Terms of Use
Joshi · version 1.5 · last updated October 2, 2026
What this app is
Joshi is an educational app for practicing Japanese particles. It is not a course or advice, and it needs no account. The learning — levels, practice and progress — runs entirely on your device.
Version 1.5 adds a separate, optional feature: the “Sentences” tab with an “AI” badge, in which a language model explains what each particle does in someone else's sentence (“Explain”), or assesses the particles in your own sentence — each one right, wrong, or “works, but…” (“Check mine”). It is paid for with the subscription described below.
License
The app is licensed under Apple's standard licence terms (Licensed Application End User License Agreement). These terms supplement them and cover what applies to Joshi only; where the two conflict, Apple's terms prevail. You may not resell the app, decompile it, or extract the study material from it in order to pass that material on.
The Premium purchase
Premium is a one-time non-consumable purchase, with no automatic renewals. It opens levels 3 through 5, the full pool of sentences, and practice on the confusable pairs you get wrong most. Levels 1 and 2 stay free in their entirety.
Purchases are processed by Apple under the App Store terms. Refunds are handled by Apple, not by the developer — request one at reportaproblem.apple.com. “Restore purchases” re-checks your entitlements on any device signed in with the same Apple Account.
AI Help — auto-renewing subscription
The “Sentences” tab is the only part of the app that costs money every time it is used, which is why it is sold as a subscription rather than a lifetime purchase.
- Everyone gets a free sample every month — currently 5 requests — with or without Premium and without a subscription. The app shows how many are left and when they come back.
- An answer with nothing to show — when the sentence has no particle — does not use up a request from your allowance.
- More requests come with the AI Help subscription, monthly or yearly. The app shows the price and the period before you buy, in your currency. The subscription has a daily and a monthly request limit that protects the service from abuse.
- The subscription renews automatically until you turn it off. The charge for the next period is taken from your Apple Account within 24 hours before the current period ends.
- Cancelling: in your Apple Account settings (Settings → your name → Subscriptions) or with the Manage subscription button in the app, at least 24 hours before the current period ends. The subscription keeps working until the end of the period you paid for.
- The subscription does not unlock levels 3–5, and Premium does not include the subscription. They are two separate products; material bought once stays yours regardless of the subscription.
- The “Sentences” tab needs an internet connection and may be temporarily unavailable — during maintenance, for example, or an outage at the model provider. The rest of the app keeps working normally.
Accuracy of the material
The sentences and the variants are written for this app and covered by tests, but a natural language has exceptions and registers that no set of rules covers completely. This app does not replace a dictionary, a textbook, or a teacher. If you find a sentence that looks wrong, write in — reports like that come first. The material may not be reproduced, redistributed or used to train machine-learning models.
Answers in the “Sentences” tab
Explanations and assessments of particles are generated by a language model, and they can be wrong — including where two particles are both correct, or where a sentence without its context is ambiguous. “Check mine” assesses particles only; other mistakes in the sentence are not what it answers. Treat the answer as a starting point to check, not as a tutor's opinion or an exam grade. It does not count towards your progress or your reviews.
Your data
Your study progress is stored on the device alone. Use “Export progress” in Settings if you want a copy; importing one replaces everything on the device it is imported into. We have no access to your progress and no way to recover it once you delete the app or reset your progress. The exception is the “Sentences” tab, and only when you tap the button yourself: the sentence you typed is sent to the server. What exactly is kept, and for how long, is set out in the privacy policy.
Liability
The app is provided “as is”. To the extent permitted by law, the author is not liable for damages arising from its use, including the loss of study data. None of this limits consumer rights granted by mandatory provisions of law.
Changes to these terms
These terms may change as the app develops. The address of this page carries the version number, so each release points to the terms that actually apply to it; a change within a version changes the date at the top.
Governing law
Polish law, subject to the mandatory consumer-protection provisions in force in your country of residence.