Information We Collect

When you sign in with your Google account, this service collects:

• Email address
• Name
• Profile image
• Google account identifier (sub claim)

When you connect Notion, your Notion workspace access token, workspace name, and duplicated database ID are stored in Vercel KV (Upstash Redis).

How We Use Information

We use the collected information only for the following purposes:

• Authentication into this service
• Reading and writing book data in your Notion workspace
• Improving this service via anonymous usage analytics (below)

Cookies

We use cookies with the HttpOnly attribute for session management. The cookie contains a JWT session token issued by NextAuth.js. You can delete or block cookies from your browser settings, but some features may stop working.

Analytics

We use Vercel Analytics to improve this service. Vercel Analytics does not collect personally identifiable information; it only collects anonymous metrics such as page views.

Third Parties

We do not provide your information to third parties. However, the following infrastructure providers store or process data as required to operate the service:

• Vercel Inc. (hosting, logs)
• Upstash Inc. (Vercel KV backend)
• Google LLC (OAuth authentication)
• Notion Labs, Inc. (Notion integration and data storage)

Retention and Deletion

By choosing "Disconnect Notion" in this service, you can delete the Notion connection information stored in Vercel KV. Book data inside your Notion workspace must be deleted by you in Notion directly.

Session information tied to your Google account is discarded when you sign out or clear your browser cookies.

Affiliate Program

This site is a participant in the Amazon Associates Program, an affiliate advertising program designed to provide a means for sites to earn referral fees by advertising and linking to Amazon.co.jp.

The "Buy on Amazon" button on each book card is an affiliate link. If you make a purchase after clicking it, the site operator may receive a referral fee.

Security

Communications are encrypted via HTTPS. Server-side credentials rely on encryption-at-rest provided by the hosting vendor. We have applied security headers, input validation, rate limiting, and other measures based on the IPA "How to Secure Your Website" guidelines.

Damages from Service Use

The site operator assumes no liability for any damages or disadvantages arising from your use of this service, including but not limited to:

• Damages from using or being unable to use this service
• Damages from acting on information obtained from this service
• Mis-registration, mis-update, or loss of Notion workspace data
• Effects of service interruption, termination, or specification changes
• Issues caused by specification changes or outages of third-party services (Notion, Google, Amazon, Rakuten, etc.)

Accuracy of Information

Book information is obtained from an external API (Rakuten Books). We do not guarantee its accuracy, completeness, or freshness. Please verify the final information on the seller site (Amazon, etc.) before purchasing.

External Links

This service provides links to external sites (Amazon, Notion, Rakuten Books, etc.). The site operator assumes no responsibility for the content, services, or transactions on these external sites.

Service Changes and Termination

This service may add, change, remove features, or interrupt and terminate the service without notice. The site operator assumes no liability for any damages associated with such changes.

Copyright

Cover images and book metadata displayed in this service are the property of their respective rights holders. We use them only for the purpose of displaying bibliographic information.