Steadyhand Privacy Policy
Last updated: June 28, 2026
- Steadyhand works fully without an account. Your practice is saved on your device.
- Nothing leaves your device unless you create an account (to sync) or choose to share a report.
- We do not sell your data, show ads, or use third-party tracking or analytics.
- You can export or permanently delete all of your data at any time from within the app.
This policy explains what information the Steadyhand mobile app (“Steadyhand”, “the app”, “we”) collects, how it is used, and the choices you have. Steadyhand is a hand-steadiness and tremor practice tool designed to be private by default.
Local-first by design
Steadyhand is a “local-first” app. When you use it without an account, all of your practice data — your exercise sessions, the measurements they produce, and your progress over time — is stored only on your device. It is not sent to us or anyone else.
Information we collect
Practice data (stored on your device). When you complete an exercise, the app records measurements such as timing, steadiness and rhythm metrics, the exercise type and difficulty, and basic device characteristics (device model, screen size and pixel density, and the app version) used to calibrate and display your results. A detailed “raw” capture trace of your finger movement may also be recorded on your device to power your own data export — this raw trace never leaves your device and is never uploaded.
Account information (only if you choose to create an account). If you sign up to sync across devices or to share reports, we collect your email address and an authentication credential. You may sign in with an email and password, with Sign in with Apple, or with Google; when you use Apple or Google, we receive your email address (and name, if you allow it) from that provider to create your account. Authentication is handled by our cloud provider, Supabase.
Profile details (optional). You may add a display name and birth year. These are used only to label the summary report you choose to share with a clinician.
Synced practice data (only if you are signed in). If you have an account, your sessions, exercise measurements, and daily progress summaries are synced to your private cloud space so they are available across your devices. The on-device raw capture trace described above is excluded from this sync.
What we do not collect. We do not collect precise location, contacts, your microphone or camera input, advertising identifiers, or browsing activity. Steadyhand contains no advertising and no third-party analytics or tracking software.
How we use information
- To run the exercises and show your measurements and progress.
- To sync your data across your own devices when you are signed in.
- To generate a report you can choose to export or share with a clinician.
- To respond to you if you contact support.
We do not use your data for advertising, profiling, or any form of automated decision-making, and we do not sell or rent your personal information.
How your information is stored and shared
On your device. Local data is stored in the app’s on-device storage. If you sign in, your session tokens are kept in your device’s secure keychain.
In the cloud (only if signed in). Synced data is stored with Supabase, our cloud hosting and authentication provider, acting on our behalf. Access is restricted by row-level security so that your data is only ever accessible to your own account. Data is transmitted over encrypted connections (HTTPS).
Sharing you initiate. Reports (PDF) and full data exports (JSON) are created only when you ask for them, and are shared only through the destination you pick (for example, your own email or files app). We are not a party to that sharing.
Service providers. We rely on Supabase (cloud storage and authentication) and, if you choose those sign-in methods, Apple and Google (authentication only). We do not share your data with any other third parties, and we never sell it.
Data retention and deletion
Local data remains on your device until you delete it or remove the app. If you have an account, synced data is retained until you delete it. You can permanently delete everything — your on-device data and, if you have an account, your cloud account and all its data — at any time using Settings → Delete all my data in the app. This is a hard deletion and cannot be undone.
Security
We use industry-standard measures to protect your information, including encrypted data transmission, secure on-device credential storage, and per-account access controls (row-level security) on the cloud. No method of storage or transmission is completely secure, but we work to protect your information and limit what is collected in the first place.
Children’s privacy
Steadyhand is not directed to children under 13 (or the minimum age required in your country), and we do not knowingly collect personal information from them. If you believe a child has provided us personal information, please contact us and we will delete it.
Your choices and rights
Because the app is usable without an account, you can choose to keep all of your data on-device only. You can export your data (JSON) at any time, and you can delete all of your data and your account from within the app. Depending on where you live, you may have additional rights to access, correct, or delete your personal information; contact us and we will help.
Notifications
If you turn on practice reminders, they are scheduled locally on your device. We do not operate a push-notification server and do not use reminders to collect data.
International users
If you create an account, your data may be processed and stored on servers operated by our cloud provider, which may be located in a country other than your own. By creating an account you consent to this processing.
Changes to this policy
We may update this policy from time to time. When we make material changes, we will update the “Last updated” date above and, where appropriate, ask you to review the changes in the app.
Contact us
Questions about this policy or your data? Email abelchen919@gmail.com.