Privacy Policy
Last updated: July 22, 2026
Kotoba is a Japanese diary and writing-practice app for English-speaking adults. This policy explains what data the app processes and why.
What Kotoba processes
• Diary entries and learning data: Your diary text, titles, moods, AI corrections, vocabulary, and review history are stored on your device by default.
• AI feedback: When you choose “Send to AI Tutor,” the selected diary title and text are sent securely to our Firebase backend and AI service provider to generate Japanese corrections and English explanations.
• Account data: If you use optional Google sign-in, Kotoba may process your account identifier, name, email address, and profile image.
• Cloud backup: If you are signed in and use backup, diary entries and associated learning data may be stored in Firebase.
• Analytics and diagnostics: Production analytics may process app interactions, device or installation identifiers, crash and performance data, and approximate location inferred from an IP address. Diary text is never included in analytics events.
How data is used
We use data only to provide AI feedback, authentication, optional backup and restore, app reliability, usage measurement, abuse prevention, and support. We do not sell personal data or use diary text for advertising.
Sharing and security
Data may be processed by service providers needed to operate Kotoba, including Google Firebase and the AI model provider. Data is encrypted in transit. Access is limited to the services and personnel required to operate and support the app.
Retention and your choices
Local diary data remains on your device until you delete entries, clear the app’s storage, or uninstall the app. Cloud account and backup data is retained while needed to provide the service, unless you request deletion sooner.
Account and associated data deletion
To request deletion of your Kotoba account and associated cloud data, email seok7302@gmail.com from the email connected to your account with the subject “Kotoba account deletion.” State that you want both the account and associated Kotoba data deleted. We may ask you to verify account ownership. After verification, we will delete the Firebase account and associated cloud diary/learning data, except records that must be retained for security or legal obligations. We aim to complete verified requests within 30 days.
To remove local data immediately, delete entries in the app or use Android Settings → Apps → Kotoba → Storage → Clear data. Uninstalling Kotoba also removes app-local data according to Android behavior.
Children
Kotoba is intended for adults aged 18 and over.
Contact
Questions or privacy requests: seok7302@gmail.com