Privacy

Libstack is a reading tracker you can show to friends. This page describes everything it stores about you, who else can see it, and how to remove it.

Signing in

You sign in with Apple or Google. Libstack never sees or stores a password. From your provider it receives an email address and an account identifier, which are what identify you on return visits. If you use Apple’s Hide My Email, Libstack only ever holds the relay address.

What Libstack stores

• Your profile — a display name, a handle, an emoji, and a photo if you add one.
• Your library — the books you add, with title, author and cover from the search provider; which shelf each sits on and the names you give those shelves; whether you are reading or have finished; and your reading progress.
• Your reading days — one record per day you mark as read, which is what a reading streak is counted from. The date is your device’s local date; no location is involved.
• Your notes — free text you write against a book. Readable by you alone.
• Your friendships — who you are connected to, the invite links you create, and the reactions you send or receive on a book.
• A notification token — only if you allow notifications, and only so a friend’s reaction can reach your device.

Who can see it

Your friends, and nobody else. Access is enforced in the database rather than in the app: a request for your profile, books, shelves or notes succeeds only if it comes from you or from someone you are mutually connected to. There is no public profile, no follower model, and no way to browse strangers.

Your library is not on the web. Nothing in your account is served on this website or visible to a search engine. The only page here that reads the database is an invite link, which shows the inviter’s display name and emoji so the recipient knows who sent it.

Two things are yours alone, and not shared with friends: the notes you write on a book, and your reading days. These are enforced by the same database rule as everything above — a request for them from anyone other than you returns nothing, whether or not you are friends.

Reading streaks

A streak is counted from your reading days, which only you can read. A friend cannot see your streak.

Analytics and crash reporting

Libstack uses Firebase Analytics and Crashlytics, both from Google, to count a small number of in-app actions (such as sharing a library card) and to receive crash and performance reports. These carry device and app information and an app-generated identifier. They do not carry your books, your notes or your friends.

On iOS you are asked for permission to track before any of this is associated with an advertising identifier. Libstack shows no advertising, sells no data, and has no advertising or marketing partners.

Services Libstack relies on

• Supabase — the database, sign-in, file storage for profile photos, and the server functions behind invites and account deletion.
• Google — sign-in, notification delivery, analytics and crash reporting, and the Google Books catalogue.
• Apple — sign-in, notification delivery, and the Apple Books catalogue when you look for a place to read a book.
• Kakao — the book catalogue used for Korean titles.
• Vercel — hosting for this website.

When you search for a book, the words you type are sent to a catalogue provider to answer the search. When you open a shop or reader app from a book, you leave Libstack and that company’s own terms apply.

Deleting your account

Settings → Delete account, in the app. It is immediate and it is not reversible: your sign-in, profile, books, shelves, notes, reading days, friendships and profile photo are removed, and there is no restore. See Support for what happens to a friend’s copy of a shared invite.

Data is kept for as long as your account exists, because it is your account — a reading history with a gap in it is not useful to anyone.

Children

Libstack is not directed at children and does not knowingly collect data from anyone under 14.

Changes

If this page changes in a way that affects what is collected or who can see it, the date at the top changes with it.

Contact

Questions about anything here can go to @andrewchung01, which is the channel the app itself uses today.