Privacy Policy

The short version. Mekuri stores your notes with your account so that you can study them, and sends them to an AI provider to make questions. Only you can see them. They are not used to train AI, they are not sold or shared, and there are no ads or analytics in the app. You can export everything or delete your account at any time from the app.

This policy explains what Mekuri does with information. It applies to the Mekuri mobile app, published by Ludicrous, inc. (株式会社LUDICROUS), Japan.

Your account

You do not need to sign up. When you first open Mekuri, it creates an anonymous account so that your notes can be stored. You can later link it to Apple or Google so that you can sign in again on another phone. Mekuri does not ask Apple for your name or email address. If you link Google, the email address of that Google account is stored with your account (in Firebase Authentication).

What we store

To run the app, we store the following for your account. Only you can see it; it is not shown to other users.

An account ID, and the Apple or Google account you link (for Google, its email address)
The notes you add: the photos and PDFs, the text read from them, and the questions made from them
Your answers, the marking of written answers, your review schedule and study history
Your exams, practice exams, reminder time and language settings
Summaries of marked tests you add: sections, question types, topics and where marks were lost. The photos are deleted once the analysis is done, and the wording of the test is not stored
Your school and year, if you choose to enter them (schools in Japan only, from the Ministry of Education’s school code list)
Reports you send about a question, and a request to correct your birth date if you send one. When you report a question, our team reviews that question (with its answer and source excerpt) and your comment to improve how questions are made; our review screen does not show who sent it
Your plan, and how much of its allowance you have used

These are stored in Google Firebase (Authentication, Cloud Firestore, Cloud Storage and Cloud Functions) in the Tokyo region (asia-northeast1). Your birth year and month are checked on the phone and are not saved.

What stays on your device

Mekuri stores the following on the device itself. We never receive it, and it is not backed up to any service we operate:

Reminders and exam notices, which are scheduled on the phone itself — we do not send push notifications
The number of questions left today, for the home screen widget
Which tips you have dismissed
If the age check shows you are under 13, a marker that stops the app from being used on that phone (not your birth date)

Because your notes are stored with your account, changing phones does not lose them — as long as you have linked Apple or Google, so that you can sign in again. An account that is not linked cannot be moved to another phone, and may be lost if you delete the app.

What leaves your device

The following, and nothing else:

What	Who receives it	Why
Your account ID, the notes you add (photos, PDFs, the text read from them and the questions made from them), your answers, study records, exams and settings	Google (Firebase), our cloud provider, in its Tokyo region	To store them for your account and run the app
The pages you add, photos of marked tests you add, and the written answers you ask to have marked	Google (Gemini API), our AI provider	To read the pages, make questions, analyze marked tests, and mark written answers. Under the paid Gemini API terms, Google does not use this data to improve its products or train its AI; it may keep it for a limited time only to detect misuse and meet legal requirements
Crash and error reports: which step failed, an error code, and technical details about the device and app version. Never the content of your notes or answers	Google (Firebase Crashlytics)	To find and fix problems
A check that a request comes from the genuine app	Apple (App Attest) or Google (Play Integrity)	To stop other software from using our servers
Your purchase receipt, your account ID, and basic device information	RevenueCat, our subscription provider	To verify purchases, prevent fraud, and keep your plan active
The purchase itself	Apple or Google	To process payment and manage renewal

Data sent for these purposes is encrypted in transit. These providers process it on our behalf as service providers, and do not use it for their own advertising.

What we do not do

We do not use analytics, advertising, or tracking software in the app.
We do not track you across other companies' apps or websites, and we do not collect an advertising identifier.
We do not sell or share personal information, and we never have. There is nothing to opt out of.
We do not use your notes, tests or answers to train AI, and neither does our AI provider.
We do not send push notifications. Reminders are scheduled on your phone.
We do not show your notes, school or study records to other users. There is no sharing feature.

Children

Mekuri is for people aged 13 and over. When you first open it, the app asks for your birth year and month and works out your age on the phone; the date itself is not saved. If you are under 13, the app cannot be used. If you entered the date by mistake, you can send us one request to review it — please do not include your name, school or contact details. We do not knowingly collect information from anyone under 13.

Deleting your data

You can delete your account and everything stored for it at any time, from inside the app. The steps, what is deleted and what is kept are on Deleting your account.

In the Settings tab, Export my data saves your notes, questions and records as a JSON file. Photos and PDFs are not included.

To have the purchase information described above deleted, email support@ludicrous.co.jp from any address and tell us which store you purchased from. We will delete the subscription record we hold. Note that this does not cancel an active subscription — the store handles that — and that Apple and Google keep their own transaction records under their own policies.

Where your data is handled

We are based in Japan. Your account and notes are stored in Google Firebase in Japan (Tokyo region). The Gemini API, which reads your pages and marks your answers, and Firebase Crashlytics are run by Google and may process data in other countries, including the United States. Our subscription provider, RevenueCat, processes purchase information in the United States. By using Mekuri you understand that the information described above may be processed in those countries.

Changes

If this policy changes, the updated version appears on this page with a new date at the top. Changes that affect what leaves your device will be described in the app's release notes as well.

Contact

Ludicrous, inc. (株式会社LUDICROUS)
support@ludicrous.co.jp