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, payment identifier and subscription status of a purchase or subscription.
- 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), and usage statistics via Google Analytics (GA4), which uses cookies. We do not send directly identifying information such as your name or email address.
- Feedback: What you enter in the feedback form (a Google Form), the page it relates to, and an optional email address for a reply. We do not require you to sign in or to submit your Google account email address.
- Traffic source category: The referrer of your first visit, reduced to a predefined category such as “search” or “social” (we do not store the URL or search terms themselves). It is stored in browser storage and attached to the payment record when you buy paid content, so that we can see which route a purchase came from. In the European Economic Area and the United Kingdom, it is stored only after consent.
2. Purposes of use
- Providing the Service, authenticating users and managing purchase entitlements
- Saving and displaying learning progress
- Responding to inquiries
- Reviewing feedback we receive and considering improvements to questions and features
- 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. |
| Google LLC | Access analytics (Google Analytics) and receiving feedback (Google Forms) | 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.
Information transmitted to external services
For analytics purposes, the Service transmits the following information from your device to external providers.
| Recipient | Information transmitted | Purpose |
|---|
| Cloudflare, Inc. | Pages viewed, referrer, approximate region, browser type (no cookies) | Understanding and improving how the site is used |
| Google LLC | Pages viewed, referrer, approximate region, browser type, the identifier stored in Google Analytics cookies, and the interaction events we send (revealing an explanation, starting or completing a purchase) | Understanding and improving how the site is used |
Google Analytics uses cookies to collect this information. See the
Google Privacy Policy
for how Google handles it. You can refuse collection or withdraw consent at any time through “Analytics settings”
at the bottom of every page. On withdrawal, we delete Google Analytics cookies accessible to this Service and the
stored traffic-source category. For visits from the European Economic Area and the United Kingdom, Google Analytics
cookies and the traffic-source category are stored only with your 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 and subscription records (payment identifier, amount, date, subscription status) may be retained in anonymized form that cannot identify an individual, based on legal retention obligations and accounting needs.
- Feedback form responses are retained within Google Forms for as long as needed to operate the form and consider improvements to questions and features. We do not create a separate record of responses.
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 support@sqlquizbook.com. Use the same address if you would like something you submitted through the feedback form to be deleted.
7. Revisions
If this policy is revised, we will announce it on this page.
Enacted: 2026-07-12