← Back

Privacy Policy

Last updated: March 19, 2026

1. Information We Collect

When you use this Service, we may collect the following information:

  • Purchase information: Email address and license key (provided through Gumroad at the time of purchase).
  • Device information: A browser-generated device fingerprint (derived from screen resolution, timezone, browser language, and hardware concurrency) used solely for license activation and enforcement. This fingerprint is only generated after you consent.
  • Usage data: IP address and user agent string, collected during license activation and verification.
  • Study progress: Quiz scores and progress data stored locally in your browser (localStorage). This data never leaves your device.

2. Lawful Basis for Processing

We process your data under the following legal bases (GDPR Article 6):

  • Contractual necessity: Processing your license key and activation data is necessary to fulfill our contract with you (delivering the product you purchased).
  • Consent: Device fingerprinting for license enforcement is performed only with your explicit consent, which you may withdraw at any time.
  • Legitimate interest: IP address logging during activation to prevent fraud and abuse.

3. How We Use Your Information

We use the information we collect to:

  • Verify and activate your license key.
  • Enforce the device activation limit (3 devices per license).
  • Provide customer support.
  • Prevent fraud and abuse.

We do not use your data for advertising, profiling, or marketing purposes.

4. Data Storage and Security

License and activation data is stored in a server-side database. We use reasonable security measures to protect your data, including rate limiting, secure headers, and encrypted connections.

5. Third-Party Services

This Service uses the following third-party services:

  • Gumroad: Processes payments and manages license keys. Gumroad's privacy policy governs information collected during purchase. See Gumroad's Privacy Policy.
  • Google Fonts: Web fonts are loaded from Google's servers (fonts.googleapis.com). When you visit this site, your browser sends your IP address to Google to retrieve font files. See Google's Privacy Policy.

6. Data Sharing

We do not sell, rent, or share your personal information with third parties, except as required by law or to protect our legal rights.

7. Data Retention

We retain your license and activation data for as long as your license is active. IP addresses stored during activation are retained for up to 12 months for fraud prevention purposes and then deleted. If you request deletion of your data, contact us and we will remove your records within 30 days.

8. Your Rights (GDPR)

If you are located in the European Economic Area (EEA) or the United Kingdom, you have the right to:

  • Access the personal data we hold about you.
  • Request correction or deletion of your data.
  • Object to or restrict processing of your data.
  • Request portability of your data in a machine-readable format.
  • Withdraw consent at any time (where processing is based on consent).
  • Lodge a complaint with your local data protection authority.

9. Your Rights (California / CCPA)

If you are a California resident, under the California Consumer Privacy Act (CCPA/CPRA) you have the right to:

  • Know what personal information we collect, use, and disclose about you.
  • Request deletion of your personal information.
  • Opt out of the sale or sharing of your personal information. We do not sell or share your personal information as defined by the CCPA.
  • Not be discriminated against for exercising your privacy rights.

To exercise any of these rights, contact us at the email address listed below.

10. Cookies and Local Storage

This Service uses browser localStorage to save your study progress and license status. We do not use tracking cookies or third-party analytics.

11. Children's Privacy

This Service is not directed at children under 13. We do not knowingly collect personal information from children under 13.

12. International Data Transfers

Your data may be processed and stored on servers located outside your country of residence. By using the Service, you acknowledge that your data may be transferred to, and processed in, countries that may not provide the same level of data protection as your home country. We take reasonable steps to ensure your data is treated securely.

13. Changes to This Policy

We may update this Privacy Policy from time to time. Continued use of the Service after changes constitutes acceptance of the revised policy.

14. Contact

For privacy-related questions, data requests, or to exercise any of your rights, contact us at:

  • Email: [[email protected]]
  • Or through our Gumroad store page.

Terms of Use · Privacy Policy

© 2026 Jack. All rights reserved.