Spine — Privacy Policy

Last updated: September 2026

Spine is a personal book-library app. This page explains what information Spine collects and how it's used.

Information we collect

Account info: your email address (for email/password sign-in), or your name, email, and profile photo if you sign in with Google.
Library data: the books you add — title, author, genre, and how you added them (manual entry, shelf photo, or Kindle screenshot).
Photos you upload: shelf photos or Kindle screenshots you choose to upload for book detection. These are sent to Anthropic's Claude API to read book titles and are not stored after the request completes — only the resulting text (titles/authors/genres) is saved to your library.

How we use it

To let you sign in and keep your library private to your account.
To detect books from photos and generate personalized recommendations and summaries, via the Anthropic Claude API.

Where it's stored

Account and library data is stored in Supabase (a hosted Postgres database) with row-level security enabled, meaning only you can access your own data — not other users of the app.

Third parties

Book photos and text you submit for AI features are sent to Anthropic's Claude API to generate results, subject to Anthropic's own privacy policy. Sign-in is handled by Supabase Auth and, if you choose it, Google OAuth.

What we don't do

We don't sell your data.
We don't show ads.
We don't share your library with other users.

Your data, your control

You can delete any book from your library at any time within the app. To delete your account entirely, use the "Delete account" option on the Profile tab — this immediately and permanently removes your account and everything in your library.

Contact

Questions about this policy: arinvangilder@gmail.com