Draft — company details will be added after registration with the Dutch Chamber of Commerce.

Privacy policy

Version 12 November 2026 (draft)

Who is responsible?

[Company name], [address], Chamber of Commerce no. [number], the Netherlands, is responsible for processing personal data in the Sayfo app. Contact: [email protected].

What data?

• Your email address, or the identifier of your Apple or Google account if you sign in with it.
• Your birth year and month (no day).
• Your language preference.
• The contents of your bookcase: the books you add, their status, copies and condition, reading dates, lists, loans and your own notes.
• Your public profile: username and — if you fill them in — display name and bio.

We do not process your full name, full date of birth, address, location, contacts, advertising IDs or camera images.

What for?

Only to make the app work: managing your account and storing and syncing your bookcase between your devices. We use no ads, tracking or profiling and we do not sell data.

Age

Sayfo is for ages 13 and up. We only ask for your birth year and month to decide which features you can use: following, being found and sharing books are available from 16. Until then, everything in your bookcase is visible only to you. Your birth month is never visible to others.

Your public profile

You automatically get a random username, which you can change (up to 2 times per 30 days). A name you give up is held for you for 30 days. Your username, display name and bio are visible to other signed-in users aged 16 and over. Your books are visible only to you by default; you choose per book whether friends or everyone may see them. Notes and the condition of your copies are never visible to others.

Moderation

You can report profiles and shared books and block other users. The people you report or block are not told. When you report something, we keep what was reported and why; resolved reports are deleted after 12 months. Profile texts are checked automatically for links, phone numbers and inappropriate words. If we take action against your account or profile, you see the reason in the app and can appeal.

Sayfo Plus

If you buy Plus, Apple or Google handle the payment; we never see payment details. Our service provider RevenueCat processes the purchase under a random account ID, without your name or email address. With Plus you can keep photos of your own copies; they are visible only to you and stored without location data. With Recognise from photo, the photo is read on your device only and never sent.

Camera

The camera is only used to read barcodes. Images are not stored or sent.

Book data

To fetch information about a book, our server sends the ISBN or your search term to public book sources: Open Library, Google Books, national libraries (Netherlands, Germany, France), Wikidata and possibly ISBNdb. No data about you is sent along.

Errors and updates

If the app crashes, we send a technical error report to our service provider Sentry (in the EU): what went wrong, on what type of device and which app version. Without your name, email, books or notes. You can turn this off in Settings → About. On start-up, the app checks via Expo whether an improvement is available.

Who receives your data?

• Supabase — hosting your account and bookcase (EU, Frankfurt).
• Apple and Google — only if you sign in with their account or buy Plus.
• RevenueCat — processing Plus purchases (pseudonymous account ID).
• Sentry — error reports without personal data (EU).
• Expo — delivering app updates (technical request with app version and platform).

We have data processing agreements with these providers.

How long?

As long as your account exists. When you delete your account, all your data is deleted immediately and permanently. We keep technical logs as briefly as possible; recent username changes for 30 days, moderation logs for 24 months.

Your rights

You can view and export your data in the app (Settings → Export my data), correct it, and delete it (Settings → Delete account, or via this page). For other requests, such as objection or restriction: [email protected]. You can file a complaint with the Dutch Data Protection Authority (Autoriteit Persoonsgegevens) or the authority in your country.

Security

Connections are encrypted and your data is technically shielded, so only you can see your bookcase and only what you choose is shared.