Privacy Policy

This Privacy Policy explains how QMaths ("we", "us") collects, uses and protects your information in the Blackbook: English Vocabulary mobile app and the website blackbook.qmaths.in (together, the "Service"). By using the Service you agree to this policy.

1. Information we collect

Account information (when you sign in)

• Google Sign-In: your name, email address and profile photo, as provided by Google.
• Truecaller (optional): if you choose to verify your phone, your phone number and name via Truecaller's secure server-side verification. You can use the app fully without Truecaller.

Learning & usage data

• Quiz attempts, answers, scores, progress, mastery and streaks, to personalise practice and show your performance.
• Which sections, words and features you use, to improve the app.
• Redeem / book-verification codes you submit, to grant access you are entitled to.

Device & diagnostic data

• App version, device model, OS version, language and network state.
• Anonymous crash and error diagnostics. Sensitive values (email, phone, tokens, codes) are never stored in diagnostic logs, only salted irreversible hashes or generic markers.

We do not collect your contacts, SMS or precise location.

2. How we use your information

• To create and secure your account and sign you in.
• To save your progress and personalise quizzes, revision and feedback.
• To operate, maintain, debug and improve the Service.
• To prevent abuse, fraud and unauthorised access.

3. The camera permission

The app requests camera access only when you choose to scan a QR / book code. Camera hardware is optional and the app works without it. We do not record or store images.

4. Third-party services

We use a small number of trusted providers that process limited data on our behalf:

• Google - Sign-In, Firebase Crashlytics (crash reports) and Firebase Analytics (aggregate usage).
• Truecaller - optional phone verification, only if you initiate it.
• Google AdMob - the app includes the Google Mobile Ads SDK to show optional, reward-based video ads (for example, watching a short ad to unlock an extra quiz). When ads are shown, Google may collect your device's advertising ID and related device signals to serve and measure ads, as described in Google's advertising policy. We never show banner or forced ads, and ads are always user-initiated. You can reset or delete your advertising ID anytime in Android Settings > Privacy > Ads.

These providers have their own privacy policies. We do not sell your personal data to anyone.

5. Data retention

• Account and learning data: kept while your account is active.
• Diagnostic logs: rotated and retained for a short period (about 30 days), then deleted.
• On account deletion, your personal data is removed as described in our Data Deletion policy.

6. Security

Authentication tokens are stored in the device's secure keystore. Traffic uses HTTPS. Content APIs require authentication and are rate-limited. No method is 100% secure, but we work to protect your data.

7. Children

The Service is intended for competitive-exam aspirants aged 13 and above. We do not knowingly collect personal data from children under 13. If you are under 18, please use the Service with the knowledge and consent of a parent or guardian; by permitting a minor to use the Service, the parent/guardian consents to the processing of the minor's personal data as described in this policy. A parent or guardian may request deletion of a minor's data at any time via our contact form or [email protected].

8. Your rights

You can access, correct or delete your data. To delete your account and associated data, see Delete your data or email us.

9. Changes

We may update this policy. Material changes will be reflected here with a new "Last updated" date.

10. Contact