Privacy Policy
Overview
By The Book: Blackjack Trainer ("the App," "we," "our," or "us") is a blackjack basic strategy training application available on iOS and as a web application. The App uses a spaced repetition algorithm to help users learn and memorize optimal blackjack decisions.
This Privacy Policy explains what information is collected when you use the App, how that information is used, and your choices regarding that information. By using the App, you agree to the practices described in this policy.
Short version: By The Book does not collect, store, or transmit any personally identifiable information to our servers. The only data that leaves your device is what Google AdMob collects for advertising purposes (which you can prevent by purchasing the Remove Ads upgrade).
Information We Collect
We collect the minimum information necessary to provide the App's functionality. Here is a complete breakdown:
| Data Type | What It Is | Where Stored | Shared? |
|---|---|---|---|
| Game Settings | Enabled hand categories, game rules, gesture preferences | Device Only | Never |
| Review History | FSRS scheduling data per hand (stability, success/failure counts, review dates) | Device Only | Never |
| Game Statistics | Total hands played, correct/incorrect count, streak, last play date | Device Only | Never |
| Mistake Log | Record of hands played against basic strategy and their outcomes (W/L/P) | Device Only | Never |
| Tutorial Status | Whether the first-time tutorial has been completed | Device Only | Never |
| Purchase Status | Whether the Remove Ads in-app purchase has been made | Device Only | Never |
| Advertising ID (IDFA) | Apple's Identifier for Advertisers, used by Google AdMob | Google AdMob | Google only (see §4) |
| Personal Information | Name, email, phone, location, contacts — none of these | Not Collected | Never |
Local Data Storage
All game data is stored exclusively on your device using the browser's
localStorage API (web) or the equivalent on iOS via Capacitor's local storage
bridge. This data never leaves your device and is never transmitted to any server operated
by us.
The following keys are stored in local storage:
- blackjack-settings — Game configuration (categories, rules, gesture toggles)
- blackjack-game-stats — Lifetime accuracy, streak, and session statistics
- blackjack-review-histories — FSRS spaced repetition data for each hand situation
- blackjack-tutorial-status — First-time tutorial completion flag
- blackjack-purchase-status — Remove Ads purchase verification flag
- blackjack-mistake-records — Win/loss log for hands played against basic strategy
You can delete all of this data at any time by using the "Reset All Progress" button in the app's Settings tab, or by clearing your browser's local storage, or by deleting and reinstalling the iOS app.
Advertising & Third Parties
The free version of By The Book displays advertisements served by Google AdMob, a third-party advertising platform operated by Google LLC. AdMob may collect and use certain data from your device to serve personalized or contextual advertisements.
Data that Google AdMob may collect includes:
- Apple's Identifier for Advertisers (IDFA / ASIdentifierManager)
- IP address (used for approximate geographic targeting)
- Device type, operating system version, and screen size
- App usage interactions relevant to ad delivery and measurement
- Crash reports and performance diagnostics
Google AdMob's data practices are governed by Google's Privacy Policy and Google AdMob's Data Safety information. We are not responsible for Google's data collection practices.
On iOS, you will be asked for permission to track your activity across apps and websites (App Tracking Transparency prompt). You may deny this permission; the App will continue to function and ads will be served on a non-personalized basis.
Removing ads: You can permanently remove all advertising from the App by purchasing the "Remove Ads" upgrade (see §5). Once purchased, no AdMob SDK calls are made and no advertising-related data is collected.
We do not use any other third-party SDKs, analytics platforms, crash reporters, or tracking libraries beyond Google AdMob.
In-App Purchases
By The Book offers a single in-app purchase: Remove Ads, a one-time non-consumable purchase that permanently disables all advertisements.
In-app purchases are processed entirely by Apple's App Store / StoreKit. We do not collect, store, or process any payment card information or billing details. Apple handles all aspects of the transaction.
Upon successful purchase, we store a local flag (blackjack-purchase-status)
on your device to remember that ads have been removed. This flag contains no payment
information. Apple's receipt validation is used to verify purchases; this process is
handled by Apple and does not involve our servers.
For questions about your purchase, refunds, or billing, please contact Apple Support at support.apple.com.
Analytics
By The Book does not use any analytics platform (such as Firebase Analytics, Mixpanel, Amplitude, or similar services). We do not track screen views, feature usage events, or user journeys.
The only usage data that may be collected is what Apple gathers through the App Store (aggregate crash reports and download statistics), which is subject to Apple's Privacy Policy.
Children's Privacy
By The Book: Blackjack Trainer is rated 17+ on the Apple App Store due to its gambling-themed content (simulated card play). The App is not intended for use by anyone under the age of 17.
We do not knowingly collect any personal information from children under 13 (or the applicable age of digital consent in your jurisdiction). Since the App does not collect any personal information from any user, this requirement is satisfied by design.
If you are a parent or guardian and believe your child has used this App, please be aware that no personal data has been collected. You may contact us at the address below with any concerns.
Data Retention & Deletion
Because all data is stored locally on your device, you have complete control over its retention and deletion:
- In-app reset: Open the App → Stats & Settings → Settings tab → scroll to the "Data" section → tap "Reset All Progress." This erases all game history, review data, and statistics from your device.
- App deletion (iOS): Deleting the app from your iPhone removes all associated local storage data.
- Browser (web version): Clear your browser's local storage or site data for bjbythebook.com to remove all stored data.
Since we hold no data on our servers, there is nothing to request deletion of from us directly. All data lives only on your device.
Security
Because By The Book does not transmit personal data to any server, the attack surface is minimal. Game data stored in local storage is protected by the device's operating system sandbox — other apps cannot access it.
The web version is served over HTTPS, ensuring that the application code and assets are delivered securely. We recommend keeping your device's operating system and the App up to date to benefit from the latest security improvements.
Your Rights
Depending on your location, you may have certain rights regarding your personal data. Because By The Book does not collect or process personal data on our servers, most of these rights are satisfied by the App's privacy-by-design architecture. Nonetheless:
- Right to access: All data the App uses is already visible to you — it is stored directly on your device in your browser's local storage.
- Right to deletion: You can delete all data at any time as described in §8 above.
- Right to opt out of personalized advertising: On iOS, deny the App Tracking Transparency (ATT) prompt, or go to Settings → Privacy & Security → Tracking and disable tracking for By The Book.
- California residents (CCPA): We do not sell personal information. The "Do Not Sell or Share My Personal Information" right does not apply as no personal information is sold.
- European residents (GDPR): Our legal basis for any data processing is your consent (ATT prompt for advertising) or legitimate interest (local-only game data for core functionality). You may withdraw consent at any time via iOS Settings.
Changes to This Policy
We may update this Privacy Policy from time to time to reflect changes in the App's functionality, applicable laws, or our practices. When we make material changes, we will update the "Last updated" date at the top of this page and, where appropriate, post a notice in the App.
We encourage you to review this policy periodically. Continued use of the App after any changes constitutes your acceptance of the updated policy.
Contact Us
If you have any questions, concerns, or requests regarding this Privacy Policy or the App's data practices, please reach out: