PRIVACY POLICY

Lumen — EPUB & PDF Reader

Effective date: May 16, 2026

Developer: Kryptow

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1. OVERVIEW

Lumen is an e-book and PDF reader. We respect your privacy: our app 

does not collect personal data from you, does not require account 

creation, and does not send your data to our servers. All your reading 

data is stored only on your device.

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2. INFORMATION WE COLLECT

Lumen does not collect personal identifiers (name, email, phone, etc.).

You do not create an account inside the app.

The following data is stored ONLY ON YOUR DEVICE and never sent 

anywhere:

  • Books you add to your library (file paths)

  • Reading progress (page, chapter)

  • Highlights and notes

  • Reading preferences (font, theme, margin, etc.)

  • Bookmarks

This data is deleted when you uninstall the app.

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3. THIRD-PARTY SERVICES

Lumen uses the following external services for dictionary and 

translation features:

a) Free Dictionary API (api.dictionaryapi.dev)

   When you select a word and use the "Definition" feature, ONLY the 

   selected word is sent to this service. No personal data, book 

   information, or location is sent.

b) Google Translate (translate.googleapis.com)

   When you use the "Translate" feature, ONLY the selected text 

   fragment is sent to Google. Google's own privacy policy applies:

   https://policies.google.com/privacy

c) Android Text-to-Speech (TTS)

   The read-aloud feature uses your device's local TTS engine. Text 

   does not leave your device (subject to the policy of the TTS engine 

   installed on your device).

Lumen does not use any analytics (Google Analytics, Firebase, etc.) 

or advertising SDKs.

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4. PERMISSIONS

Lumen uses the following Android permissions:

  • File reading permission: To open EPUB/PDF files you select.

  • Internet access: For dictionary and translation features (only 

    when you request them).

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5. CHILDREN'S PRIVACY

Lumen is not directed at children under 13. We do not knowingly 

collect information from children under 13.

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6. DATA SECURITY

All your data is protected by your device's security systems. Because 

Lumen does not send your data over the internet, there is no risk of 

server breaches affecting your data.

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7. POLICY CHANGES

This policy may be updated from time to time. Significant changes will 

be announced with app updates. The current version is always published 

on this page.

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8. CONTACT

For questions:

Email:freebookreader@mail.ru

Developer: Kryptow