Privacy Policy — Rebuild

Last updated: 26 August 2026

Rebuild is an exercise-habit app for people with back pain. This policy describes exactly what the app collects, why, and what you can do about it. It is written to match what the code actually does.

The short version

You can use Rebuild without an account. Nothing leaves your phone until you sign in.
Signing in with Apple adds the community board. From then on, your name, photo, condition line, workout history and anything you write are stored on our server so the board can show them.
Motion data never leaves your phone. Rep detection runs entirely on the device; only the result (a session, its reps and points) is saved.
We do not track you, run ads, or sell data. There are no analytics SDKs and no third-party trackers in the app.
You can delete your account and all its data from inside the app at any time: Me → gear → Delete account.

What we collect, and when

Your profile, sessions, points, streak, weekly check-ins and journal entries are stored locally on your iPhone. We cannot see them.

Sign in with Apple gives us a unique user identifier and, if you allow it, your name and email address (which may be Apple’s private relay address). We store:

Data	Why
Name	Shown next to you on the community board
Email address	Identifies your account; shown to you in Settings
Profile photo (optional)	Shown next to you on the board
Your “line” (e.g. “Can’t tie my shoes”)	Shown on the board so people with similar problems recognise each other
Workout history — day, exercises, reps, sets, points	Your progress, and your position on the weekly board
Weekly check-ins (better / same / worse)	Your progress trend, shared on the board
Anything you write in a note or journal entry	Shown on the board to other signed-in members

When you sign in for the first time, history already stored on your phone is uploaded so it isn’t lost. If you sign in on a device with no history, your account’s history is downloaded to it.

If you report or block someone

Reports. When you report content, we store your account identifier, who and what you reported, the reason you chose, and when. Reports exist only so we can review them — they are never visible to other members, and the person you reported is not told who reported them.
Blocks. When you block someone, we store the pair (you → them) so the server can keep you off each other’s board and feed. The blocked person is not notified.

What we do not collect

Motion and accelerometer data. Used only in memory, on your device, while a session is running.
Location, contacts, health records, HealthKit data, or advertising identifiers. The app requests none of these.
Analytics or crash-reporting data. The app contains no such SDK.

Who can see your data

Other signed-in members see your name, photo, line, weekly and lifetime points, days active, weekly check-in result, and any notes or journal entries you write. Treat anything you write as public to the community.
Nobody else. We do not share, sell or rent data to third parties, and we do not use it for advertising.

Where it is stored

On Supabase (PostgreSQL and object storage) in the Asia-Pacific (Tokyo) region, behind row-level security: your rows are readable and writable only by your account, and the community board is served by restricted server-side functions that expose only the fields listed above.

Data is encrypted in transit (HTTPS) and at rest by the hosting provider.

Retention and deletion

We keep your data until you delete it. Me → gear → Delete account removes your account, your profile, your check-ins, your notes, your photo, and any reports or blocks you made from the server, and wipes the app’s local data on that device. This is immediate and cannot be undone.

Signing out (without deleting) leaves your account data on the server so you can sign back in later.

Your rights

Depending on where you live, you may have rights to access, correct, export or delete your personal data, and to object to processing. Account deletion in the app covers deletion. For anything else, contact us at the address below and we will respond within 30 days.

Children

Rebuild is not directed at children under 13, and we do not knowingly collect data from them.

Medical disclaimer

Rebuild is not a medical device and does not provide medical advice, diagnosis or treatment. It is an exercise-habit tool. Always consult a qualified clinician about back pain, especially with any of the red flags the app lists during onboarding.

Changes

If this policy changes materially, we will update the date above and note the change in the app’s release notes.

Contact

Email: mamingming@gmail.com