Privacy Policy

This English text is a reference translation. The Japanese version is the authoritative text, and it prevails in the event of any discrepancy. Read the Japanese version

1. Basic Policy

Arakawa Kensuke Design (the "Operator") handles information obtained through Bunko (the "Service"), a book management service, in accordance with this Privacy Policy (this "Policy").

2. Information We Collect

Email address: Obtained from what you enter or from your Google account. It is stored only in Firebase Authentication and is not saved in the Service’s database (Firestore).
Password: Obtained from what you enter and stored by Firebase Authentication. The Operator cannot know it in plain text.
Display name, profile image, bio, and social links: Obtained from what you enter or from your Google account, and stored in Firestore.
Settings such as display language: Obtained from your selections and stored in Firestore.
Information arising from your use of the Service, such as registered books, shelves, tags, comments, public settings, archive status, and sort order, is stored in Firestore.
IP address: Obtained to prevent misuse, detect abuse of reports, and apply rate limits. Report records store only a hashed value, not the IP address itself. For rate limiting, a hashed value is kept temporarily until the time window used for the check has passed.
Browser type (User-Agent) and screen size: Obtained to reproduce problems. If you send feedback, they are saved in that record. Report records store only a hashed value.
Access time and request details: Recorded in server logs for troubleshooting and security.
If you send an inquiry: The category, message, reply email address, and display language are saved.
If you send a report: The target, reason, additional details, and information identifying the reporter (your user ID when logged in; hashes of your IP address and User-Agent when not logged in) are saved.
If you send feedback: The category, message, path of the page that was open when you sent it (excluding the query string), display language, browser type, and screen size are saved.

3. Purposes of Use

Providing and displaying the Service, and enabling its sharing features
Verifying identity and preventing misuse
Responding to inquiries and reports
Investigating and fixing problems, and improving the Service
Understanding usage (statistical analysis)
Complying with laws and regulations

4. Use of Cookies and Similar Technologies

Session cookie (__session): Used to keep you logged in. Required to use the Service.
CSRF token cookie (__csrf): Used to prevent forged requests. Required to use the Service.
Display language cookie (NEXT_LOCALE): Used to keep your chosen display language. Required to use the Service.
Analytics opt-out cookie (bunko_analytics_optout): Used to keep your setting to stop the analytics described in Section 5. It is saved only if you choose to stop analytics, and it contains no information that identifies you.
The Service does not use cookies for advertising or behavioral targeting. The analytics described in Section 5 do not use cookies to identify users.

5. External Transmission (Transmission of User Information to External Parties)

To understand how the Service is used, the Service uses analytics provided by PostHog (PostHog Inc.), and information is sent from your device to an external party as follows.
Recipient: PostHog Inc. (servers in its European region). Transmission passes through a path under the Service’s own domain (/ingest).
Information sent: URLs of pages viewed, referrer, browser type, screen size, interactions such as clicks, IP address, and, while you are logged in, your user ID.
Purpose of sending: Statistical understanding of usage, and informing decisions about improving features.
Storage on your device: The Service does not store cookies or identifiers on your device for analytics (information used for analytics is held only in memory and disappears when you close the page). However, if you stop analytics using the method below, and only in that case, a cookie that keeps that setting is saved (Section 4).
How to stop: Log in and turn it off under "Analytics" on the settings screen (/settings). The setting is saved to your account and applied to your device each time you log in. While you are not logged in, it is effective only on the device (browser) on which you set it.
Bibliographic information and book covers are retrieved by the Service’s servers, so no information is sent from your device to external bibliographic services (see the end of Section 7).

6. Provision to Third Parties

The Operator does not provide the information it obtains to third parties, except in the following cases.
Where you have consented
Where required by laws and regulations
Where it is necessary to protect the life, body, or property of a person and it is difficult to obtain the consent of the person concerned

7. Contractors and Storage Locations

Google (Firebase / Google Cloud): The Operator entrusts authentication, databases, file storage, and running the application to a business operator in Japan (Google Cloud Japan G.K.). Databases and files are stored in Japan (asia-northeast1).
PostHog Inc. (United States): The Operator entrusts analytics to this business operator. Data is stored in Europe.
Email delivery provider: The Operator entrusts the delivery of verification codes and notification emails to this business operator. Data is stored in the United States.
Through its contracts with contractors, the Operator sets out the scope of handling of personal data and the obligation to take security measures, and exercises necessary and appropriate supervision over its contractors.
The bases for providing personal data to business operators in foreign countries are as follows.
PostHog Inc. (a U.S. corporation; data stored in Europe): Personal data is provided to a business operator that continuously maintains a system conforming to the standards prescribed in Article 16 of the Enforcement Regulations of the Act on the Protection of Personal Information.
Email delivery provider (United States): Personal data is provided to a business operator that continuously maintains a system conforming to the standards prescribed in Article 16 of the Enforcement Regulations of the Act on the Protection of Personal Information.
For business operators to which personal data is provided on the basis of such a conforming system, the Operator takes the measures necessary to ensure the continuous implementation of equivalent measures. Information on the measures taken will be provided upon request through the support desk.
To retrieve bibliographic information and book covers, the Service’s servers send queries to the Google Books API, openBD, Rakuten Books, and the National Diet Library Search, but no information that can identify users is sent (only search terms and book identifiers are sent).

8. Retention Periods

Account information and User Content: Permanently deleted 30 days after withdrawal.
Inquiry records (including reply email addresses): Kept for one year after the inquiry has been handled.
Report records: Kept as a record of how reports were handled (information identifying the reporter is kept only as hashed values).
Feedback records: When the account is permanently deleted after withdrawal, the sender’s user ID is detached, and the message is kept as a record for improvement.
Operational audit records: Kept as a record of measures taken (they contain no information about reporters or people who sent inquiries).
Even after withdrawal, inquiry records are kept for the period set out above. This is because the course of handling must remain verifiable after the other party has withdrawn, for example in claims of rights infringement or objections to measures.

9. Requests for Disclosure, Correction, and Suspension of Use

If you wish to request disclosure, correction, addition, deletion, or suspension of use of retained personal data, please contact the Operator through the support desk. After verifying your identity, the Operator will respond in accordance with applicable laws and regulations.
Account information and User Content can also be deleted without a request, by withdrawing from the Service on the settings screen.

10. Security Measures

Communications are encrypted using TLS.
Direct writes to the database are prohibited, and data is updated only through paths that have passed server-side authorization.
Administrative functions can be operated only by users with the relevant permissions, and records of those operations are kept.
Passwords are managed in a form the Operator cannot know (Firebase Authentication).
When personal data is stored in a foreign country, the Operator takes necessary and appropriate security measures after understanding that country’s systems for the protection of personal information. Storage locations are as set out in Section 7.

11. Use by Minors

Persons under 13 years of age may not use the Service.
Persons under 18 years of age must obtain the consent of a person with parental authority or another legal representative before using the Service.

12. Changes to This Policy

This Policy may be changed. Where important changes are made, they will be announced on the Service.
The revision history is published on this page.

13. Operator’s Name and Address, and Contact

Please send inquiries and complaints about this Policy and the handling of retained personal data through the Service’s support desk.
The Operator’s name and address will be provided without delay upon request through the support desk.