Privacy Policy

Effective: July 17, 2026

Welcome to Mongle Haru. We respect your privacy and are committed to protecting your personal information. This Privacy Policy explains how we collect, use, and safeguard your data when you use our app.

1. Information We Collect

Mongle Haru's diary features do not require you to create an account. If you only use the diary, we do not collect any personal information from you.

Diary Data: All diary entries, photos, stickers, and emotional records are stored locally on your device. This data never leaves your device unless you choose to enable cloud backup.
Cloud Backup (Optional): If you enable cloud backup, we use Google Drive or Apple iCloud to sync your diary data. We authenticate your Google or Apple account solely for this purpose.
Mongle Mailbox (Optional Feature): If you use the Mongle Mailbox (letters and replies), we collect and process:
- Account identifier from your Google or Apple sign-in
- The letters you write, your selected mood sticker, and your language setting
- Optional profile details you choose to share (the name your character calls you, and a short "about me" note)
- Reply history and conversation context derived from your past letters and replies (used to personalize future replies)
- A push notification token (only if you allow reply notifications), your app version, and platform (iOS/Android)
Paid Subscription (Optional): Purchase receipts and transaction identifiers used to verify your subscription. Payment itself is handled by the Apple App Store or Google Play; we never receive your card or payment details.
Advertising Data: We use Google AdMob to display ads. AdMob may automatically collect:
- Device identifiers (IDFA on iOS, Google Advertising ID on Android)
- Device information (model, OS version, screen size)
- IP address and general location
- Ad interaction data
Analytics Data: We use Firebase Analytics to collect app usage events such as screen views and feature usage in a non-identifying format.
Stability Data: We use Firebase Crashlytics to collect crash logs and error diagnostics for service stability.

2. AI-Generated Replies (Mongle Mailbox)

Replies from your Mongle characters are created with generative AI. They are not written individually by a human. The AI writes each reply based on your letter and your conversation context, in the voice of your character.

To generate replies, your letter text, optional profile details, and conversation context are processed by our AI provider, Anthropic PBC (United States).
Your account identifier, email address, push token, and device identifiers are never sent to the AI provider. Letters are pseudonymized with a randomly generated processing ID before AI processing.
We apply and maintain opt-out settings so that your data is not used to train AI models.
AI replies are not a substitute for professional medical or mental-health care, diagnosis, treatment, or emergency support. If you are struggling, please reach out to a professional or a trusted support service.

3. A Note on Sensitive Information

Mongle Haru never asks you to provide sensitive information such as health conditions, diagnoses, or medication details. Letters and profile notes are free-form, so you may choose to write about personal topics — but we recommend avoiding sensitive details.

Any sensitive content you voluntarily include is used only to generate your reply and, where needed, to show you safety resources. It is never used for any other purpose.
If a letter shows signs of crisis (such as self-harm), we may send a safety-focused reply that includes verified support resources for your region.

4. International Data Processing

To operate the Mongle Mailbox, we process data with the following service providers outside your country:

Recipient	Location	Data	Purpose & Retention
Fly.io, Inc. ([email protected])	Servers in Japan (Tokyo); company based in the U.S.	Mailbox letters, profile details, reply history, account identifier, push token, app version/platform	Hosting and operating the mailbox service; kept while the service is provided or until you request deletion
Anthropic PBC ([email protected])	United States	Letter text, profile details, conversation context (pseudonymized; no account identifier, email, or push token)	Generating AI replies; processed only as needed, with model-training opt-out applied

All transfers use encrypted (TLS) connections. You may object to this processing by contacting us below; in that case, the Mailbox feature may become unavailable to you.

5. How We Use Your Information

Cloud Backup: To authenticate your Google or iCloud account and sync your diary data across devices (only if you enable this feature)
Mongle Mailbox: To receive your letters, generate and deliver replies, keep conversation continuity, prevent abuse, and show safety resources when crisis signals are detected
Subscriptions: To verify purchases and provide paid features
Advertising: To serve personalized or non-personalized ads through Google AdMob and support the app's development
Analytics: To understand feature usage and improve product quality
Crash Monitoring: To detect, diagnose, and fix application errors quickly

We do not sell, rent, or share your personal information with third parties for their marketing purposes.

6. Data Storage & Retention

Diary data is stored locally on your device in the app's secure sandbox and is deleted when you delete the app. We do not have access to it (except optional cloud backup via Google Drive or iCloud, which you control).
Mailbox data (letters, replies, profile, conversation context) is stored on our access-controlled server for as long as the mailbox service is provided, and deleted without undue delay when you request deletion.
Purchase verification records are kept for the period required by applicable law.

7. Third-Party Services

Mongle Haru uses the following third-party services:

Google AdMob: For displaying ads. AdMob collects and processes data as described in the Google Privacy Policy.
Firebase Analytics / Crashlytics: For usage analytics and crash diagnostics. Data is processed under the Google Privacy Policy.
Apple iCloud: For optional cloud backup (iOS only). Data is stored according to Apple's privacy practices.
Google Drive: For optional cloud backup. Data is stored according to Google's privacy practices.
Fly.io: For hosting the Mongle Mailbox server (see Section 4).
Anthropic: For generating AI replies (see Sections 2 and 4).

8. Children's Privacy

Mongle Haru is not directed at children under the age of 13, and we do not knowingly collect personal information from children under 13. The Mongle Mailbox additionally requires users to be at least 14 years old.

If we become aware that we have inadvertently collected personal information from a child below these ages, we will delete it without undue delay. If you believe your child has provided us with personal information, please contact us at [email protected].

9. Your Rights

You have the following rights regarding your data:

Access: You can view all your diary data within the app at any time, and request a copy of your mailbox data by email.
Correction: You can edit or update your diary entries and mailbox profile at any time.
Deletion: You can delete diary data within the app. To delete your mailbox data (letters, replies, and conversation context) from our server, contact us by email and we will erase it without undue delay.

California Residents: If you are a California resident, you have additional rights under the California Consumer Privacy Act (CCPA), including the right to know what personal information we collect, the right to delete your personal information, and the right to opt-out of the sale of personal information. We do not sell personal information.

To exercise your rights, please contact us at [email protected].

10. Data Security

We take reasonable measures to protect your data. Your diary data is stored locally on your device in the app's secure sandbox, protected by your device's operating system security features. Mailbox data is transmitted using industry-standard encryption (TLS) and stored on an access-controlled server, accessible only to the minimum personnel needed to operate the service. If you enable cloud backup, your data is transmitted using industry-standard encryption (TLS) and stored securely by Google Drive or Apple iCloud.

Analytics and crash diagnostics do not include your diary content body, original photo files, or raw search keywords.

However, no method of electronic storage or transmission is 100% secure. While we strive to protect your data, we cannot guarantee absolute security.

11. Changes to This Policy

We may update this Privacy Policy from time to time to reflect changes in our practices or legal requirements. We will notify you of any material changes at least 7 days in advance through an in-app notification. Your continued use of the app after the effective date of the updated policy constitutes your acceptance of the changes.

February 19, 2026: First published
July 17, 2026: Updated — added Mongle Mailbox data collection and retention, generative AI disclosure, sensitive information notice, children's age requirements, international data processing, and subscription records; corrected the description of data storage scope

12. Contact Us

If you have any questions, concerns, or requests regarding this Privacy Policy or our privacy practices, please contact us at:

Email: [email protected]