Privacy Policy

Last updated: 2026-09-29

This policy explains how Nihonzo (“we”, “us”) handles information in the Nihonzo mobile app for iOS and Android (the “App”) and on this website. If you have any question, contact us at nihonzoofficial@gmail.com.

1. What stays on your device

We do not collect or store personal data on servers of our own. The App keeps the following only on your device:

• Your study progress, bookmarks, settings, saved video lessons, and your AI key and AI history.
• A random install ID and the date the App was first opened, used on the device to give each device one 7-day free trial. On iPhone and iPad they are kept in the device's secure storage (Keychain) so reinstalling doesn't restart the trial; they never leave the device and say nothing about you.
• A copy of your App Store purchase history for the App, read from Apple on the device to unlock the plan you bought.

Uninstalling the App deletes this data, except the Keychain install ID and first-launch date described above.

2. Purchases

Paid plans are bought through Apple's App Store or Google Play, which process the payment under their own terms and privacy policies (Apple, Google). The App checks the purchase record that the store provides on your device. We never see your name, payment card or store account. The stores give developers sales reports that do not identify individual buyers.

3. Features that connect directly to other services

Some features work by connecting your phone straight to a third-party service. We don't receive, see or store what is exchanged; the third party's own privacy policy applies.

• AI features (Ask AI, AI explanations, YouTube lessons) — use the provider you choose (OpenAI, Google Gemini or DeepSeek) with your own API key. The text you ask about — your question, a sentence or word you selected, or a video's captions — is sent from your phone to that provider. Your key and AI history are stored only on your device and are not included in backup files. Don't send personal information to the AI.
• News and the in-app reader — headlines are downloaded directly from the news sites' public feeds (for example NHK, Asahi, Yahoo! News Japan) and any sites you add, and articles open from those sites. Like any website, they can see your IP address and may use cookies. Ranking headlines to your level happens entirely on your phone.
• YouTube — videos and their captions are loaded from YouTube (Google), which receives data as described in the Google Privacy Policy. Videos you add and the lessons generated from them are saved only on your device.
• Speech recognition (conversation role-play) — uses your phone's built-in speech recognition from Apple or Google, which may process your voice on their servers under their privacy policies. It only runs while you hold the record button, and only after you grant microphone permission. Pitch-accent practice analyses your recording on the device.
• Study reminders are scheduled on your device; no server is involved.

4. Contacting us

If you email us or message our Facebook page on Messenger, we use your email address or Facebook name and what you write only to answer you, and keep the conversation only as long as needed to help you. Ask us and we will delete it. Messenger conversations are also processed by Meta under the Meta Privacy Policy.

5. This website

This website is a set of static pages hosted by Google (Firebase Hosting). It uses no cookies, no analytics and no forms. Like any website host, Google processes technical data such as your IP address to deliver the pages and protect them from abuse (Firebase privacy information).

6. Children

The App is a study tool. It contains no ads and no social features, and we do not collect personal information from anyone, including children. If you are a parent and believe your child has sent us personal information (for example by email), contact us and we will delete it.

7. Your choices and rights

You can turn off AI features at any time by removing your key in Settings. Because we keep no data about you on our servers, there is nothing for us to access, correct or delete there; uninstalling the App removes the data on your device (see Delete my data). For purchase records, contact Apple or Google. Depending on where you live, you may also have the right to complain to your local data protection authority.

8. Changes

We may update this policy. If we add features that store data on our servers (for example, activation codes), we will update this policy before they go live. The “Last updated” date above shows the latest version; significant changes will also be noted in the App or on this site.

9. Contact

Nihonzo — nihonzoofficial@gmail.com · Messenger