Privacy Policy
This is a reference English translation. The Japanese version is authoritative; if there is any discrepancy, the Japanese version prevails.
This policy sets out how personal information is handled in SQL Quiz Book (https://sqlquizbook.com/, the “Service”).
1. Information we collect
- Account information: When you sign in with a Google or GitHub account, we receive information provided by each authentication provider, such as your email address, name and profile image URL. We do not collect or store passwords.
- Purchase information: Payment details (such as card numbers) for paid content are collected directly by our payment processor, Stripe, Inc.; the Service does not hold card numbers. The Service records the date, amount and payment identifier of a purchase.
- Learning records: Learning progress such as completion checks (stored on the server when signed in, or in your browser’s localStorage when signed out).
- Access information: Anonymous usage statistics via Cloudflare Web Analytics (no cookies are used and individuals are not identified).
2. Purposes of use
- Providing the Service, authenticating users and managing purchase entitlements
- Saving and displaying learning progress
- Responding to inquiries
- Anonymous statistical analysis to improve the Service
- Preventing misuse
3. Outsourcing and provision to third parties
| Provider | Purpose | Location |
|---|
| Supabase, Inc. | Authentication and database (storage of accounts / purchase entitlements / learning records) | United States, etc. |
| Stripe, Inc. | Payment processing | United States, etc. |
| Cloudflare, Inc. | Content delivery and anonymous access analytics | United States, etc. |
Each of the above is an entrustment within the scope necessary to perform the service. Except as required by law, we do not provide personal information to third parties without the individual’s consent.
4. Retention and deletion
- You can delete your account at any time from the account page. On deletion, your account information and learning records are erased.
- Purchase records (payment identifier, amount, date) may be retained in anonymized form that cannot identify an individual, based on legal retention obligations and accounting needs.
5. Security
Communications are encrypted with TLS. Access to the database is restricted to the individual using row-level security and similar measures.
6. Contact
For requests to disclose, correct or delete personal information, please contact hkdocs.info@gmail.com.
7. Revisions
If this policy is revised, we will announce it on this page.
Enacted: 2026-07-12