Privacy Policy

Privacy Policy

Version 1.6.0. Effective September 29, 2026. Last updated September 29, 2026.

1. Who we are

Zuyu is published by Nb41 Labs LLC ("Nb41 Labs", "we", "us"), an independent software company in Sheridan, Wyoming, United States. This policy explains how the Zuyu mobile app handles information, and section 16 explains the limited aggregate measurement of the getzuyu.com website. You can reach us at contact@getzuyu.com.

2. Scope

This policy covers the Zuyu mobile app, and section 16 covers the public getzuyu.com website. It does not cover other companies or services, including the app stores that distribute Zuyu or any other website you reach by following a link. Zuyu is offered in the United States.

3. How Zuyu handles your information

Zuyu is a local-first app. The information you enter is stored on your device. Zuyu does not require an account, does not sign you in, and does not sync your health entries to a server operated by Nb41 Labs. There is no Zuyu cloud account for your records.

The information you enter leaves your device only when you take an action that sends it, such as exporting a report, sharing or printing a file, or creating a backup file. You control those actions. Two services receive technical and purchase information on their own, described in sections 7 and 8; it never includes your entries.

4. Information the app handles on your device

Depending on how you use Zuyu, the app stores entries such as:

• Medications you add, including names, forms, schedules, and dose information you enter.
• Doses you log and dose changes you record.
• Symptoms and daily check-in notes, including a note that you felt fine.
• Supply and refill details you enter, such as remaining amount, refill date, and refill threshold.
• Weight values you choose to record for appointment context.
• Reminders and schedule settings.
• Appointment-preparation and report content generated from your own entries.
• App settings, including privacy and app-lock preferences.

These entries are kept on the device as you wrote them. Zuyu does not convert, diagnose, or interpret them as clinical facts.

Some views combine your entries into a figure, such as a low-supply status, a count of days until a refill date you entered, or a count of scheduled medication days before a visit. These figures are produced on your device from what you entered. They are not sent anywhere.

5. What Nb41 Labs does and does not receive

Nb41 Labs does not receive your health entries. Specifically:

• Zuyu does not transmit your medications, doses, symptoms, notes, weight, supply figures, or any other health entry to Nb41 Labs.
• Zuyu contains no advertising software, no tracking software, and no attribution software.
• Zuyu does not sell personal information and does not share personal information for targeted advertising.
• Zuyu does not connect to Apple Health or Android Health Connect.
• Zuyu does not request access to your camera, photo library, contacts, calendar, or location. Zuyu asks for the microphone only for voice check-in, which is described in section 6.

If you email us for support, we receive what you choose to put in that message. Please do not include sensitive medical details when you write to us.

Two services receive limited information that is not a health entry, and each is described in full below: Sentry receives technical crash diagnostics, in section 7, and RevenueCat receives subscription information and the device details listed in section 8. Neither receives your health entries.

6. Voice check-in, the microphone, and speech recognition

You can write a check-in by typing, which is always available, or you can speak it. Speaking is optional, and nothing in Zuyu requires you to use it.

Zuyu asks for microphone permission only when you start a voice check-in. It does not ask at launch, and it does not ask if you never use the feature. You can decline, and you can withdraw the permission later in your device settings; typing continues to work either way.

When you speak a check-in, your device's own speech recognition turns what you said into text on the device. Zuyu requires on-device recognition and does not fall back to a network recognizer: if your device cannot recognize speech on the device, Zuyu tells you and declines to listen rather than sending your voice somewhere else.

Zuyu never asks the recognizer to save a recording, so no audio file is written. Zuyu receives the text and nothing else. No audio and no transcript is sent to Nb41 Labs, to Sentry, or to any other service. The recognized text is used to fill in the check-in for you to review, and it is not kept: it exists only while you are working on that check-in, and Zuyu does not write it to the database. What is saved is the check-in you confirm, the same entries you would have typed, in the same encrypted database as everything else you log.

Voice check-in is part of the paid Plus tier. Essential includes a 7-day trial of voice check-ins, after which speaking a check-in requires Plus. Typing a check-in is unlimited on every plan.

7. Crash reporting and diagnostics

Zuyu uses Sentry to identify, diagnose, and repair app crashes and technical failures. Sentry is an error-monitoring service operated by Functional Software, Inc. When Zuyu crashes or hits a technical failure, it sends a limited technical diagnostic report to Sentry over an encrypted connection.

A diagnostic report is limited to technical information about the failure itself. It may include:

• the exception type;
• a sanitized stack trace;
• the app version and build number;
• the platform, such as iOS or Android, and the operating-system version;
• the release environment;
• a coarse internal error code;
• a sanitized name for the app screen or feature area where the failure happened;
• an identifier and a timestamp for the report itself;
• its severity level;
• the name and version of the error-monitoring library that produced it.

Zuyu does not send your device model.

Sentry does not receive your health information or your identity. Specifically, a diagnostic report does not contain medication names, medication identifiers derived from what you entered, dose amounts, schedules, injection dates, symptoms, side effects, notes, weight, supply or refill values, report contents, exported information, backup contents, your files, or the contents of the app database. It does not contain your email address, your name, an account identifier, or an advertising identifier. Zuyu attaches no user record to a diagnostic report. From version 1.0.1, Zuyu rebuilds every report on your device before it is sent, so that a report keeps only the fields listed above, including a report that a crash produced before the app was running.

Sentry works out an approximate location, a country, a region, and a city, from the network address a diagnostic report arrives from. It is not precise, it contains no coordinates and no street address, and Zuyu does not send it: Sentry derives it at its end. Zuyu does not use your device location and does not ask for location permission. Zuyu's Sentry project is configured so that both the network address and that derived approximation are discarded before the report is stored, so neither is retained.

Sentry is used only to fix technical faults. It is not used for advertising, tracking, behavioral analytics, product analytics, profiling, session replay, or user-feedback collection. Zuyu contains no advertising software, no attribution software, and no product-analytics software of any kind. From version 1.0.1, no screen views, feature usage, session data, or product events are collected or transmitted.

Versions of Zuyu before 1.0.1 sent more than that with a crash report, and this is what they sent. A report carried a short trail of what happened just before the failure: moving from one screen to another, the app going to the background or returning to the foreground, and a tag naming the screen the failure happened on. On iPhone and iPad, those versions also reported when the app had stopped responding for a couple of seconds, whether or not it then crashed. None of it contained your health information or your identity. From version 1.0.1 Zuyu sends none of it: the trail is switched off, the app-responsiveness reporting is switched off, and every report is rebuilt on your device before it is sent.

Sentry processes this diagnostic information as a service provider acting for Nb41 Labs, and is required to protect it consistently with its contractual and legal obligations. Sentry's own privacy practices are described in its privacy policy.

8. Subscriptions and app-store transactions

Zuyu offers a free tier called Essential and a paid tier called Plus. Plus is sold as an auto-renewing subscription at 9.99 US dollars per month or 59.99 US dollars per year. A Premium tier is not sold.

Payment is processed by the app store on your device, which is the Apple App Store or Google Play. Nb41 Labs does not receive your full payment-card number or your bank details. Apple and Google process purchase information under their own privacy policies.

Zuyu uses RevenueCat to manage subscriptions. RevenueCat is a subscription-management service operated by RevenueCat, Inc. It records whether a subscription is active so that Plus unlocks on your device and can be restored if you reinstall the app or move to a new device. To do that, RevenueCat's software runs inside Zuyu. It checks your subscription status, and the plans on offer, when the app opens and when you come back to it, whether or not you have bought Plus.

RevenueCat's software sends RevenueCat the information below. Some of it is needed to manage a subscription; the rest, such as the device details, the software sends with its requests on its own. Depending on your device and on whether you buy Plus, it includes:

• an anonymous app user identifier, which RevenueCat's software generates the first time Zuyu opens and which can come back with a device backup or a move to a new device (Zuyu's own backup file does not carry it);
• the platform, Zuyu's identifier and version (on Apple devices, also its build number), the operating-system version, and the versions of RevenueCat's software and of the store software it uses;
• the device model (on Android, the model and its brand);
• the country of your app-store account (on Android, the Google Play billing country once billing has connected);
• your device's language settings (on Apple devices, up to three preferred languages; on Android, the device's languages and Zuyu's own);
• on Apple devices (iPhone, iPad and Apple Vision Pro), Apple's identifier for vendor, an identifier Apple assigns to each app developer's apps on your device and that is not the advertising identifier;
• on Apple devices, your App Tracking Transparency status, which can only read "not determined", "restricted", or "denied", because Zuyu never asks to track you. It is sent the first time Zuyu goes into the background or is covered by a system prompt, again whenever it changes, and with each purchase record;
• technical details of each request, such as whether the app is in the background and whether it is a test build;
• whenever a purchase is made, restored, or renewed, or is found on your store account (for example after you reinstall Zuyu): the store's record of it (on Apple devices, Apple's signed transaction or App Store receipt, with its identifiers and dates; on Android, the Google Play purchase token); the product identifier and its price, currency, period, and any introductory or promotional offer; and the offering it came from;
• on Apple devices, with each purchase record and when you tap Restore, even if you never bought anything: the App Store's signed record of your download of Zuyu, which includes when you first downloaded it, the version you first downloaded, and an identifier Apple assigns to that download. On iOS 15 the App Store receipt takes its place, and it may also be sent to check whether you can have an introductory offer.

From the store's records, RevenueCat works out the renewal status, the expiration date, any trial, and whether you have Plus. Like any internet service, RevenueCat also receives the network address each request comes from, with the standard information a device includes in any internet request. Zuyu sends RevenueCat no location. On Android, RevenueCat's software also gives Google Play a one-way scrambled form of the anonymous identifier with each purchase.

On Android, versions of Zuyu before 1.0.1 also saved the identifier in Google's Block Store once a purchase was on that copy's record, whether bought or restored from the Google account. Block Store is backed up with your Google account and keeps the identifier after Zuyu is reinstalled, so that RevenueCat could link a reinstalled copy to the earlier one. From version 1.0.1 Zuyu no longer does this, and it cannot remove what an earlier version saved there.

RevenueCat does not receive your health information. It does not receive medication information, dose information, symptoms, notes, weight, supply information, reports, exports, backups, or any user-entered health history. Until a purchase or a restore is recorded, or on iOS 15 an introductory-offer check sends the App Store receipt, RevenueCat knows your copy of Zuyu only by the anonymous identifier described above and, on Apple devices, by Apple's identifier for vendor. The store's records then add identifiers that are the same on each device where you use the same store account. Zuyu does not send RevenueCat your name, your email address, or an account identifier, and there is no Zuyu account to send.

RevenueCat is not used for advertising or behavioral tracking. It processes subscription information as a service provider acting for Nb41 Labs, and is required to protect it consistently with its contractual and legal obligations.

You manage, renew, and cancel a subscription through your app-store account.

9. Export, sharing, printing, and backup

Zuyu lets you export a raw copy of your data, share or print reports you generate, and create a backup file you can use to restore your data later.

When you export, share, or print, the resulting file goes wherever you send it, using your device and the apps you choose. Anyone you share a file with can read what it contains, so review it first.

A backup is a file you create and control. If you set a recovery password when you create it, the backup file is encrypted. If you do not set one, the backup file is not encrypted, so store it somewhere you control. If you save a backup or an export to a cloud service, a messaging app, or another device, that copy is subject to the settings and protections of wherever you put it, and it is no longer governed by this policy.

10. Device backups and cloud services

Zuyu does not use iCloud Drive, CloudKit, iCloud key-value storage, or any other cloud service to store or synchronize your entries. Zuyu uploads none of your entries.

Your device makes its own backups, separately from Zuyu. On iPhone and iPad, the backup your device creates, whether to iCloud or to a computer, may include Zuyu app data along with data from your other apps. That backup is created, encrypted, and controlled by Apple and by your device settings, not by Zuyu. You can review and change what your device backs up in your device settings. On Android, Zuyu's health database is excluded from Google's automatic app backup.

11. Retention and deletion

Because your entries are stored on your device, they remain until you delete them in the app or remove the app. Deleting the app removes your entries and the encrypted database that holds them. On iPhone and iPad, one item is left behind: the key to that database, which Apple keeps in the system keychain and does not remove when an app is deleted. It unlocks nothing once the database is gone, and installing Zuyu again does not bring any entry back. If you would rather not leave it there, use Delete all data inside the app before you delete the app: that deletes the key too, and tells you if it could not.

Backups, exports, and shared files you saved elsewhere are not removed when you delete the app. You control those copies, and a copy held in a device backup follows your device backup settings. If you email us, we keep that message as long as needed to respond and to maintain ordinary business records.

Asking us to delete what the two services hold. Your health entries are on your device, so there is nothing for us to delete there. The two services described in sections 7 and 8 are different: Sentry may hold a technical crash report, and RevenueCat holds a record for each copy of Zuyu that has opened, under the anonymous identifier described in section 8. You can ask us to delete either of those. Write to contact@getzuyu.com, by using Support inside the app or directly, and tell us what you want removed. We will action it and confirm. Because there is no account, we cannot look you up by name. For a purchase, include the store receipt or transaction identifier, so that we remove the right record and not someone else's. Zuyu does not show RevenueCat's anonymous identifier, so for a copy of Zuyu with no purchase on record we cannot tell which record is yours, even if Restore was tapped on an Apple device. That record holds the identifier and the details described in section 8, and no name or email address, because Zuyu never sends them.

12. HIPAA and this app

The Health Insurance Portability and Accountability Act, known as HIPAA, applies to healthcare providers, health plans, healthcare clearinghouses, and their business associates. Nb41 Labs is none of those things, and publishing Zuyu does not make it one.

Health-related information you enter into a consumer app is not automatically protected health information under HIPAA. Nb41 Labs does not claim to be HIPAA compliant, and this policy should not be read as a HIPAA notice. How your information is handled in Zuyu is governed by this Privacy Policy and by applicable consumer-protection and privacy law. Because Zuyu keeps your entries on your device and does not send them to us, the practical protection for your records comes from your device and from the choices you make about exporting and sharing.

13. Age requirement

Zuyu is intended for adults who are 18 years of age or older. Zuyu is not directed to children, and we do not knowingly collect information from anyone under 18. Because Zuyu does not require an account and keeps entries on the device, it does not build a profile of any user.

14. Security and its limits

Zuyu stores your data locally using device-level protections. App data is held in an encrypted on-device database, and the key for that database is held in your device's secure store. If encryption cannot be established, Zuyu stops rather than storing your records unprotected.

Zuyu also offers optional on-device protections: a lock that requires the Face ID, fingerprint, or passcode already set up on your device before the app opens, and an option to hide your content in the system app switcher. Your device performs that check and returns only whether it succeeded. Zuyu does not create its own PIN, does not receive or store your passcode, and does not receive or store your biometric data.

No security is perfect, and we do not promise that any system is impenetrable. Keeping your device locked, updated, and under your control is an important part of protecting your information.

15. Where processing happens

Zuyu is offered in the United States, and the limited processing described above takes place in the United States.

16. The getzuyu.com website

This section is about the public website at getzuyu.com. It is not about the Zuyu app. Nothing described here touches the health information the app keeps on your device.

The company that hosts getzuyu.com writes an ordinary server log entry for each request a browser makes, as web servers do. An entry records the page or file requested, the date and time, the response status and size, the address of the page that linked to the request if there was one, and the description a browser gives of itself. The hosting provider shortens the visitor network address before it is written, so a complete address is never recorded in the log we can read.

We read those logs in aggregate to understand how the website is being used: how many pages were viewed, which pages people arrived on, which sites referred them, and how many times a store button was used. What we keep is daily totals. The host retains its own log files only for a limited period, and we do not keep a copy of them. We do not build a profile of you, and we do not attempt to recognize you between visits or across devices.

The website sets no analytics cookie, carries no advertising or tracking software, creates no persistent visitor identifier for measurement, does not use fingerprinting, and does not record your screen or what you type. Website measurement is never joined to the health information Zuyu holds in the app. That is not something we could do even if we wanted to, because those entries never leave your device.

When a verified store listing is public, its button on this website points to a getzuyu.com address, such as getzuyu.com/go/android, that immediately forwards your browser to that official listing. The forwarding runs no script and sets no cookie. Like any other request, it is written to the server log described above, and we count those requests in aggregate, as daily totals, to learn how many visits lead to a store listing. We cannot see whether you install Zuyu after reaching the store, and we do not try to.

The website does not add campaign codes, cookies, or identifiers to store links. Your health and check-in entries remain on your device.

17. Changes to this policy

We may update this policy. When we do, we will change the version and the dates at the top of this page. Continued use of Zuyu after an update means the updated policy applies.

18. Contact

Nb41 Labs LLC
30 N Gould St Ste N
Sheridan, WY 82801
United States
contact@getzuyu.com