Privacy Policy

Shindan 診断 · version 1.2 · last updated: 17 September 2026

Shindan 診断 measures your Japanese: one sheet under a clock, then your level and the one thing worth studying next. The measurement itself happens entirely on your device, with no internet connection. From version 1.2 there is one optional feature that does use it — the result debrief. A section below describes it, and it is the only place where anything leaves your phone.

Your account

There isn't one. Shindan never asks you to register, sign in or give an email address, and has no way of recognising you.

Where your results go

They stay on your device. Your answers, your results and your sheet history are not sent anywhere, do not sync with iCloud and are not accessible to me — there is no account, so there is nothing to sync. The one exception is named plainly and you start it yourself: the result debrief, described below. Deleting the app deletes this data with it.

Other apps of mine

Shindan can point you at another of my Japanese-learning apps when it finds a weak spot, and it opens that app if you have it. It reads nothing from those apps and writes nothing to them. The recommendation is worked out from your answers in this app alone.

Where the questions come from

The questions are built from the content catalogs of my other Japanese-learning apps. That material is written by me and ships inside the app file, so nothing is downloaded and nothing is streamed.

The debrief — the only thing that leaves your phone

From version 1.2, a finished sheet can get you a sentence about what your mistakes have in common — the thread running through them, rather than just a ranking of sections. A language model writes it, and this is the only feature in the app that uses the network. It runs only when you open it yourself; never in the background and never on its own.

What goes out: the measurement. Your level, and for each section its mark (助詞, 活用), how many questions were asked, how many you got right, and at most four confused pairs — the option you picked next to the correct one. Plus your interface language and a sheet identifier, which is how the server knows this is a second tap on the same result rather than a new question.

What does not go out: question text, sentences from the catalog, or anything written by you. The last one has no way out — this app has no text field at all and never will, because answers here are picked from ready options.

The request goes to my server at api.jd-japanese.pl and from there to the model. The answer comes back to the app and stays on your device. Neither your result nor the model's answer is stored — there is no column they could sit in.

Three technical things are kept on the server, because the feature cannot work without them: a hash of your App Store transaction identifier (so it knows this device owns the purchase), an App Attest key identifier with its public key (it confirms the request comes from a genuine copy of this app — it is created on your device, is unique to this one app, and is created afresh after every reinstall), and usage counters. Kept more briefly, for 90 days: request diagnostics — number, function name, model, status, token count, response time. IP addresses are not kept. None of this is tied to your name, address or account — the app does not know them.

A sheet too thin to produce a result gets no debrief and sends nothing: if too much ran out on the clock, there is nothing to discuss.

Tracking and advertising

None. The app contains no analytics library, no advertising library, no crash reporting and no tracking identifier.

Purchases

The first sheet is free. Further sheets are a one-time purchase handled entirely by Apple. Shindan never sees your payment details — it only asks StoreKit whether the purchase exists.

Notifications

There are none. Shindan measures once; it has nothing to remind you about.

Children

The app is rated 4+ and collects nothing that identifies anyone, a child included: there is no account, and it never asks for a name, an age or an address. What the server keeps for the debrief is described in the section above, and it is technical identifiers and counters only.

Changes

If this policy ever changes, the date at the top changes with it. This page's address carries the app version, so older releases always point at the document that actually described them.