Privacy Policy

This Privacy Policy explains what personal data we process when you use Kaizen64 (the "Service"), why, and what rights you have. We process personal data in accordance with the EU General Data Protection Regulation (GDPR).

1. Who is responsible

The controller responsible for data processing on this website is:

Jakob Pfreundt
Natruper Straße 183, 49076 Osnabrück
Germany
Email: contact@kaizen64.com

2. What data we collect

Account data. When you register, we collect your username, email address, and a password. Your password is never stored in readable form — we store only a cryptographically hashed version of it.

Progress data. When you are logged in and use the Service, we store your puzzle activity: completed puzzles and ladders, solve times, error counts, per-puzzle results, and your puzzle rating(s). This lets us save your progress, statistics, and rankings.

Data stored on your device (local storage). We store a small amount of data in your browser's local storage, including your current streak.

Technical data. When you access the Service, our server automatically processes technical information such as your IP address, browser and device type (user agent), and the date and time of access. This is used to operate the Service securely and to prevent abuse.

3. Why we use your data, and our legal basis

• To provide the Service — creating and managing your account, saving your progress, and showing your statistics and rankings.
  Legal basis: performance of a contract / provision of a service you requested (Art. 6(1)(b) GDPR).
• To keep the Service secure and working — server logs, abuse prevention, and technical operation.
  Legal basis: our legitimate interests in a secure, functioning service (Art. 6(1)(f) GDPR).
• Essential session cookie and local storage — needed to keep you logged in and to run core features you have requested.
  Legal basis: strictly necessary storage (Art. 6(1)(b) GDPR; § 25(2) TDDDG).

4. Cookies and local storage

We use a session cookie to keep you logged in, and local storage for the features described above (streak, pre-login results). These are strictly necessary to provide the Service and do not require consent.

We do not use advertising cookies or third-party tracking.

5. Who we share data with

We do not sell your personal data. We share it only with service providers who process data on our behalf ("processors") and only as needed to run the Service:

• Hosting and database provider: Render Services Inc., which operates the servers and database on which the Service runs.

6. How long we keep your data

We keep your account and progress data for as long as your account exists. If you delete your account (or ask us to delete it), we delete the associated personal data, except where we are required to keep it longer by law. Technical logs are kept only for a limited period and then deleted.

7. Your rights

Under the GDPR, you have the right to:

• access the personal data we hold about you;
• have inaccurate data corrected;
• have your data deleted;
• restrict or object to certain processing;
• receive your data in a portable format;
• withdraw any consent you have given, at any time.

To exercise any of these rights, contact us at contact@kaizen64.com.

8. Right to complain

If you believe we process your data unlawfully, you have the right to lodge a complaint with a data protection supervisory authority. In Germany this is the authority of the federal state in which you live or work.

9. Changes to this policy

We may update this Privacy Policy as the Service changes. The current version is always available on this page, with the "last updated" date above.

10. Contact

For any questions about this Privacy Policy or your data, contact:
contact@kaizen64.com