Privacy Policy
Last updated: September 28, 2026
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Overview
21 Trainer ("the App") is an educational blackjack strategy training application developed by 21Trainer ("we," "us," or "our"). It is available for iPhone and iPad on the Apple App Store, and for Android on Google Play. This Privacy Policy explains how the App handles information on both platforms.
The short version: The App has no accounts, no sign-in, and no ads, and neither platform includes a crash-reporting SDK. On iPhone and iPad, the App includes Google Analytics for Firebase, which automatically collects limited usage statistics, and Meta's Facebook SDK, which tells Meta about installs, app opens, and purchases so we can measure our ads on Facebook and Instagram; Android includes neither. Your training history and settings stay on your device. On iPhone and iPad, the App contacts a small number of Apple, Google, and Meta services (listed below) and can send the developer a short technical notification when you install the App or start or change a purchase (see Developer Notifications). On Android, the App sends the developer nothing and makes no network requests of its own beyond Google Play's billing and review services.
Information We Collect
The App never asks for or collects your name, email address, phone number, or contacts. It has no accounts or sign-in. It does not track your location or use advertising identifiers. Neither platform includes a crash-reporting SDK. On iPhone and iPad, the App includes Google Analytics for Firebase, which automatically collects usage events, such as first open, session start, app updates, screen views, and in-app purchases, together with an app instance identifier, device model, OS version, app version, and approximate country derived from the IP address. The iPhone and iPad App also includes Meta's Facebook SDK, which sends Meta install, app open, and purchase events with basic device and app details, as described under Third-Party Services. On Android, the App includes no analytics or advertising SDK.
On iPhone and iPad, the App sends the developer short technical notifications about installs and purchase events over an encrypted connection. These notifications contain no name, email, or advertising identifier. The exact fields are listed in the Developer Notifications section.
On Android, the App does not send the developer anything. All data the App keeps stays on your device.
Data Storage
On iPhone and iPad, your training sessions, hand records, bankroll history, and daily challenges are stored in a database inside the App's private on-device storage. Your preferences and onboarding answers are stored in the system's on-device settings storage. There is no cloud sync, and this data does not leave your device.
On Android, your training history is stored in a private on-device database and your settings in the App's private on-device storage. Android Auto Backup is enabled for this data: if you have device backup turned on, Android may include it in the backup of your own Google account. That backup is handled by Google under your Google account settings; the developer cannot access it.
Purchases
On iPhone and iPad, purchases and subscriptions are processed entirely by Apple through the App Store. On Android, they are processed entirely by Google through Google Play. In both cases the App only reads the purchase status on your device to unlock the Pro features. The developer never receives your card number, payment details, or store account credentials.
For information about how each store handles payment data, see Apple's Privacy Policy and Google's Privacy Policy.
Third-Party Services
On iPhone and iPad, the App uses:
- Apple App Store (StoreKit): processes purchases and subscriptions, and shows the App Store rating prompt when it appears. Governed by Apple's Privacy Policy.
- Apple Search Ads attribution (Apple AdServices): on first launch, the App asks Apple whether the install came from an Apple Search Ads campaign, and if so receives campaign and keyword identifiers. See Apple's Privacy Policy.
- Firebase Remote Config (Google): downloads configuration values, such as which onboarding and paywall layouts to show. Fetches are delivered through Firebase Installations, which sends Google a Firebase installation identifier for your installation of the App, along with basic app details such as the app version and device language, so Google can deliver the right configuration. No training data or onboarding answers are sent to it, and the App sets no custom signals or user properties for it. See the Firebase Privacy Information.
- Google Analytics for Firebase (Google): automatically collects usage events, such as first open, session start, app updates, screen views, and in-app purchases, together with an app instance identifier, device model, OS version, app version, and approximate country derived from the IP address. We use it to understand how the App is used in aggregate. It is not used for advertising, and the App does not request tracking permission. See How Google uses information from sites or apps that use our services and the Firebase Privacy Information.
- Meta App Events (Facebook SDK, by Meta): tells Meta when the App is installed and opened, and when a purchase, subscription, or free trial completes, including the product, price, and currency. Each event carries basic device and app details, such as device model, iOS version, app version, language, and time zone, along with an identifier the SDK creates for your installation of the App. Meta also receives your IP address as part of the connection. If the SDK's own code causes the App to crash, the SDK can send Meta a report about that crash. We use this data to measure, in aggregate, how well our ads on Facebook and Instagram lead to installs and purchases. The App shows no ads, and because it never asks for tracking permission, the SDK cannot read your device's advertising identifier. Meta receives this data under Meta's Privacy Policy.
- Telegram Bot API: delivers the developer notifications described in the next section, over HTTPS to a private chat only the developer can read. See Telegram's Privacy Policy.
On Android, the App uses:
- Google Play Billing: processes purchases and subscriptions. See Google's Privacy Policy.
- Google Play In-App Review API: shows the rating prompt, handled entirely by Google. See Google's Privacy Policy.
The Android app does not use Firebase, Meta, Telegram, or any analytics, advertising, or tracking service.
Developer Notifications (iPhone and iPad)
The iPhone and iPad app can send the developer a short message through the Telegram Bot API, over HTTPS, to a private chat that only the developer can read. There is one message per event, not continuous reporting. The Android app never sends these notifications.
When they are sent: once shortly after the App is first installed; when a purchase, free-trial start, renewal, or restore completes; and when a subscription is refunded or expires. Whether they are sent at all is controlled by switches the developer manages remotely, so they can be turned on or off without an App update.
What each message can contain:
- App version and build number
- Device model and iOS version
- Country (the App Store storefront for purchase events, the device region for the install message)
- Product name and displayed price, for purchase events
- Which paywall layout was shown and where the purchase started, for purchase events
- Whether the install was attributed to an Apple Search Ads campaign, and if so the campaign, ad group, keyword, and ad identifiers
- Your onboarding answers (experience level, practice frequency, where you play, your goal, your biggest blocker, minutes per day, casino rules preset), when you answered them
- App Store transaction identifiers, for purchase events
- Whether the transaction is sandbox or production
No name, email, phone number, precise location, advertising identifier, or store account credential is ever included. These notifications are not linked to an account, because the App has no accounts.
Data Retention and Deletion
Your training history and settings are kept on your device until you delete them, and are removed when you uninstall the App.
- Reset statistics (iPhone, iPad, and Android): go to Settings in the App and tap "Reset All Statistics" to permanently delete your on-device training history. On iPhone and iPad, this deletes your training sessions, hand records, and bankroll history. The Android app has the same "Reset All Statistics" row in Settings, which deletes the same kinds of on-device training history.
- Uninstalling the App: removes the App's on-device data on both platforms. On Android, if Android Auto Backup copied that data to your Google account, managing or deleting that backup is done through your Google account's backup settings.
- Data the developer received: if you want the developer to delete any developer notification the App sent (see above), contact us through the support page and we will delete it. Purchase records held by Apple or Google are managed by those companies under your Apple ID or Google Account.
- Google Analytics for Firebase (iPhone and iPad): Google retains Analytics data according to the retention setting in the developer's Firebase project. If you want Analytics data associated with your app instance deleted, contact us through the support page and we will ask Google to delete it.
- Meta App Events (iPhone and iPad): Meta keeps this data under its own retention practices, described in Meta's Privacy Policy. If you have a Facebook or Instagram account, you can review and disconnect activity that apps share with Meta through Your activity off Meta technologies.
Children's Privacy
21 Trainer is intended for adults and is not directed at children. On the App Store it is rated 17+. We do not knowingly collect any information from children. The App contains simulated gambling content for training and educational purposes only. No real money is wagered.
Changes to This Policy
We may update this Privacy Policy from time to time. Any changes will be posted on this page with an updated "Last updated" date. We encourage you to review this page periodically.
Contact Us
If you have any questions about this Privacy Policy, please contact us:
You can reach us through our support page.
