Privacy Policy

EPUB Reader Online browser extension and web reader · Last updated: 4 September 2026

Short version

Your books never leave your device. EPUB Reader Online opens and renders .epub files entirely inside your browser. We do not collect, upload or have access to the content of any book you open, on the extension or on the web reader at readepub.com.

What the extension does with your files

The extension opens .epub files you already have — a file you downloaded, a file you drag into the reader, or (only if you turn the optional toggle on) a file you followed a link to on a website. The book is parsed and rendered locally, in the reader tab, using the open-source epub.js library running in your browser. The file itself is never uploaded anywhere.

What is stored, and where

• Reading position (chapter/location) and your last 10 opened books — stored locally in chrome.storage, on your device only, so the extension can resume where you left off
• Display settings (font, theme, page width, layout mode) and the anonymous installation identifier below — stored in chrome.storage.sync, which means Chrome copies them between the browsers you are signed into with the same Google account, so the reader looks the same on your other computer. That copying is done by Google as part of your own Chrome profile sync; we do not receive these values, and they are covered by Google's privacy terms, not ours. Book titles, files and reading positions are not put in sync storage
• A randomly generated, anonymous installation identifier — used only to attribute the anonymous usage events below to one installation, not to a person

None of the above is sent to us. It is removed if you uninstall the extension or clear its storage.

Permissions and why they are needed

• downloads — detect when a .epub file finishes downloading, so the reader can open it automatically
• storage — reading positions, display settings and the anonymous installation id described above
• declarativeNetRequest — redirect a double-clicked local .epub file (and, only if you enable the optional toggle, an .epub link on a website) to the reader page, instead of letting the browser download it again
• host access to file:///* — read the book file you are opening; requires the separate "Allow access to file URLs" toggle you control in chrome://extensions
• optional host access (off by default) — only requested if you turn on "Open EPUB links from websites" in the extension's settings; used solely to redirect .epub links to the reader

The extension does not request access to your browsing history, bookmarks, cookies, tabs content unrelated to opening a book, or any account.

Anonymous usage statistics

To understand whether the reader works for people, the extension reports a small number of anonymous product events: installation, that the welcome page was seen, that a book was opened and by which method, that search or a display setting was used, and interactions with the rating widget. These events carry the random installation id described above, an environment flag and, where relevant, a display-mode name or a star rating — never a file name, book title, book content, URL or anything else that could identify you or what you are reading.

Events go directly from your browser to Amplitude, Inc., our analytics provider, whose infrastructure is in the United States. If that request cannot be delivered, the same event is sent instead through a relay server we run at readepub.com/e, which accepts only the fixed set of event names above and forwards them on to Amplitude; it never receives book content. Either way, the request carries your IP address, as any request on the internet does. Amplitude uses it to derive an approximate country and then discards it; our relay does not write it to its analytics log.

Web pages on this site (readepub.com) additionally use Yandex Metrica and Google Analytics to understand traffic to the site itself, separately from the extension.

How we process data

We process the anonymous usage events described above for one purpose only: to see whether the reader actually works — whether books open, whether search is used, whether people come back. The legal basis is our legitimate interest in keeping a free product working; there is no profiling, no advertising audience and no attempt to identify you behind the random installation id.

Events are held by Amplitude, Inc. (United States) under their own terms as our processor, and our relay server keeps only what is needed to forward them. If you would rather send nothing at all, uninstalling the extension stops it immediately, and the anonymous id is deleted with the extension's storage.

One thing does travel as free text: the uninstall page asks a single optional question, "Why have you deleted EPUB Reader Online?". If you type an answer and send it, that answer is submitted to a Google Form we own and is stored by Google on our behalf, together with the anonymous installation id. Whatever you write there is up to you — please do not include anything personal, because we read those answers as plain text. Leaving the page without sending stores nothing.

What we never do

• We do not upload, read or have access to the content of any book you open
• We do not sell or transfer data to third parties for advertising
• We do not record your screen or browsing session outside the reader tab
• We do not require an account, and there is no server-side library or sync in this version
• There are no ads in the extension

Contact

Questions about this policy: see the developer contact on the EPUB Reader Online Chrome Web Store listing.