プライバシー Privacy Policy

This policy describes what ミステリー日本語 keeps and what it sends. It is written PDPA-first for Singapore and is suitable for a mixed-age audience.

On your device

• Your progress — the steps done, the seals on each word, the kana learned, your dictation scores, the mock tests you have sat with the answers you gave, and how each word, question and grammar point has gone in 復習 — and your settings are stored in your browser's local storage on your own device. Unless you sign in, none of it is sent to us.
• Handwriting is checked on your device. The strokes you draw are not sent anywhere.

If you sign in

• Signing in is optional. When you sign in with Google or with a link sent to your email, we keep your email address, an account ID and a copy of your progress with Google Firebase (Google LLC), our account and database provider, so your progress follows you to every device where you sign in. The copy also holds the date you first opened the app, so the free week counts from then on every device. Only your account can read that copy.
• When the app opens, it connects to Firebase, which gives this browser an anonymous ID of its own. The app uses it to check for a subscription. Nothing about you is sent with it until you sign in.
• Opening mock papers 2 to 5 sends that ID to japanese.tips, which asks Firebase whether the ID has a subscription or is in its first week, and then sends the paper.
• If you connect an AI agent to your account (japanese.tips/authorize, which the agent opens), we keep your account ID, the agent's name and address, and your sign-in's refresh token, encrypted, with Cloudflare (our host). The agent can then read your mock papers 2 to 5 while your subscription or first week lasts. Each time it does, japanese.tips uses the refresh token to ask Firebase whether you are still signed in and subscribed. A connection unused for 30 days ends; signing out everywhere ends it too, and Settings, Account lists the agents connected and disconnects any of them.
• In the Android app, signing in with Google uses your phone's own Google account picker.

If you subscribe

• Subscribing requires signing in, so the subscription follows you to every device where you sign in. Its record holds your plan, its renewal date and status, and the payment provider's references for it; only your account can read it.
• On the web, payment is handled by Airwallex on its own hosted page: card details are entered there, and we do not receive or store card numbers. If your sign-in address is verified, we give it to Airwallex so the receipt reaches you.
• In the Android app, payment goes through Google Play under Google's terms. Google tells us the order's reference and whether the subscription is active, renewing or ended.
• When you choose a plan, Google reCAPTCHA checks that the request comes from this app and not from a script (Firebase App Check). It reads information about your browser and device under Google's Privacy Policy and Terms of Service.

What the app loads

• The app's files — its scripts, fonts, lessons and stroke-order data — come from our host, Cloudflare. Those requests carry the standard technical data any web request does, such as your IP address, handled under Cloudflare's policies.
• We count visits with Cloudflare Web Analytics. When the app loads, it reports the page, the site you came from, how fast the page loaded, and your browser, device type and country. It uses no cookies and does not identify you or follow you to other sites, and it never sees your progress, which stays on your device.
• We count requests to the reference pages under japanese.tips/jlpt and to the endpoints AI agents use, by kind of request and kind of browser or program (for example "a web browser" or "ClaudeBot"). The count keeps no IP address, no account and nothing that identifies you.
• The app contains no advertising.

Listening

Japanese is read aloud by your browser's built-in text-to-speech. Voices installed on your device are used first, and they speak on the device. If it has none, your browser may use an online voice, which sends the Japanese being read — the lesson's own text, never anything you enter — to the browser maker's service (for Chrome, Google). When one is in use, the app sends it a single silent syllable when you start using the app and after a minute without speech, so that a line plays without a wait.

In the Android app, Japanese is read by your phone's own text-to-speech engine (on most phones, Google's Speech Services), which speaks on the phone or, if the engine is set to, uses its online voices.

Children

Without signing in, the app collects no personal data (the visit counts above identify no one), so a child can use it without providing any. Signing in keeps an email address, as above. Subscriptions are intended to be bought by an adult.

Your choices

最初から (Start over) in 設定 erases your progress, and if you are signed in, the copy on your account too. Clearing your browser's site data for this app erases everything it stored on the device. To delete your account, or for any question about data, write to support@latticelogic.app.

Deleting your account

1. To erase only your progress, open 設定 and tap 最初から (Start over). This clears it on the device and, if you are signed in, on your account.
2. To delete your account, email support@latticelogic.app from the address you signed in with, or name that address in the message.

We delete your email address, your account ID and the copy of your progress within 30 days and reply when it is done. Records of any payment are kept for as long as tax law requires. Nothing else is kept.