Last updated: October 11, 2026
This Privacy Policy explains how BioRhythm: Wellness Tracker (“BioRhythm”, “the app”) handles information when you use the application.
BioRhythm is developed and provided by Express Buy OÜ, Estonia.
BioRhythm is an Android wellness journal designed to help users record daily habits, lifestyle factors, sleep, mood, energy, stress, symptoms, and other wellbeing-related observations.
The app provides personal insights, historical comparisons, and hypothetical What-if scenarios based on information entered by the user.
BioRhythm is designed to operate primarily offline, with personal journal information stored locally on the user's device. The app does not require registration or a BioRhythm user account.
BioRhythm is intended for personal wellbeing tracking and informational purposes. It is not a medical device and does not provide medical diagnoses, treatment recommendations, or clinically validated predictions.
BioRhythm may process and store information entered by the user, including:
sleep and wake times, time in bed, sleep quality, and night awakenings;
mood, energy, stress, and anxiety observations;
headaches, pain, symptoms, severity ratings, and related notes;
caffeine, alcohol, food, and other lifestyle factors;
physical activity, walking, duration, and intensity;
dates, times, and descriptions of journal entries;
user-entered profile information and preferences;
personal notes and historical observations;
analysis settings, selected categories, and What-if scenarios;
locally created backup, restore, CSV, and PDF export data;
subscription status and purchase information necessary to provide Premium functionality.
Some of this information may be considered sensitive health-related or personal wellbeing information.
The information is used to provide the journal, analytics, visualization, backup, export, and subscription features requested by the user.
Personal journal entries and wellbeing observations are stored locally on the user's Android device.
BioRhythm uses this information to display historical trends, calculate descriptive statistics, identify possible associations between recorded factors and outcomes, and support hypothetical comparisons.
The app does not transmit personal journal entries, symptoms, sleep records, or wellbeing observations to Express Buy OÜ as part of its core functionality.
BioRhythm does not use personal wellbeing information for advertising, behavioral advertising profiles, or cross-app tracking.
Insights and associations are informational and do not establish medical causation. Users should not rely on BioRhythm as a substitute for professional medical advice.
BioRhythm uses device-provided date, time, time-zone, language, locale, and related system settings to record events, display journal entries, and perform time-based calculations.
This information is used for application functionality and is not used for advertising or cross-app tracking.
BioRhythm stores personal journal information primarily in a local database on the user's Android device.
The app allows users to:
create local backups;
restore compatible backup files;
export journal information in CSV and PDF formats;
import compatible CSV information;
manage and delete their journal entries.
Backup and export files may contain sensitive personal information, including symptoms, habits, notes, and wellbeing observations.
Users control where exported or backed-up files are stored, copied, or shared after creation.
BioRhythm does not provide an Express Buy OÜ cloud account or an application-operated cloud synchronization service for personal journal information.
Files stored through external storage providers or cloud services selected by the user may be processed under those providers' own privacy policies.
BioRhythm provides a 30-day free access period beginning with the app's first launch, without requiring a payment card or subscription enrollment.
After this period, continued access to certain editing and recording features requires an active Premium subscription.
BioRhythm Premium is offered through Google Play as an optional auto-renewing monthly subscription.
Subscription prices, billing periods, renewal terms, and applicable taxes are displayed by Google Play before purchase.
Purchase transactions are processed by Google Play. Express Buy OÜ does not receive or store full payment card or banking details through BioRhythm.
The app may receive and process Google Play purchase information necessary to determine subscription eligibility, acknowledge purchases, restore subscriptions, and manage access to Premium features.
Users can manage or cancel their subscriptions through Google Play. Canceling a subscription does not automatically delete locally stored journal data.
Google's handling of payment and transaction information is governed by its applicable privacy policies and terms.
BioRhythm uses Android platform functionality and Google Play services necessary to operate the app and manage subscriptions, including Google Play Billing.
These services may process technical, device-related, or transaction information according to their own applicable privacy policies.
BioRhythm does not use third-party advertising SDKs.
The app does not require a third-party analytics account or external service to calculate its personal wellbeing insights.
BioRhythm's personal analytics are calculated from locally stored journal information.
These calculations are intended to help users explore their own historical observations and possible patterns.
BioRhythm does not contain advertising.
BioRhythm does not use personal journal information to create advertising profiles, target advertisements, or track users across applications or websites.
Express Buy OÜ does not sell personal data collected through BioRhythm.
Personal wellbeing records are not sold to advertisers, data brokers, or other third parties.
BioRhythm does not intentionally transmit locally stored journal entries, symptoms, sleep information, mood observations, or personal notes to Express Buy OÜ as part of its core functionality.
Information may be processed by Android, Google Play, or user-selected file storage services when necessary to provide requested functionality, including subscription processing, backups, imports, and exports.
Users may choose to share exported files with other applications or services. Once shared, those files may be subject to the privacy practices of the receiving service.
Personal journal information is generally retained locally on the user's device until the user edits or deletes it, restores different data, clears application data, or uninstalls the application, subject to Android's storage and backup behavior.
Users can delete individual journal entries within the app.
Uninstalling BioRhythm or clearing its application data generally removes locally stored application data, subject to copies retained in Android backups or other storage locations.
Exported CSV files, PDF reports, and backup files saved outside the app remain under the user's control and may continue to exist after the app is uninstalled.
Purchase records maintained by Google Play are subject to Google's own retention policies.
Expiration or cancellation of a Premium subscription does not automatically delete locally stored journal information.
BioRhythm may use Android permissions and system capabilities necessary for its functionality, including:
Internet access for Google Play Billing and subscription verification;
device date, time, and language settings;
Android file selection and document storage interfaces for backup, restore, import, and export;
local application storage for journal entries and preferences.
BioRhythm does not require access to contacts, microphone, camera, or precise location for its current core functionality.
Permissions and system capabilities are used only as necessary to provide application features.
BioRhythm is intended for general personal wellbeing tracking and is not specifically designed or directed at children.
The app is not intended to provide medical services or clinical guidance to minors.
BioRhythm is designed to keep personal journal information on the user's device and limit unnecessary transmission of sensitive information.
Reasonable measures are taken to protect application data and support controlled backup and restore operations.
However, no method of electronic storage, communication, or data processing can guarantee absolute security.
Users should protect their devices and exported files, as backups, CSV files, and PDF reports may contain sensitive personal information.
This Privacy Policy may be updated when BioRhythm's functionality, data practices, legal requirements, or third-party services change.
The current version will be published at:
https://exbuy.ee/APPS/BioRhythm/privacy
The “Last updated” date will indicate the latest revision.
If you have questions about this Privacy Policy or BioRhythm's privacy practices, contact:
Express Buy OÜ
Paasiku tn 4-101
13916 Tallinn
Estonia
Email: info@exbuy.ee
Website: https://exbuy.ee