Legal

Privacy Policy

Last Updated: August 21, 2026  |  Language: English (Authoritative Version)

1. Introduction

This Privacy Policy governs the collection, use, storage, and disclosure of personal data by David BPM ("we," "our," or "us") in connection with the operation of davidbpm.com and the David BPM Sudoku mobile application (collectively, the "Services"). By accessing or using the Services, you acknowledge that you have read, understood, and agree to the terms of this Privacy Policy.

This policy is written in English. The English version is the sole authoritative version. Any translations provided are for convenience only and do not create legal obligations.

2. Children's Privacy

The Services are not directed at, and are not intended for use by, children under the age of 13. We do not knowingly collect personal data from children under 13. If you are a parent or guardian and believe that your child has provided personal data to us without your consent, please contact us immediately at davidbpm55@gmail.com and we will take steps to delete such information.

3. Personal Data We Collect

We collect the following categories of personal data:

  • Email address — collected when you use the Score Your Puzzle feature, register for the Sudoku Daily Challenge, submit a contact form message, subscribe to or unsubscribe from our mailing list, or request a PDF Reload file.
  • Location data — country of residence and, for United States residents, state of residence. Collected when you register for the Sudoku Daily Challenge contest.
  • IP address — collected when you submit a PDF Reload request or interact with certain features, for the purposes of security and abuse prevention. IP addresses are automatically purged after 90 days.
  • Claim statements — a self-reported statement that you have purchased and reviewed a David BPM book on Amazon, collected when you submit a PDF Reload request. This information is provided on an honor system and is not independently verified.
  • Usage data — puzzle activity, contest participation records, solution step interactions, and contest timing data, collected to provide and improve the Services.
  • Platform data — whether you are accessing the Services via the web, iOS application, or Android application.

4. How We Use Personal Data

We use the personal data we collect for the following purposes:

  • To deliver contest registration keys and contest results via email.
  • To deliver puzzle evaluation results and solution steps via email.
  • To fulfill PDF Reload file requests and maintain records thereof.
  • To send newsletters and promotional communications to subscribers who have explicitly opted in to receive them.
  • To display contest rankings and statistics on the Sudoku Daily Results page.
  • To prevent abuse, maintain contest integrity, and enforce our Terms of Service.
  • To comply with applicable legal obligations.

5. Data Retention

We retain personal data for the following periods:

  • Contest data (contest entries, results, selected puzzles) — retained for 3 years from the date of the contest, after which it is automatically deleted. Before deletion, we email a summary history report of the affected contest data to the associated contestant.
  • Contestant records (Contestant ID and associated email address) — retained permanently as your account identifier and are not affected by the contest data retention period above.
  • PDF Reload records — retained for 3 years from the date of the request, after which they are automatically deleted.
  • IP addresses — automatically set to null after 90 days. The associated record may be retained for other purposes but the IP address itself is not retained beyond this period.
  • Email contact records — retained until you submit a deletion request. See Section 7 for information on how to exercise your rights.
  • Subscriber records — retained until you unsubscribe or submit a deletion request.

6. Data Sharing and Third-Party Service Providers

We do not sell, trade, rent, or otherwise transfer your personal data to third parties for their own commercial purposes. We engage the following trusted service providers solely to operate the Services:

  • Supabase — database storage and management.
  • Railway — application hosting and infrastructure.
  • Resend — transactional email delivery.
  • Google Analytics — anonymous, aggregated usage analytics. Google Analytics does not receive your email address or any directly identifying personal data.
  • Amazon Kindle Direct Publishing (KDP) — book sales platform. We do not share personal data with Amazon. Any purchase you make on Amazon is governed by Amazon's own privacy policy.

Each service provider is bound by contractual obligations to protect your personal data and to use it solely for the purposes for which it was disclosed.

7. Your Rights

Depending on your jurisdiction, you may have the following rights with respect to your personal data:

  • Right of access — the right to request a copy of the personal data we hold about you.
  • Right to rectification — the right to request correction of inaccurate or incomplete personal data.
  • Right to erasure — the right to request deletion of your personal data, subject to applicable legal retention obligations.
  • Right to object — the right to object to processing of your personal data for certain purposes.
  • Right to data portability — the right to receive your personal data in a structured, commonly used, machine-readable format.
  • Right to withdraw consent — where processing is based on your consent, the right to withdraw that consent at any time without affecting the lawfulness of prior processing.

To exercise any of these rights, please submit your request in writing to davidbpm55@gmail.com. We will respond to all legitimate requests within 30 days. We may request verification of your identity before processing your request.

You may also submit a deletion request using our Data Deletion Request page.

8. GDPR — European Economic Area Residents

If you are located in the European Economic Area (EEA), the United Kingdom, or Switzerland, the following additional provisions apply to you under the General Data Protection Regulation (GDPR) and applicable national data protection laws.

Legal basis for processing. We process your personal data on the following legal bases: (a) performance of a contract, where processing is necessary to deliver the Services you have requested; (b) legitimate interests, where processing is necessary for our legitimate business interests and those interests are not overridden by your rights; and (c) consent, where you have provided explicit consent to receive marketing communications.

Data transfers. Your personal data may be transferred to and processed in countries outside the EEA, including the United States, where our service providers operate. We take appropriate safeguards to ensure that such transfers comply with applicable data protection law.

Right to lodge a complaint. You have the right to lodge a complaint with your local data protection supervisory authority if you believe that our processing of your personal data violates applicable law.

9. Cookies and Session Storage

The Services use browser session storage to maintain your language preference and contest session data. Session storage data is not transmitted to our servers and is cleared when you close your browser session.

We use Google Analytics, which sets cookies to collect anonymous, aggregated data about how visitors use the Services. You may opt out of Google Analytics tracking by installing the Google Analytics Opt-out Browser Add-on.

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

10. Security

We implement reasonable technical and organizational measures to protect your personal data against unauthorized access, disclosure, alteration, or destruction. However, no method of transmission over the internet or method of electronic storage is completely secure, and we cannot guarantee absolute security.

11. Changes to This Policy

We reserve the right to update this Privacy Policy at any time. When we make material changes, we will update the "Last Updated" date at the top of this page. Your continued use of the Services following the posting of changes constitutes your acceptance of the revised Privacy Policy.

12. Contact

All privacy-related inquiries, data subject requests, and complaints should be directed to:

David BPM
Email: davidbpm55@gmail.com
Website: davidbpm.com/contact