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Mahjong Monsters Privacy Policy
Effective date: September 19, 2026 / Last updated: October 24, 2026 (the App no longer creates an anonymous identifier when loading a transfer code)
Pocosoft Inc. ("we", "us") sets out below how information is handled in our smartphone game "Mahjong Monsters" for iOS and Android (the "App").
1. Basic principle — we run no server
The App does not use any server operated by us. Your save data, the monsters and items you own, your settings, and the player name you enter at first launch are stored on your device. A copy of your save data may also be stored in iCloud on iOS or Android Auto Backup. Encrypted save data is stored temporarily when you create a transfer code, and some gameplay activity is measured to improve the game (Sections 2 and 4). We do not collect information through the App that directly identifies you, such as your name, email address, phone number, or postal address.
However, the App relies on the third-party services listed below, and the providers of those services obtain certain information from your device. What is obtained, and why, is described in the following sections.
2. Save data backup
- iOS: A copy of your save data is stored in iCloud (Key-Value Store) under your own Apple ID. This is your iCloud storage; we cannot read or obtain its contents. It is not used if you are not signed in to iCloud.
- Android: Android Auto Backup may back up your save data and settings to your own Google account. We cannot access it. Whether backups are made depends on your device settings.
- Transfer code (switching devices): Only when you tap "Get a Transfer Code", your save data is encrypted on your device and stored temporarily in Firebase (Cloud Firestore), provided by Google LLC. The encryption key is derived from the transfer code, which is never sent to us or to Google, so neither we nor Google can read the contents. The stored data is not linked to you or to any identifier, and it is deleted as soon as it is loaded on your new device. If it is never loaded, it can no longer be retrieved 10 days after it was issued, and we delete it afterwards. The App also uses Firebase App Check (Apple's App Attest and Google's Play Integrity) to confirm that requests come from the genuine App.
3. Crash and error reporting (Firebase Crashlytics)
To improve the quality of the App, information about crashes and errors is sent to Firebase Crashlytics, a service provided by Google LLC.
- Information sent: device model, OS version, App version, where in the program the error occurred (stack trace), the time of the error, and device state such as free memory.
- Purpose: used only to identify and fix bugs.
- This does not include information that identifies you personally, your player name, or your game progress. It is not used for advertising.
- See Privacy and Security in Firebase for how Firebase handles data.
4. Gameplay analytics (Google Firebase Analytics)
In release builds, the App sends usage information to Firebase Analytics, provided by Google LLC, to improve the game and its balance.
- Information sent: stages played, the times a stage starts and ends, wins, losses and retreats, battle duration, invalid moves and skill uses, deck cost, highest rarity and average level, player rank, stamina and sortie cost, evolution target and whether paid forced evolution was used, and actions such as rank-ups. This also includes app launch and usage information automatically recorded by Firebase Analytics, device model, OS and App version, approximate region, and an identifier for this installation of the App.
- Purpose: we aggregate how long stages take and where players encounter difficulty to improve the game. We do not use this data to target ads or track individuals.
- Analytics events do not include your player name, email address, transfer code, your complete save data file, or advertising IDs (IDFA on iOS or Advertising ID on Android). Some values from your save data, including rank and stamina, are sent as described above. We do not use this data to identify you personally. Firebase Analytics does use an app installation identifier to associate events from the same installation.
- See Privacy and Security in Firebase for how Firebase handles data.
5. Advertising (Google AdMob)
The App may show a full-screen (interstitial) advertisement after you close the battle result screen. Ads are served by Google AdMob, a service provided by Google LLC.
- Information Google obtains to serve ads: advertising identifiers (Android Advertising ID, iOS IDFA), device type and OS version, approximate region inferred from your IP address, and how the App is used. See How Google uses information from sites or apps that use its services for details.
- IDFA on iOS: On iOS the App asks for permission to track you (App Tracking Transparency). Your IDFA is used for ads only if you allow it. You can play the game normally without allowing it.
- Users in the EEA, the UK and Switzerland: As required by law, the App shows a consent screen about the use of your data for advertising. You can change your choices at any time.
- Removing ads: Purchasing the in-app product "Remove Ads" stops the ads after battles.
- For the list of Google's advertising partners, see Ad technology providers in AdMob.
6. In-app purchases
The App offers two in-app purchases: Remove Ads (one-time) and Forced Evolution (consumable).
- All payments are processed by Apple (App Store) or Google (Google Play). We never receive your payment details such as credit card numbers.
- The only information we receive on your device is which product was purchased, and the resulting entitlement (ad removal, forced evolution tickets) is stored on your device.
- The one-time product can be regained with "Restore Purchases" using the same store account. Consumable products are not restored.
- For how each store handles payment information, see the Apple Privacy Policy and the Google Privacy Policy.
7. Summary of information obtained
| Information | Obtained by | Purpose |
|---|
| Complete save data file, player name, settings | Your device (except for the backup and transfer described in Section 2). Some values, including rank and stamina, are measured as described in Section 4 | Continuing the game |
| Copy of save data | Apple (iCloud) / Google (Auto Backup), under your own account | Restoring on a new device or after reinstalling |
| Encrypted save data (only when you get a transfer code; retrievable for 10 days), plus information for verifying the App | Google (Firebase Cloud Firestore and App Check). Neither we nor Google can read the contents | Carrying your save over to a new device |
| Device model, OS and App version, error location | Google (Firebase Crashlytics) | Fixing bugs |
| Stages played, duration, results and other usage data; device and App information; an app installation identifier | Google (Firebase Analytics); we use aggregated results | Improving the game |
| Advertising identifier, device information, approximate region | Google (AdMob) and its advertising partners | Serving and measuring ads |
| Purchase completion | Apple / Google (payment), your device (entitlement) | In-app purchases |
| What you write on the contact form (reply-to email address, type of enquiry, message, and optionally your device, OS and App version) | Us, and Google (Google Forms) | Replying to your enquiry |
8. Sharing with third parties
We do not sell your information. Using the external services described in this policy sends information to Google and Apple. Each provider handles that information under its own privacy policy.
9. Children
The App is not directed at children under 13, and we do not knowingly collect personal information from children under 13.
10. Your choices
- Ad personalization: You can limit or reset the use of your advertising identifier in Settings → Privacy & Security → Tracking on iOS, or Settings → Google → Ads on Android.
- Deleting your data: You can delete your save data from "Erase Data" inside the App (on iOS this also deletes the copy in iCloud). Uninstalling the App also removes the data stored on your device.
- Deletion requests: For the data we hold (the save data held for a transfer code, and what you send us through the contact form), you can request deletion from "Deleting your data" on the contact page, which also lists what is deleted and how long each kind of data is kept.
11. Changes to this policy
We may revise this policy when laws change or the App's features change. Revisions are posted on this page, and depending on the content the App may ask for your consent again at launch.
12. Contact
For questions about this policy or how information is handled in the App, please use our contact page.
Enquiries reach us through Google Forms, provided by Google LLC. The reply-to email address, type of enquiry and message you enter, together with the device, OS and App version if you choose to give them, are sent to us through that form. We use them only to reply to your enquiry, never for advertising. You do not need to sign in to a Google account to use the form, and we do not receive your account details even if you are signed in. For how Google handles data, see the Google Privacy Policy.
Pocosoft Inc.