# EPUB Ninja - eBook Reader
> A fast, lightweight EPUB and CBZ reader in your browser sidebar. Import books and comics, pick up where you left off, and read without distractions. 100% local your files never leave your browser.
Canonical page: [https://chrome-stats.com/d/epub-ninja-ebook-reader](https://chrome-stats.com/d/epub-ninja-ebook-reader)
## Overview
- **ID:** `epub-ninja-ebook-reader`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** Digital Fracture
- **Category:** appearance,bookmarks,photos-music-videos
- **Daily users:** 62
- **Weekly downloads:** 5
- **Version:** 1.0.2
- **Last updated:** 2026-04-09
- **First published:** 2026-04-05
- **Size:** 1.38 MB
- **Data as of:** 2026-09-10
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/epub-ninja-ebook-reader/)
- **Website:** [https://www.digitalfracture.co.uk](https://www.digitalfracture.co.uk/)
- **Privacy policy:** [https://addons.mozilla.org/firefox/addon/epub-ninja-ebook-reader/privacy/](https://addons.mozilla.org/firefox/addon/epub-ninja-ebook-reader/privacy/)
## Description
EPUB Ninja is a clean, distraction-free eBook and comic reader that lives in your Firefox sidebar. Import your EPUB and CBZ files, and start reading no cloud, no tracking.
Just £4.50 a year for the full Ninja suite - RSS Ninja, EPUB Ninja and Snooze Ninja - with every feature included and no extra charges.
FEATURES
• Sidebar eBook Reader: Read EPUBs right inside Firefox. No separate app needed.
• CBZ Comic Support: Import comic book archives with single page, two-page spread, and fullscreen viewing modes.
• Book Library: Manage your collection with cover art, reading progress, and sort by recent, title, or progress.
• Dark & Light Themes: Full dark mode that themes the entire browser chrome to match.
• Table of Contents: Slide-out chapter navigation. Jump to any section instantly.
• Bookmarks: Bookmark any chapter and return to it with one click.
• Full-Text Search: Search across every chapter of your book.
• Reader Settings: Font size, font family, line height, margins, text alignment, and paragraph spacing.
• Keyboard Navigation: Arrow keys to navigate, F for fullscreen, 1/2 for page modes, Escape to close panels.
• Reading Progress: Automatically saved. Close the browser and pick up exactly where you left off.
• 100% Local: All data stored in your browser. Books never leave your device. No servers, no uploads, no tracking.
SUPPORTED FORMATS
• EPUB 2 and EPUB 3 (eBooks)
• CBZ (Comic Book ZIP archives)
HOW IT WORKS
- Click the EPUB Ninja icon in your toolbar to open the sidebar.
- Click "Import EPUB / CBZ" and select your files.
- Click a book to start reading.
Your books are stored locally in IndexedDB and browser storage. Nothing is sent anywhere.
Part of the Ninja suite from the makers of RSS Ninja.
Website: https://rssninja.co.uk
## Rankings
- #14,589 — Overall
- #27 — book
- #92 — comic
- #94 — reader
- #129 — booking
- #197 — header
## Permissions and access
### Permissions
- `storage`
- `unlimitedStorage`
- `tabs`
- `theme`
### Host permissions
- `https://rssninja.co.uk/*`
## Safety
- **Risk impact:** Moderate risk impact
- **Risk likelihood:** Moderate risk likelihood
### Analysis details
- Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
- This extension has low user count. Unpopular extensions may not be stable or safe.
> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).
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Source: [Chrome-Stats](https://chrome-stats.com/d/epub-ninja-ebook-reader)