Your training stays yours.

Ferron has no account, no ads and no tracking. I don't collect, receive or sell any of your data, and your health data is used only to show you your own training.

Effective 10 November 2026

Below I explain what that means in practice: what stays on your device, what Ferron reads from and saves to Apple Health, what goes to your iCloud, and which permissions the app asks for. This policy covers Ferron for iPhone, iPad and Apple Watch, along with its widgets and Live Activities.

Who is responsible

Ferron is made by IV Koroni, an independent developer in Sweden. IV Koroni is the data controller for this policy. You can reach me at ivkoroni@gmail.com.

What I collect

Nothing. Ferron has no backend, and it never sends me your workouts, health data, location, settings or device details. I can't see what you train, how you run or what you save.

The only time I get anything about you is when you email me. If you write from Settings › Support in the app, the email already contains a short diagnostics section so I can help faster: the app version, your device model and iOS version, whether you subscribe, whether Apple Health is connected, your fitness level and units, how many workouts, runs and timers you've recorded, and a few app settings. It contains no workout details, health data or location. You can read it, change it or delete it before you send. See Contacting me.

What stays on your device

Ferron keeps these things on your device so the app is just how you left it:

• your profile: name, an optional photo, fitness level, working kettlebell weight, body weight, weekly goals and units
• your workouts, with the exercises, weights and reps, and the programs you follow and finish
• your runs, including the route of outdoor runs, your skipping sessions and your timer sessions
• heart rate and calories for each session, from your Apple Watch through Apple Health or from a Bluetooth heart rate strap, and how you chose to track it
• the workouts, programs and timers you create, your favorites and your trophies
• your settings, workout reminders, workout tracking choice and the name of your heart rate strap
• whether your subscription or free trial is active on your Apple Account

The widgets and Live Activities show today's training, your streak, your distance and steps, and the workout or timer that's running, using this same data. Your Apple Watch gets the current workout and today's summary straight from your iPhone, over Apple's own connection between your devices.

You can delete this data whenever you like: delete single sessions from your history, use Settings › Profile › Clear All History, or delete the app to remove everything from your device.

Apple Health

Connecting Apple Health is optional, and you choose exactly what Ferron may read and save in the permission screen. You can change that at any time in the Health app: tap your profile picture, then Apps › Ferron.

What Ferron reads, and why:

• workouts, heart rate and active energy, to show the heart rate and calories of your sessions
• resting heart rate, heart rate variability and cardio fitness (VO₂ max), to show how your fitness and recovery change over time. Resting heart rate and cardio fitness also make the calorie estimate and your heart rate zones more accurate.
• steps and walking and running distance, for your daily activity and the widgets
• body weight, date of birth and sex, to estimate calories from your heart rate when no Apple Watch measured them, and to work out your heart rate zones. Ferron uses your age, not your date of birth, and reads these from Health when it needs them rather than keeping a copy.

What Ferron saves: when you train with your Apple Watch, the watch saves the workout to Health, with your heart rate and active energy, so it counts toward your Activity rings. When you train with a heart rate strap instead, your iPhone saves the workout when it finishes, with the strap's heart rate, the active energy, and for runs the distance and the route. For a session with neither, you can add it to Health yourself from its page. Timer sessions aren't saved to Health. Ferron only changes or removes its own workouts in Health: it updates one your iPhone saved when you correct a run's distance, and removes a workout when you delete that session in Ferron.

Health data is used only to show you your own training inside Ferron. It's never used for advertising or marketing, never sold or shared with anyone, and never stored in iCloud by Ferron.

Apple Watch

During a workout the Ferron watch app runs a workout session, which lets your watch measure your heart rate and calories. For skipping, it also counts your jumps from the watch's motion sensors. This happens on the watch, and the results go to your iPhone over Apple's connection between your devices and, for the workout itself, into Apple Health. When you track a workout with a heart rate strap, Ferron doesn't start on your watch at all.

Location

Ferron asks for your location only while using the app, and uses it only while you record an outdoor run, to measure distance and pace and draw your route. If you lock your phone during a run, tracking carries on and iOS shows a blue location indicator. The route is saved on your device with the run. Maps are drawn with Apple Maps, which receives the map area being shown, under Apple's privacy policy. Ferron never tracks your location at any other time, and never asks for access at all times.

Bluetooth

If you pair a Bluetooth heart rate strap or connect a Bluetooth treadmill, Ferron reads your heart rate and the strap's battery level, or the treadmill's speed, incline and distance, during your session. These readings are saved with your workout on your device and, for a workout tracked with the strap, in Apple Health as described above. Ferron remembers the strap's name so it can reconnect: while the app is open it connects to your strap by itself when you put it on, so it's ready when a workout starts, and lets go of it shortly after you take it off or leave the app.

iCloud backup and backup files

If you subscribe and use iCloud Backup (Settings › Profile › Backup), Ferron saves one backup file of your workouts, programs, profile and settings in your iCloud Drive, in a space set aside for Ferron that you can't see in the Files app. Apple looks after it under the Apple Privacy Policy, and I can't access it.

To protect your health data, the iCloud backup leaves out heart rate, calories and body weight. After you restore it, Ferron reads heart rate and calories back from Apple Health for the workouts your watch recorded.

You can turn automatic backup off at any time, and Delete iCloud Backup in the same screen removes the backup from iCloud. Clear All History also clears your history from the iCloud backup.

If you export a backup file yourself, it contains everything, including heart rate, calories and body weight, so you have a complete copy. That file is yours to keep wherever you like. Ferron doesn't upload it anywhere.

Services the app connects to

Ferron talks only to Apple's own services, and you can train without any connection. It doesn't send any of them an identifier for you, and none of them pass your data to me.

Permissions

• Apple Health: asked for when you connect it. You choose each type of data separately.
• Location: asked for when you first set up an outdoor run, and only while using the app.
• Bluetooth: asked for when you first look for a heart rate strap or a treadmill.
• Notifications: asked for only if you turn on workout reminders. Reminders are scheduled on your device.
• Photos: never asked for. If you choose a profile photo, iOS gives Ferron only the photo you pick.
• Camera and microphone: never asked for.
• Tracking (App Tracking Transparency): never asked for, because Ferron doesn't track you.

You can change any of these at any time in your device's Settings.

Keeping and deleting your data

Ferron keeps your data until you delete it. Delete a single session from your history, everything at once with Clear All History, your iCloud backup with Delete iCloud Backup, and all the rest by deleting the app. Workouts saved to Apple Health, by your watch or your iPhone, stay in Health until you delete them there or in Ferron.

Children

Ferron is made for adults and older teenagers who train, and it isn't aimed at children. It doesn't collect personal data from anyone, children included.

Your rights

If you live in the EU, the EEA or the UK, the GDPR gives you the right to see, correct or delete your personal data, to limit or object to how it's used, and to take it with you. Because Ferron doesn't send your data to me, nearly everything about you is already in your own hands, on your device, in Apple Health and in your iCloud, where you can view, export or delete it.

For anything you've sent me by email, just write to me and I'll answer within one month. You also have the right to complain to a data protection authority. In Sweden that's the Swedish Authority for Privacy Protection (IMY). Elsewhere, it's the authority where you live. People in California and other places with similar laws have the same kinds of rights. Ferron doesn't sell or share personal information.

Contacting me

If you email me, I use your address, your message and any diagnostics you include only to answer you. I do this because I have a legitimate interest in replying to people who write to me. My email is handled by Google, my email provider. I keep our conversation only as long as it helps me help you, and you can ask me to delete it at any time.

This website

This website is hosted by Cloudflare. To deliver the pages and protect the site from attacks, Cloudflare processes technical details of each visit, such as your IP address, browser and the page you asked for, under the Cloudflare Privacy Policy. I don't add cookies, analytics or tracking of any kind to this website, and I don't receive information about you as a visitor.

Changes to this policy

If Ferron ever changes how it handles data, I'll update this page first and put a new effective date at the top. I'll also mention any big changes in the app's release notes.