Privacy Policy

1. Who we are and scope

The data controller for the ShinshuCore iOS app and this website is Przemysław Bocer, an independent developer based in Poland ("we"). You can contact us about privacy at support@bytechimera.com.

This policy explains how the ShinshuCore iOS app and this website handle information. ShinshuCore was designed under the privacy by design principle: the app requires no account and operates no server that could receive your data.

ShinshuCore guides the Interval Walking Training (IWT) protocol described by researchers at Shinshu University. It is a fitness timer and tracker. It is not a medical device, it does not diagnose, treat, or monitor any disease, and nothing in the app is medical advice.

2. Information handled by the app

ShinshuCore runs fully offline:

• No app data sent to us: the app requires no account and requests no name, email address, or advertising or device identifiers. Profile and workout data are processed on your device, as described below. Support emails are handled separately.
• No external servers: the app has no backend or API that receives your workouts, heart rate, steps, or location. Core walking features work offline. Opening a website link or sharing an export uses the destination service you choose.
• No analytics or ads: no third-party analytics tools, no crash-reporting SDKs, no ad networks, no third-party SDKs of any kind.
• No tracking: we do not track you across apps or websites, so the app never asks for App Tracking Transparency permission.

3. Where your data is stored

The app stores settings and workout history in its private on-device storage. Profile settings such as age and height are stored locally and are used for features such as estimated maximum heart rate and walking estimates. They are not sent to us. Session and weekly-progress snapshots are shared locally with its widget through an App Group. With your permission, workouts are also saved to Apple Health. ShinshuCore does not run its own cloud sync service; device backups may include app data according to your Apple backup settings.

Apple Health data may sync through iCloud according to your Apple settings; we do not receive a copy. App history remains until you delete sessions or remove the app. Deleting the app does not delete previously saved Apple Health entries, files you exported, or existing device backups. Manage those separately in Health, your chosen file destination, and your Apple backup settings. See Apple’s guide to managing Health data.

4. Device permissions and system integrations

• Health (read): the app can request heart rate only. Steps and cadence come from the iPhone motion sensors, and distance comes from location while a workout runs. Heart-rate readings require a source that writes to Apple Health. You can decline access and still use the interval timer.
• Health (write): the app can request permission to save your finished walking workouts. Health data is used only for the walking and fitness features you enable, never for advertising, marketing, or data brokerage. Other apps can access Health entries only according to the permissions you give them.
• Motion & Fitness: used to count steps and cadence, and calculate distance and pace estimates where available. Processed on device only.
• Location (while in use): used to calculate walking distance during an active session and to keep the workout running while the screen is locked. Coordinates are used for distance calculation on the device, are not stored as a route history on our side, and are never transmitted.
• Notifications: local only. They announce phase changes and the end of a session. They are scheduled by the app on your device and involve no push server.
• Live Activity and Dynamic Island: show the current interval on the Lock Screen. The content is generated on device.

Every permission can be revoked at any time in iOS Settings (and in the Health app for health data). The app degrades gracefully: without heart rate it still runs the protocol, without location it still times the intervals.

5. Exports and external links

You can export workout history as a CSV file using the iOS share sheet. The export can contain session dates, durations, completed sets, average heart rate, cadence, and steps where available. A temporary export file is created on device. It is sent only to the app, storage location, or recipient you select, whose own privacy practices then apply.

Links to this website, research, and other external pages open the relevant destination. Visiting them is separate from using the offline workout timer.

6. This website and support emails

These app pages use local images, system fonts, and a small local script for the screenshot tour. We do not add analytics, advertising, or tracking cookies. Cloudflare Pages processes technical request data such as IP address, user agent, and URL to deliver and secure the site; security cookies may be used by the hosting provider. See the website privacy notice for hosting, international transfers, and details of the studio site. Hosting request data is handled under the provider’s applicable retention practices. Our legal basis for delivering and securing the website is our legitimate interest, Article 6(1)(f) GDPR.

If you email support, we receive your email address and the information you include. We use it to answer your request under Article 6(1)(b) or (f) GDPR, as applicable. Email providers process messages to deliver and store the correspondence. We keep support mail only as long as needed for the issue and relevant follow-up; please avoid including health data unless necessary for your question.

7. Your privacy rights

We cannot access or erase the workout history stored on your device. You can delete sessions in the app, export history from Settings, and manage Health entries in Apple Health. If you have contacted support or visited the website, personal data may be processed as described above. Where applicable, you may request access, correction, erasure, restriction, or portability, and object to processing based on legitimate interests. See the European Commission’s explanation of your rights.

To exercise your rights or ask a privacy question, write to support@bytechimera.com and we will respond within one month, subject to any extension permitted by applicable law. EU and EEA residents may also lodge a complaint with their national supervisory authority; in Poland this is the President of the Personal Data Protection Office (UODO).

We do not sell personal information or share it for cross-context behavioral advertising. We do not use your data for profiling or automated decisions that produce legal or similarly significant effects.

8. Children

ShinshuCore is not directed at children under 13 and does not send personal data to us through the app. If you believe a child has sent us personal information through support, contact us so we can address it.

9. Changes

If a future version of the app changes how data is handled, this policy is updated before that version ships, and the "last updated" date above changes with it.

10. Contact

Data controller: Przemysław Bocer, Poland. For privacy questions, requests, or suggestions about how ShinshuCore works, email support@bytechimera.com. You may also use the ShinshuCore Support page for general help.