App "Knihovnička" (web, iOS, Android) · last updated 13 September 2026
The controller is rewrite s.r.o., Konventná 6, 811 03 Bratislava, Slovakia, Company ID
55 316 361 ("we"). Knihovnička is a personal app for managing your home library (audiobooks, e-books,
printed books). This document explains what personal data we process, why, and what rights you have.
What data we process
Account — email address, name and account identifier. When you sign in with Google or Apple,
we receive your email and name from that service (Apple may provide a private relay address). Passwords are
stored only in hashed form.
Library content — the books you add (title, author, ISBN, cover, genre), ratings, reviews,
notes, highlights, bookmarks, tags, reading status and listening or reading position, so they sync across
your devices.
Cover photos — images you upload as a book cover.
Social features — your friends list and friend requests, family membership, messages,
recommendations and reviews that your friends can see.
Moderation — content reports (the reported content, reason and note), your list of blocked
users and your acceptance of the community guidelines. Profanity in messages and reviews is hidden
automatically.
Storage connection (NAS) — the NAS address and username; if you share your NAS settings with
your family, also the access password. Only you and the family member you shared it with can see this data. If
you share your NAS through Tailscale, we pass the family member's email to Tailscale to send the invitation.
History and usage statistics — what and when you listened to or read (History) and aggregated
data on which parts of the app are used, so we can improve it. Detailed usage records are deleted after 35 days;
only aggregated statistics are kept.
Subscription — subscription status and purchase history (see below).
What we do not process
We do not store your audio files or e-books on our servers — they play from your NAS or your
device. Books downloaded for offline listening stay only in the app's storage on that device and are not backed
up or transferred to other devices.
We do not collect location, phone contacts, health data or advertising identifiers.
Photos of pages and shelves taken for scanning (OCR) are processed on the device.
Crash logs and diagnostics are stored only on the device and are sent only if you share them yourself.
Book search queries are sent to catalogues (Google Books, Open Library, a publisher partner feed) only to
return results, without being linked to your identity.
How we use the data and legal basis
To provide the service — account, library sync, social features, subscriptions (performance of a contract).
For security and content moderation — reports, blocking, abuse prevention (legitimate interest).
To improve the app — aggregated usage statistics (legitimate interest).
To meet legal obligations — accounting and tax records.
We do not sell data and do not use it for advertising or for tracking across apps and websites.
Where the data is stored and who processes it
Supabase, Inc. — database, authentication and cover storage.
Vercel Inc. — hosting of the web app.
Google and Apple — sign-in with their account (if you choose it).
Tailscale Inc. — only if you share your NAS with your family through Tailscale.
The payment processors listed below.
Some processors may also process data outside the EU on the basis of standard contractual clauses.
Payments and subscriptions
When you purchase a Plus or Family subscription, we process your email, account identifier and subscription status in order to
provide and bill the service (legal basis: performance of a contract). We keep invoices and tax documents for the
period required by law. We use the following processors to handle payments:
Apple (App Store) and Google (Google Play) — payments and subscriptions in the mobile
apps. Card details are processed directly by these stores; we only receive the subscription status.
Stripe Payments Europe, Ltd. — payments on the web. Card details are processed directly by Stripe.
RevenueCat, Inc. — combines the subscription status from the App Store and Google Play under
your account identifier.
How long we keep data
We keep account and library data for as long as you use your account. When you delete your account, we erase all
related data, except records we are required to keep by law. Detailed usage records are deleted after 35 days.
Your rights
You can view and edit your data directly in the app at any time.
Account deletion — in the app under Settings → Account → Delete account; the account and all
data are permanently erased. Steps, including deletion by email without the app: knihovnicka.app/zmazanie-uctu-en.html.
Portability — you can export your library (JSON/CSV) in Settings.
You have the right of access, rectification, restriction of processing, objection, and the right to lodge a
complaint with the Office for Personal Data Protection of the Slovak Republic.
Children
Social features are not intended for children under 13.
Contact
If you have any questions about privacy, contact us at
info@rewrite.sk.