Terms of use

Last updated: 22 August 2026

1. Scope

These terms govern your use of Vatlog ("the app"), an iOS / iPadOS application published by freetokyo ("the developer"). By using the app you agree to them.

2. What the app is

The app is a record-keeping and calculation tool for people who ferment beverages at home.

It does not provide legal advice. Rules about home fermentation differ by country, state and locality, and they change over time. The app does not determine what applies to you. Any annual target shown in the app is a figure you set.

Where the app offers a reference figure, it shows the statute citation behind it and the date the developer last checked it. That is an offer of information, not a determination. Confirm any figure against its source before relying on it. If the law has since changed, the data in the app may not be current.

The app also cannot verify what you produce. It has no way of establishing whether an alcohol content meets any particular threshold. Complying with the law where you live is your responsibility.

3. Calculations

The app's calculations are estimates derived from published formulas. Hydrometers and refractometers carry their own measurement error, and the formulas themselves have limits to where they apply. Where the app shows the result of more than one formula side by side, it is showing that formulas disagree — not deciding between them.

The developer makes no warranty as to the accuracy or completeness of any calculated result.

4. Your data

Your data is stored on your device, not on any server of the developer's.

Backing up your data is your responsibility. Data can be lost through device loss, damage or reset, through deleting the app, or through operating-system faults. The app can export JSON and ZIP files; before changing devices, export the ZIP, which includes your photos.

The accuracy of what you record is your responsibility.

5. In-app purchase

Vatlog Pro is a single non-consumable in-app purchase. There is no subscription and nothing renews.

The purchase is made through Apple and tied to your Apple Account, so it can be restored on any device signed in to the same account. Refunds are at Apple's discretion. If Apple refunds the purchase, the paid features stop working, but none of your data is deleted — affected batches become read-only and can still be viewed and exported.

6. Restrictions

You may not decompile, modify or redistribute the app, or use it for any unlawful purpose.

7. No warranty

The app is provided as is. To the extent permitted by law, the developer makes no warranty, express or implied, that the app will be fit for any particular purpose, will run without interruption, or that anything it displays or calculates is accurate, complete or current.

8. Limitation of liability

Except in cases of wilful misconduct or gross negligence, the developer's liability for any loss arising from use of, or inability to use, the app is limited to the amount you paid for the app.

Where mandatory law does not permit such a limitation, this clause applies only to the extent the law allows.

9. Changes

These terms may change. If they do, this page and its last-updated date will be revised.

10. Governing law

These terms are governed by the laws of Japan.

11. Contact

Questions about these terms can be sent to the address on the support page.