Privacy Policy

Last updated: 3 September 2026 · LiftDiff for iOS

The short version. Everything you record stays on your device. There is no analytics and no third-party tracking. If you turn on iCloud sync, your records go to your own private iCloud database, which the developer cannot read. Only if you turn on Friends does a summary of each workout become visible, through iCloud, to friends you have accepted. Even then, the records themselves — your sets, weights and notes — never leave your device.

1. Who this covers

This policy applies to the iOS application LiftDiff, provided by Yoshiaki Nozaki. Questions go to supportliftdiff.com.

2. What is stored on your device

All of the following is written to the app's own storage area on your device (Documents/liftdiff.sqlite and the system preferences store):

Your name, if you enter one (display only)
Your body weight, used to calculate load for bodyweight exercises
Training records: exercises, weight, reps, RIR/RPE, dates, and notes
Routines and folders
Training settings: goal, experience, frequency, session length, equipment, focus areas
App settings: language, theme, units, first day of week

The developer has no access to any of it.

3. What is not collected

No advertising identifier and no device identifier are read
No analytics SDK and no advertising SDK are embedded
The only network calls are to iCloud, for sync and for Friends. Both are off unless you turn them on
Your training records are never sent to the developer (for what Friends handles, see 5)

4. iCloud sync (optional)

If you turn on sync, your records are copied to the private database of your own iCloud account, in a container reserved for this app. Apple operates that storage on your behalf under Apple's privacy policy. The developer cannot read a private database. Turning sync off stops further copies; removing the data is done from your iCloud settings or by deleting the app.

5. Friends (optional)

Friends is off by default, and nothing is transmitted until you turn it on in Settings. Once on, the following is placed in your own iCloud and shared so that only friends you have accepted can read it.

A summary of each workout — date, duration, set count and how the load was split across muscles. Exercise names and weights are included only if you choose to include them. Individual sets, notes and your bodyweight are not. Summaries expire after 30 days
Your profile — display name, icon (emoji and colour), lifetime workouts, time and sets, friend count, and which days you trained over the last three months
Your best per exercise — estimated 1RM, top weight and reps, and sets this week, used for the rankings (if you do not include weights, only the set count)
Reactions — which emoji you put on which post

Your friend code (six characters) and any friend requests are held in a public CloudKit database, because that is what makes connecting possible. It contains only the code, your CloudKit identifier and your display name. That part is in a place the developer can also query. If you report a post, the report — its reason, its target and the identifier of the person reporting — is stored there too, and the developer reads it. Reports are used for moderation only, and the other person is not told.

If you choose to be notified about friends’ workouts or reactions, CloudKit subscriptions use Apple’s push notification service. Those notifications travel through Apple; no server of the developer’s is involved.

Blocking hides both sides’ posts and rankings from each other, and the other person is not notified. Removing a friend stops any further sharing with them. “Stop sharing with friends” in Settings deletes the summaries, reactions, friendships and friend code you have created. The records on your device are untouched.

6. Device features the app uses

Photos (add only) — used only when you save a share image. The app never reads your photo library.
Local notifications — used only to tell you a rest timer finished. Notifications are assembled on the device and are not sent anywhere.
Live Activities — used to show the rest timer on the Lock Screen and Dynamic Island. This runs entirely on the device; no push tokens are used.

7. Information you choose to send elsewhere

Exporting your history as JSON or CSV, copying it to the clipboard, saving a share image, or posting one to social media are all actions you take. Once the data leaves the app this way, it is governed by wherever you sent it, not by this policy.

8. Third parties

Your information is not sold, shared, or handed to any third party. The app bundles one open-source component, MuscleMap (MIT licence), which draws the body diagram and performs no networking.

9. Backups

Your records may be included in your own device backup (iCloud Backup or a computer backup). That backup belongs to you; the developer has no access to it.

10. Retention and deletion

Your records stay on the device until you delete them
Individual workouts can be deleted from the history screen
Settings has an option to erase all records, which asks twice and offers a JSON backup first
Deleting the app removes everything stored on the device

Deleting the app cannot be undone. Export your history first if you might want it later — the export is deliberately in open formats so it will outlive the app.

11. Getting your data out

Profile → Import / Export writes your full history as JSON or CSV, or copies it to the clipboard. The formats are published: history and routines.

12. Your rights

Because the developer holds none of your information, requests to access, correct, or delete it are answered by your own device — the data is already in your hands. If you have a question anyway, write to supportliftdiff.com.

13. Children

LiftDiff is not intended for children under 13, and is not directed at them.

14. If you are outside Japan

Under the GDPR and UK GDPR, the developer does not act as a controller of your personal data, because none is collected. Under the CCPA, no personal information is sold or shared. Where you enable iCloud sync, Apple processes that data as your provider.

15. Changes

If this policy changes, the date at the top changes with it, and material changes are announced in the app.

16. Contact

supportliftdiff.com