myHHD: Privacy policy

Effective from 18 October 2026, updated 11 November 2026. The Czech version is the original; other languages are translations.

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myHHD is a diary for home haemodialysis and supplies. The app is designed so that your data stays with you. The author has no access to it and runs no server where it would be stored.

What data the app processes

The records you enter: dialysis sessions, weights, ultrafiltration, supplies, deliveries, orders and settings. Weights, ultrafiltration and dialysis records are health data.

Where the data is stored

• In the browser storage on your device.
• If you switch on sync, also in a folder named myHHD in your own Google Drive.

The data is not sent anywhere else unless you send it yourself (an order, export, PDF or backup). The app uses no analytics or advertising tools.

Photos of delivery notes are read on your device and are not sent anywhere. Contacts you enter (for example for suppliers) stay with you and are used only to send orders.

Permissions

• Google Drive: only files the app has created itself, for backups and syncing between devices. Connecting is optional; the app works fully without it, but the data is then only on the device.
• Camera and photos: the app has no access to them. For a delivery note it opens the system menu and receives only the photo you pick or take.
• Persistent storage: so the browser does not delete data when space runs low. Usually the browser decides on its own without asking.
• Clipboard and sharing: only when you tap Copy or Share yourself.
• The app does not use location, microphone, contacts or notifications.

Activity log and problem reports

To help find the cause of problems, the app keeps a log on your device of what happened in it: which screens you opened, which kinds of records were created (without values), sync progress and errors. The log contains no weights, ultrafiltration, quantities, material names, notes or contacts, but it does contain the times of use. It is kept for 14 days, is not synchronised and is never sent by itself. You can switch it off and delete it in Settings > Report a problem.

Only you can attach it to a problem report, by an explicit choice, and you can view it first. An attached log is used solely to find and fix the problem.

What the author receives

The only personal data the author receives is what you email yourself: your email address, the message, the app version and device, and optionally the attached activity log. Please do not send health data, backups or values; if they arrive anyway, the author deletes them.

• Controller: Tomáš Kosina, contact@myhhd.app.
• Purpose: replying to your message, finding and fixing problems.
• Legal basis: legitimate interest in handling a message you sent yourself (Art. 6(1)(f) GDPR).
• Retention: while the app is developed and run, because older reports help with recurring problems. On your request the message is deleted earlier. An attached activity log is deleted once the problem is fixed.
• Recipients: no one, except the email providers (forwarding by Cloudflare, mailbox by Google Gmail).

You have the right to access, correct and delete this data and the right to object. Just write to contact@myhhd.app. You can lodge a complaint with the Czech Office for Personal Data Protection (uoou.gov.cz) or with the data protection authority in your country.

Access to Google Drive

The app requests only the drive.file permission. It therefore sees only the files it has created itself, not the rest of your Drive. It uses data from Google Drive solely to sync and back up your own records between your devices. It does not share the data with anyone, does not use it for advertising or to train artificial intelligence models, and nobody reads it.

Use of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements.

You can revoke access at any time in your Google Account settings (Security > Third-party apps). The data in the myHHD folder on your Drive stays there and you can delete it yourself.

Signing in to Google

So that sync works without signing in again and again, Google issues the app a long-term permission. It stays only on your device. To renew access (roughly once an hour) the app sends it to a small function on Cloudflare, which exchanges it with Google for new access and returns it. The function stores nothing and your records never pass through it; the app sends them directly to Google Drive.

Hosting

The app's files are delivered by Cloudflare. When a page loads, Cloudflare routinely processes technical data such as the IP address for its operation and security. Health data does not pass through Cloudflare.

Medical device

The app is for record keeping. It does not replace your doctor's instructions and does not recommend treatment settings. The stock forecast and suggested order are based on your rules and stock counts; check the order before sending it.

Contact

Tomáš Kosina, contact@myhhd.app