Terms of Use

Agreeing to these terms

By using the Mahjong Sensei iOS app, this website, or the game you can play in your browser, you agree to these Terms. If you do not agree, please do not use them. In these Terms, "we" and "us" mean Lumio Data Labs.

Licence to use the app

The iOS app is licensed, not sold, to you. Your licence is Apple's Licensed Application End User Licence Agreement, which applies to every app distributed through the App Store without a custom agreement. These Terms sit alongside it and cover the things it does not. Where these Terms and Apple's agreement genuinely conflict about the app itself, Apple's agreement governs.

The browser game on this site is provided free of charge for you to try, with no licence fee and no account.

Sensei Pro

Most of Mahjong Sensei is free, including camera tile scanning, Hong Kong faan scoring, the tile guide and practice matches. Sensei Pro is an optional purchase that unlocks the live-tile Tracker and the toughest practice opponents.

Sensei Pro is offered in three shapes, and the current prices are shown to you before you buy:

• an auto-renewing monthly subscription;
• an auto-renewing yearly subscription;
• a one-off lifetime purchase, which does not renew and has nothing to cancel.

Free trial

A 7-day free trial is available on the subscriptions. If you cancel before the trial ends you are not charged. As Apple requires us to note: if you buy a subscription while a free trial is still running, the unused part of the trial is forfeited.

Automatic renewal

Subscriptions renew automatically. Payment is charged to your Apple Account when you confirm the purchase, and again at the start of each new period unless you cancel. A subscription renews unless you turn off automatic renewal at least 24 hours before the end of the current period, and your account is charged for renewal within 24 hours before the period ends.

Managing and cancelling

You manage and cancel subscriptions in your Apple Account settings, not through us —Apple explains how here. Deleting the app does not cancel a subscription. Because purchases are anonymous and there is no account, use Restore purchases in the app to recover a purchase on a new device.

Refunds

Apple sells the app and handles all billing, so refunds are requested from Apple, not from us. We cannot issue a refund for an App Store purchase. If something is broken, write to us anyway — we would like to fix it.

Games you contribute

In the browser game you may choose to contribute your finished matches to help train the AI. It is off unless you switch it on. By switching it on, you grant us a non-exclusive, worldwide, royalty-free licence to use the game records you send us to train, evaluate and improve Mahjong Sensei.

We do not sell contributed games or pass them to anyone else, and you can ask us to delete yours at any time. See the Privacy Policy for exactly what a contribution contains and how to have it removed.

Using it reasonably

Please do not attempt to break, overload or gain unauthorised access to the site or its services; submit fabricated or automated game data; or use Mahjong Sensei to break the law. We may withdraw access to the contribution service if it is abused.

What belongs to whom

The Mahjong Sensei name, the app, this site, the artwork, the trained models and the code belong toLumio Data Labs. © 2026 Lumio Data Labs. The rules of mahjong are nobody's property, and nothing here claims otherwise.

No warranty

Mahjong Sensei is provided "as is". We work hard to make the scoring and coaching correct, but mahjong is played with local variations and house rules, and the app's advice is guidance, not a guarantee. It is not a substitute for agreement between the players at your table, and we do not warrant that it will be uninterrupted or error-free.

Limitation of liability

To the fullest extent permitted by law, Lumio Data Labs is not liable for indirect, incidental, special or consequential losses arising from your use of Mahjong Sensei. Nothing in these Terms limits any liability that cannot be limited by law, including under consumer protection legislation that applies to you. Where liability cannot be excluded, it is limited to the amount you paid us for Mahjong Sensei in the 12 months before the claim.

Governing law

These Terms are governed by the laws of the Province of Ontario and the federal laws of Canada applicable therein, and the courts of Ontario have non-exclusive jurisdiction. If you are a consumer, this does not deprive you of the protection of the mandatory laws of the country you live in.

Changes

We may update these Terms. The date at the top of the page shows when they last changed, and continuing to use Mahjong Sensei after a change means you accept the updated Terms.

Contact

Lumio Data Labs · support@lumiodatalabs.com · see also Support and the Privacy Policy.