Privacy Policy
brain-detox (the "App") respects your privacy and collects only the minimum information needed to operate. This policy describes what data the App handles, how it is used, where it is stored, and what rights you have.
1. Data We Collect
1-1. Anonymous Identifier
The App uses Firebase Authentication's anonymous sign-in to issue a unique anonymous ID (UID) for each user. This ID is not linked to your name, email, phone number, or any other personal information.
1-2. In-App Data
The following data is stored on our servers (Google Cloud Firestore, Tokyo region asia-northeast1):
| Data | Description | Purpose |
|---|---|---|
| Partner selection | Selected partner type | Personalize action suggestions |
| Brain score | Numeric 0 E00 | Core app feature |
| Language preference | ja / en / th | UI localization |
| Score history | Records of actions and tests (up to 60 entries) | History display, streak calculation |
| Notification settings | Enabled/disabled, reminder times | Device-only |
| Badge progress | Device-only | Achievements display |
| Rate limit counter | Daily API call count | Service protection |
1-3. Device Permissions
The App uses only notifications (push, optional). It does not access location, contacts, camera, microphone, photo library, health data, or advertising identifiers (IDFA / AAID).
2. Third-Party Services
2-1. Firebase (Google LLC)
The App uses Firebase services (Authentication / Firestore / Functions / App Check).
Firebase Privacy & Security: https://firebase.google.com/support/privacy
2-2. OpenAI (OpenAI, L.L.C.)
To generate action suggestions and partner messages, the following is sent to the OpenAI API (US servers):
| Sent | NOT Sent |
|---|---|
| Current brain score (0 E00) | Anonymous UID |
| Selected partner type | Device information |
| Language preference | Personally identifiable info |
| Recent action summary (max 3 titles) | Detailed score history |
Per OpenAI's policy, data sent via the API is not used to train OpenAI models.
OpenAI API data usage: https://platform.openai.com/docs/models/how-we-use-your-data
2-3. Expo (Expo, Inc.)
The App is built with Expo, but no user data is sent to Expo's servers.
3. Data Retention and Deletion
3-1. Retention
Even after you uninstall the App, data stored in Firestore is retained so that re-installation can restore the same anonymous UID.
3-2. Deletion
- In-App: Settings ↁEReset Data
Removes profile and score history stored in Firestore. Erases all local settings. - By Request
Email the contact below. Including your anonymous UID (visible in Settings) speeds up the process.
4. Disclosure to Third Parties
We do not disclose or sell user data to any third party, except as required by law.
5. Children's Privacy
The App is not intended for users under 13. If a parent or guardian discovers that a child under 13 is using the App, please delete the data using the methods above.
6. Your Rights
Under GDPR, CCPA, and other applicable laws, you have:
- Right to access your stored data
- Right to rectification
- Right to erasure ("right to be forgotten")
- Right to object to processing
- Right to data portability
7. Security
- All communication is encrypted via HTTPS / TLS
- Firestore Rules ensure each user can only access their own data
- The OpenAI API key is held in Firebase Functions Secret Manager and never exposed to clients
- Firebase App Check ensures requests originate from a legitimate app build
8. Cookies and Tracking
The App is a mobile application and uses no cookies. It uses no advertising or tracking identifiers.
9. Changes to This Policy
This policy may be updated without prior notice. Material changes will be announced via in-app notification or app update notes.
10. Contact
- Contact email:
l.ikeda.937@gmail.com - App name: brain-detox
- Operator:
池田怜雄
This policy is provided in Japanese, English, and Thai. In case of any discrepancy, the Japanese version prevails.