Privacy Policy

Last updated: May 9, 2026

This Privacy Policy explains how Kotonoki ("we", "us", "our") collects, uses, and shares information when you use our iOS application and website at kotonoki.addicted.design.

We aim to collect only what's necessary to make Kotonoki work and to keep it that way long-term. We don't sell your data and we don't use it for advertising.

1. Information we collect

Information you provide

• Account data: email address, optional display name, optional avatar image you upload yourself.
• Vocabulary & progress: Japanese words you save, lessons you take, your spaced-repetition state, your JLPT level preference.
• Subscription data: your subscription tier, whether you're on a trial, when it expires. Apple receipts are validated to confirm subscription status; payment details (card, etc.) are handled entirely by Apple — we never see them.
• Reports: if you tap "Report a problem" on a lesson, we receive what you flagged.
• Support emails: if you write to us, we keep the email thread for as long as needed to help you.

Information collected automatically

• Device push token: stored to send you the notifications you've opted into (daily phrase, streak reminders, new episodes). Removed when push fails repeatedly or when you delete the account.
• Anonymous activity: when you open a lesson or generate a new one, we record the action (with your account id) for analytics and quota enforcement. We do not record what you type or what you read.

Information from third parties

• Apple Sign In / Google Sign In: if you sign in via these, we receive a stable id, your email (or a Hide-My-Email relay), and optionally your name/avatar. We never receive your Apple/Google password.
• TMDB: we fetch anime metadata (titles, posters, episode lists, age ratings) from The Movie Database API. TMDB doesn't receive your personal data through us.
• Jimaku: we fetch Japanese subtitles from the open-licensed catalog at jimaku.cc. We send only the show / episode identifier; no personal data.

2. How we use information

• To create and run your account.
• To generate lessons, save vocabulary, and track your progress across devices.
• To deliver push notifications you've opted into.
• To enforce subscription limits and prevent abuse.
• To respond to support requests and fix bugs.
• To produce aggregate, anonymized statistics about app usage (e.g., "X total lessons generated this week"). These never identify individual users.

3. Third-party services we use

Kotonoki relies on the following infrastructure providers. They process your data only as needed to provide their service to us:

• Apple — App Store, Sign In with Apple, push delivery (APNs).
• Google — Sign In with Google (optional, only if you choose this method).
• Supabase — database, authentication, file storage, serverless functions.
• AI services — lesson content (text and illustrations) is generated by AI providers we contract with. Only the show / episode metadata is sent (e.g., "Frieren: Beyond Journey's End, episode 1, plot summary"). Your account id, email, vocabulary list, or any personal information are not sent to AI providers.
• TMDB — anime metadata. We send only the search query you typed and the show id you tap.
• Jimaku — Japanese subtitle source. We send only the TMDB / AniList id of the episode you've opened.

4. AI-generated content

Lessons, examples, and illustrations in Kotonoki are generated by artificial intelligence based on episode metadata and Japanese subtitles. AI output may occasionally contain inaccuracies — including wrong readings, mismatched JLPT levels, or imperfect translations. Use your own judgment and cross-check with authoritative sources (a dictionary, a teacher) for anything that matters. You can report problematic content via the in-app "Report a problem" action.

5. Data retention & deletion

We keep account data while your account is active. You can delete your account at any time:

• Open the app → Profile → Delete Account → confirm. This permanently removes your account, vocabulary, progress, and avatar within seconds.
• Or email kotonoki@addicted.design from the email tied to your account, and we'll do it for you.

Catalog content (shared anime entries, episodes, generated lessons) is decoupled from your account and remains available to other users after your deletion. Anonymized aggregate statistics may be retained for product analytics.

6. Children's privacy

Kotonoki is not directed at children under 13. We don't knowingly collect personal information from children under 13. If you believe a child has provided us with such information, please contact us so we can remove it. The app includes a content rating filter that lets adults restrict the catalog to family-friendly titles.

7. International transfers

Our infrastructure is hosted on cloud providers that may store and process data in regions outside your country (typically the EU, US, or Singapore depending on the service). By using Kotonoki you understand that your data may be transferred to and processed in these regions. We use providers that offer standard contractual safeguards.

8. Your rights

Depending on your jurisdiction (GDPR, CCPA, etc.), you may have the right to:

• Request a copy of your personal data.
• Correct inaccurate data.
• Delete your account and associated data.
• Object to or restrict certain processing.
• Lodge a complaint with your local data protection authority.

To exercise any of these rights, email kotonoki@addicted.design from the address on your account.

9. Security

We use industry-standard practices: TLS in transit, encrypted storage at rest, hashed and salted credentials handled by our auth provider. No method is 100% secure — we work to keep data safe but can't guarantee absolute security.

10. Changes to this policy

We may update this Privacy Policy from time to time. The "Last updated" date at the top reflects the latest version. Material changes will be communicated in the app.

11. Contact

Questions about this Privacy Policy or about your data: kotonoki@addicted.design.