Privacy Policy

Last updated: September 2026

TeaderBook is an e-reader for language learners, published by MaxeSoft (“we”, “us”). It opens book files you already own and translates a word or a sentence when you tap it. This policy explains exactly what leaves your device, what we keep, and for how long.

The short version. Your books, your reading position, your vocabulary and your statistics never leave your phone. We run no analytics, no advertising and no trackers. If you use Smart translation, the single word or sentence you tapped is sent through our server to Google Gemini and is not stored and not logged — neither the text you sent nor the translation that came back. Signing in is optional, and the whole app works without it.

1. What stays on your device

The following is stored only in the app's own storage on your phone. It is not uploaded anywhere, and there is no cloud backup or cross-device sync in TeaderBook:

the book files you import, their covers, titles and authors;
your reading position, bookmarks and reading settings (font, theme, margins);
your vocabulary, lookup history, word familiarity marks and review progress;
reading statistics such as time spent reading and words looked up;
translations the app has cached so it does not have to ask twice;
if you sign in, your session and refresh tokens, held in the operating system's secure storage (Keychain on iOS, Keystore-backed storage on Android).

Uninstalling the app removes all of it.

2. Translation methods and what each one sends

You choose the methods in Settings, and the choice decides whether anything is sent at all.

Translation method	Where it runs	What leaves the device
Offline words (Google ML Kit)	On your device	Nothing. The language model is downloaded once from Google's servers; after that translation is local.
Offline translation (OPUS-MT)	On your device	Nothing. The model file is downloaded once from Hugging Face; after that translation is local.
Smart translation (Google Gemini, an AI model)	Our server, then Google	The word or sentence you tapped, the sentence around it when a word needs context, the language pair, and your app's interface language.

With only the offline methods on, the app makes no network request in order to translate. A model download happens only when you agree to it.

How Smart translation handles your text

The request goes to our own server, which forwards it to Google's Gemini API and returns the answer. We do this so the app never has to carry an API key.
We do not store your text and we do not log it. Server logs contain a request identifier, which endpoint was called, how long it took, whether it succeeded and which version of the app sent it — never the word, the sentence or the translation.
Google processes the request as our API provider under its own terms. See Google's Privacy Policy.
We keep a daily total of how many calls were made and how many tokens they cost, so we can reconcile the bill. Those totals carry no device identifier, no language pair and no text.

3. Keeping the service usable: device checks and the free allowance

Smart translation is free within a daily allowance, and the allowance has to be counted and protected from abuse. Two things make that possible:

A device integrity check. Each request carries a token proving it came from a genuine copy of TeaderBook, issued by Google Play Integrity / Firebase App Check on Android and by Apple App Attest on iOS. The token identifies the app, not you.
A per-installation identifier. A random UUID generated by the app on first launch. It is not an advertising ID, it is not derived from any device hardware identifier, and a reinstall produces a new one. It is used for two things: counting your allowance — those rows are deleted automatically after 24 hours, and if you delete them yourself, the app keeps the bare count of what you had spent on your own phone and reports it back, so that deleting is not a way to start the day over — and, if you subscribe, recording that this installation is one of the devices your purchase covers, which lasts as long as the purchase does. Section 5 explains that half.

Our web server applies rate limiting per IP address at the edge. That state is ephemeral; we do not store IP addresses.

4. Signing in (optional)

TeaderBook is fully usable signed out — importing books, reading, the offline methods, the dictionary and review sessions all work with no account and no network. An account exists so a subscription can survive a reinstall.

If you sign in with Google or Apple, we receive from that provider an identity token, verify it, and store:

an account identifier we generate ourselves (not the provider's);
your email address — which, with Sign in with Apple, may be Apple's private relay address if you chose to hide yours;
which provider you used and its stable identifier for you, so the same sign-in finds the same account;
a hash of the refresh token issued to that device, so that signing out can revoke it. The token itself is never stored.

We do not request or store your name, profile picture, contacts or any other profile data. A session lasts one hour and is renewed silently; a refresh token lasts 90 days and is destroyed when you sign out.

5. Subscription and payments

A paid subscription lifts the free allowance. Payment is handled entirely by Google Play or the Apple App Store: we never see or receive your card details, billing address or full purchase receipt. To confirm what you are entitled to, our server stores the plan, its expiry date, which store the purchase came from and an opaque reference the store gave us. Manage or cancel a subscription in your store account.

One purchase covers up to five installations, so that a second phone works without an account. To make that possible we store, next to the purchase, the per-installation identifier of each device that has used it and the dates it was first and last seen — that last date is what decides which installation drops off when a sixth appears. These records last as long as the purchase does rather than 24 hours, and Delete my data removes yours at any time. If you are signed in, your account is stored with the purchase as well, so the subscription can be found again on a device that never restored it.

6. Other features that use the network

Update notice. The app checks whether a newer version exists — through Google Play's in-app update service on Android, and Apple's public app lookup API on iOS. No personal data is sent.
Rate the app. The rating prompt is the store's own dialog; your review goes to the store, not to us.
Pronunciation. Reading a word aloud uses your operating system's built-in text-to-speech. The word is passed to the OS engine, which is governed by Apple's or Google's privacy policy and may process it on-device or in the cloud depending on your system settings.

7. What we never collect

No analytics or telemetry SDKs, no advertising, no third-party trackers.
No book content, book titles, authors or reading positions on our servers.
No vocabulary lists, no review history, no record of what you looked up or when.
No contacts, no photos, no location, no advertising identifier.
We never sell, rent or trade any data. There is nothing here to sell.

8. How long we keep things

Data	Kept for
The text you translate with Smart translation	Not kept at all — held in memory for the duration of the request
Allowance counters (per-installation UUID)	24 hours, then deleted automatically
Installations attached to a subscription (per-installation UUID, first and last seen)	As long as the purchase lasts, or until Delete my data — whichever comes first
Daily cost totals (no identifier, no text)	Kept for accounting
Account and email	Until you delete the account
Refresh token hash	Up to 90 days, or until you sign out
Subscription record	While the subscription is active, and afterwards as required for store and tax records
Server request logs (no content)	A few days, then rotated away

9. Your rights and how to exercise them

Everything below is reachable from inside the app, without writing to us:

Delete my data removes everything tied to your installation — the allowance records and, if you subscribe, this device's place on your purchase. It works whether or not you are signed in, and if you are, it deletes the account too. The purchase itself is left alone, because it is what the store was paid for; the paid plan simply stops applying to this device until Restore registers it again. It does not hand you a second free allowance: the count of what you had already used today stays on your phone. See Delete your account and data.
Delete my account revokes every session immediately and removes the account, its email and its sign-in identities. The rows survive for a 14-day grace window so that an accidental deletion can be undone, and are then permanently purged.
Sign out revokes the tokens held by that device.
Uninstalling removes everything the app stored on the device.

If you are in the EEA or the UK, the GDPR gives you the rights of access, rectification, erasure, restriction, objection and portability. Since we hold so little — an email address, an entitlement, and short-lived counters — most requests are answered by the in-app deletion above. For anything else, write to us at the address in section 12; we answer within 30 days. You may also complain to your local data protection authority.

Our legal bases for the little we do process are: performance of a contract (your account and subscription) and legitimate interests (keeping the free Smart translation allowance from being abused, and knowing what the service costs us).

10. International transfers

Our server runs in a DigitalOcean data centre in Germany, so if you are in the EEA or the UK, what we store stays close to home. DigitalOcean, LLC is a United States company, and the Gemini API that translates your text is operated by Google; both process data under their own safeguards for international transfers, and Google may handle a translation request outside your country. The only personal data involved is an email address, if you chose to sign in — the text you translate is never stored by us, wherever it is processed.

11. Children

TeaderBook is not directed at children under 13, and we do not knowingly collect personal data from them. If you believe a child has provided us an email address through a sign-in, write to us and we will delete the account.

12. Changes and contact

We may update this policy as the app changes. The date at the top says when it was last revised; material changes will be announced in the app or in the store release notes.

Questions, requests or complaints: support@maxesoft.com.