Miuu Studio created the Miuu Note - Diary With Lock app as a free application with optional in-app purchases and ads. The base version of this Service is provided at no cost and is intended for use as-is. Users can opt to purchase a subscription or a one-time permanent upgrade for an ad-free experience and access to premium features.
This Privacy Policy informs users about how their Personal Information is collected, used, and disclosed when using this Service. By using the Service, you agree to the collection and use of information as described in this policy.
Information Collection and Use
The app may request personally identifiable information for a better user experience. When you sign in with Apple Login or Google Login, we collect your email address and display name for account identification and customer support purposes. This information is stored securely on our servers powered by Google Cloud. User-generated content (such as diary entries and images) is stored on your device by default. It leaves your device only when you use our backup service (see “Data Backup and Storage”) or when you choose to enable optional AI-powered features (see “AI Features and Third-Party AI Processing”). We do not otherwise collect your diary content. Limited anonymous or pseudonymous usage data may be collected through third-party analytics services for product improvement, as described below.
However, the app uses third-party services that may collect data to identify you. These include:
- Google Play Services
- PostHog (Product analytics)
Analytics & Product Usage Data
We use a third-party analytics service (PostHog) to understand how users interact with the app and to improve features, usability, and performance.
PostHog may collect anonymous or pseudonymous usage data, such as:
- App feature interactions (e.g., button taps, screen views)
- Device type, operating system, and app version
- Approximate location (derived from IP address, anonymized)
- Event timestamps and session duration
What we do NOT collect through analytics:
- Diary content or text entries
- Photos, images, or attachments
- User names, email addresses, or login credentials
- Any personally identifiable journal data
Analytics data is used strictly for product improvement and is never sold or used for advertising purposes. For more information, please review PostHog's Privacy Policy.
Note: Email addresses and display names collected at sign-in are used solely for account management and customer support, not for analytics or advertising purposes.
Data Backup and Storage
Account Information: When you sign in, your email address and display name are stored on our secure servers (Google Cloud Firestore) for account identification, customer support, and data recovery purposes. This account metadata is stored separately from your diary content and is not used for marketing or advertising.
Apple Login Users: For users who sign in with Apple Login, we use our secure backup system powered by Google Cloud Storage to back up user-input data (such as diary entries). This ensures your data is recoverable if you switch devices or reinstall the app. Miuu Studio retains management control of the data stored on Google Cloud but does not directly access or read your personal content. For more information, please review Google Cloud's Privacy Policy.
Google Login Users: For users who sign in with Google Login, you can choose between two backup methods:
- Cross-Platform Backup (Recommended): Your data is backed up to our secure servers powered by Google Cloud Storage. This provides seamless backup and restore across both iOS and Android devices. Miuu Studio retains management control of the data stored on Google Cloud but does not directly access or read your personal content.
- Google Drive Backup: Your data is backed up directly to your personal Google Drive. This means no data is sent to or stored by Miuu Studio. You retain full ownership and control of the data stored in your Google Drive.
Please refer to Google's Privacy Policy and Google Cloud's Privacy Policy for details on their data handling practices.
AI Features and Third-Party AI Processing
The app offers optional, AI-powered features (for example, features that answer questions about your notes, or that automatically organize the people, places, and themes you write about). These features are turned off by default and only operate if you explicitly turn them on. They are intended for adult users (18 and older).
If you enable an AI feature, the text of the relevant notes is sent to a third-party AI provider, Anthropic (the maker of Claude), to process your request. Depending on the feature, this may happen only when you ask a question, or continuously in the background as you write. We never send your photos, images, or voice notes to the AI provider — only text.
Under our commercial agreement with Anthropic:
- Your content is not used to train AI models.
- Your content is processed to return a result and then deleted by the provider a short time afterward; it is not retained long-term.
- Miuu Studio does not keep the AI results on our servers beyond what is needed to operate the feature (such as counting usage against any free limit).
You can decline these features and continue using the rest of the app normally, and you can turn them off at any time. Because these features send the content of personal journal entries to a third party, we do not knowingly make them available to, or process the content of, children. For details on how the provider handles data, please review Anthropic's Privacy Policy.
Log Data
If the app encounters an error, it collects data such as your device's IP address, name, operating system, and usage statistics through third-party services. No user-input data is ever collected.
Cookies
The app itself does not use cookies but may include third-party code or libraries that do. You can choose to accept or refuse cookies in your settings, but some features may be affected.
Third-Party Service Providers
- Facilitate the Service
- Perform Service-related functions
- Analyze Service usage
These providers may access your Personal Information but are obligated not to misuse it.
Security
We take reasonable measures to protect your Personal Information but cannot guarantee absolute security due to the nature of internet transmission and electronic storage.
Data Breach Response
In the event of a data breach that may affect your Personal Information, we will:
- Investigate the incident promptly and take immediate steps to contain the breach
- Notify affected users within 72 hours of discovering the breach, where technically feasible
- Provide details about what information was involved, steps we are taking to address the breach, and recommended actions for users
- Comply with applicable data protection laws and regulations regarding breach notification
- Implement additional security measures to prevent similar incidents
Limitation of Liability
While we implement industry-standard security measures and follow best practices to protect your data, we cannot be held liable for:
- Unauthorized access due to user negligence (sharing passwords, using insecure devices, etc.)
- Breaches caused by third-party services beyond our control (Apple iCloud, Google Drive, etc.)
- Acts of nature, cyber attacks, or other events beyond our reasonable control
- Data loss, corruption, or unavailability resulting from device failure, app deletion, user error, or failed backup/restore processes.
Our liability is limited to the maximum extent permitted by applicable law. We recommend users maintain their own backups and use strong, unique passwords.
Links to Other Sites
The app may contain links to external websites. Miuu Studio is not responsible for the privacy practices or content of these sites. Review their Privacy Policies for more information.
Children's Privacy
This app is intended for users aged 18 and older and is not directed to or designed for children. On the Google Play Store it is declared for a target audience of 18 and over.
Consistent with the Children's Online Privacy Protection Act (COPPA), we do not knowingly collect personal information from children under 13, and we do not knowingly send any child's content to third-party AI providers. The optional AI features described above are intended for adult users only. If we learn that we have collected personal information from a child under 13 without appropriate parental consent, we will delete it.
Parents or guardians who believe their child has provided personal information to us should contact us immediately at support@miuustudio.com for prompt deletion of such information.
Changes to This Policy
This Privacy Policy may be updated occasionally. Users are encouraged to review this page regularly. Changes will be posted here and are effective immediately.
Effective Date: July 16, 2026
Contact Us
For questions or suggestions, contact us at: support@miuustudio.com