchase.
• Severability. If any provision is held invalid or unenforceable, the remainder stays in force and the invalid provision is replaced by a valid one that most closely reflects its intent.
• No waiver. Failure to enforce a provision is not a waiver of it.
• Assignment. You may not assign your rights under these Terms. We may assign them to a successor in connection with a transfer of our business, provided your rights are not diminished.
• Entire agreement. These Terms and the Privacy Policy constitute the entire agreement between you and us regarding the Services.
• Language. These Terms are drawn up in English. Any translation is provided for convenience; in case of conflict, the English version prevails, unless mandatory consumer law in your country provides otherwise.
• Force majeure. We are not liable for failures caused by events beyond our reasonable control.

17. Contact

Yurii Ivanyshyn, Poland
E-mail: contact@checkengine.space

1. Overview

This privacy policy covers your utilization of the mobile application Habit Rise 14, a structured 14-day habit development tracker built to help you master new daily routines.

2. Local Storage and Data Collection

Your habits, checklists, progression charts, and configuration data are stored strictly in your device's internal storage. We do not use remote servers to host or sync your custom list of habits. All of your structural daily records remain private to you.

3. Push Notifications

To support consistency and notify you of habit due dates, the Application requires local notification privileges. These reminders are planned and delivered entirely locally by your device's operating system.

4. Advertising and Analytics

To support our service and maintain free offerings, we might utilize monetization platforms (such as Google AdMob) or analytical tools. These systems process anonymous device identifiers according to your operating system permissions.

5. Support Queries

If you submit an inquiry to our support email, we will only use your email address to provide assistance. Contact us at contact@checkengine.space.

1. Use of the App

By accessing Habit Rise 14, you agree to these Terms. You are solely responsible for ensuring your habits align with healthy and safe physical practices.

2. Local Data Risks

Because Habit Rise 14 uses local offline storage, removing the app, clearing cache, or experiencing system crashes may result in permanent data deletion. We are not liable for any lost logs or streaks.

3. Subscription and Billing (If Applicable)

Any transactions or subscriptions processed are governed directly by App Store or Google Play policies and processing engines. Cancellation and refund workflows must be initiated through your store account.