LEGAL

Privacy Policy

Last updated: 8 October 2026

Ischys is an on-device workout tracker for iPhone and Android. This policy explains what the app does with your information. It applies to the Ischys app and this website (ischys.app).

What we collect

Nothing. Ischys has no backend, no user accounts, and no telemetry. Everything you enter — workouts, sets, weights, reps, notes, routines, and personal records — is stored in a database on your device only. We never receive it, and we have no ability to see it.

Apple Health (HealthKit) — iPhone

On iPhone, if you choose to connect Apple Health, and only with your explicit permission, Ischys:

• Reads your heart rate while a workout is recording (for example, from an Apple Watch) to show your live heart rate during the session.
• Writes your finished workouts to Apple Health, so they appear alongside the rest of your activity.

This health and fitness data stays on your device and within Apple Health. Ischys does not transmit it off the device, does not share it with any third party, and does not use it for advertising, marketing, or data-mining of any kind. You can revoke Health access at any time in the iOS Settings app under Privacy & Security → Health.

Apple Watch — iPhone

The optional Apple Watch companion mirrors and controls a live workout. It communicates only with the Ischys app on your paired iPhone over Apple's on-device connectivity. No workout data leaves your devices.

Health Connect — Android

On Android, if you choose to connect Health Connect, and only for the data types you allow, Ischys:

• Writes your finished workouts as strength-training exercise sessions, with their active calories when known, so they appear alongside the rest of your activity. Editing a workout in Ischys updates the entry Ischys wrote.
• Reads heart rate and active calories recorded during a workout by another device or app, to show that workout's average and maximum heart rate and its energy. The average and maximum are stored with the workout in the database on your device.
• Reads your latest weight, when you choose to fill in your bodyweight from Health Connect, and your body fat for your measurement history.

This health and fitness data stays on your device and within Health Connect. Ischys does not transmit it off the device, does not share it with any third party, and does not use it for advertising, marketing, or data-mining of any kind. Ischys's use of information received from Health Connect adheres to the Health Connect Permissions policy, including the Limited Use requirements. You can change or revoke access at any time in Health Connect under App permissions.

Android permissions

Apart from Health Connect, the Android app asks for these permissions, each only when the feature needs it:

• Notifications, to show your workout in progress and to alert you when a rest timer ends. Both are created on your device; no push service is involved.
• Alarms & reminders, so that alert arrives on time rather than when Android next gets round to it.
• Saving to your gallery, only when you choose to save a workout summary as an image. Ischys adds that one image and cannot read your photos.

None of these send anything off your device.

Where your data lives, and backups

Your training log is a local database on your phone. It is included in your device's normal backup if you have that enabled — iCloud Backup on iPhone, Google's device backup on Android. Those backups are managed entirely by Apple or Google under their own terms — Ischys has no access to them.

Exporting your data

You can export a full copy of your data as a JSON or CSV file at any time. Once you export or share a file, what happens to it is up to you; it leaves Ischys's control the moment you choose to send it somewhere.

Third parties and tracking

Ischys contains no analytics SDKs, no advertising, no trackers, and no third-party data collection. The bundled exercise catalogue comes from the public-domain free-exercise-db and ships inside the app; loading it involves no network request.

This website is a static page hosted on Cloudflare Pages. Cloudflare may process standard server logs (such as IP addresses) to deliver and protect the site, as described in Cloudflare's privacy policy. The site sets no cookies and runs no analytics.

Children

Ischys is not directed at children and collects no personal information from anyone, regardless of age.

Open source

Ischys is open source under the MIT licence. You don't have to take "nothing leaves your device" on faith — you can read exactly what the app does at github.com/ischys-app/Ischys.

Changes to this policy

If this policy changes, the "Last updated" date above will change with it, and the current version will always be at this URL.

Contact

Questions about privacy? Open an issue at github.com/ischys-app/Ischys/issues.