A focused EPUB reader built for the web and desktop.
Available as:
- A Chrome extension
- A web app
- A browser-powered desktop app (linux, windows and macos)
- Single- and double-column layouts
- Adjustable font size
- Controls for content width, line spacing, letter spacing, and image size
- Code highlighting powered by highlight.js
- Image zooming and copying powered by medium-zoom
- Math rendering and copying powered by MathJax
- Highlights and annotations
- Table of contents and reading progress
- Full-text search
Table of contents:
Search:
Auto-hiding Dock toolbar:
Supports Chrome and Edge 152+, Firefox 154+, and Safari and iOS Safari 26+.
The app uses modern Web APIs directly, with no polyfills or fallbacks for older releases.
See the Browserslist in package.json for the canonical build targets.
Clipboard and local-file features require a secure context and user permission. Translation runs entirely on the device and requires a browser with the built-in Translator API.
Less frequently used options are available through epub.settings in the developer console and are stored in the browser's localStorage:
epub.settings.fonts
epub.settings.textAlignment
epub.settings.translationTargetLanguage
await epub.settings.setSerifFont("Noto Serif, serif")
await epub.settings.setSansFont("Noto Sans, system-ui, sans-serif")
await epub.settings.setMonoFont("Fira Code, ui-monospace, monospace")
await epub.settings.setTextAlignment("justify") // "auto" | "start" | "justify"
await epub.settings.setTranslationTargetLanguage("ja") // BCP 47 language tag
await epub.settings.reset()Font names refer only to locally available browser fonts; the app does not download or install fonts.
The auto text-alignment setting chooses an alignment based on the document language.
The translation target defaults to the browser's preferred language. If support for a language pair is not installed, its model is downloaded only after confirmation in the translation popover.
reset() removes all advanced overrides and restores the defaults.
On each launch, the app logs the current settings and command hints to the console.
Translation languages use BCP 47 tags, including zh-Hans for Simplified Chinese and zh-Hant for Traditional Chinese.
See the official Edge language list or use the Edge Built-in AI Playground to check model availability.
The reader uses the EPUB lang value when available and invokes the Language Detector only when it is missing.
Key platform differences:
| Application | Opening local EPUBs | Saving |
|---|---|---|
| Extension | Select or drop a file on the welcome screen, or open a file://*.epub tab and be redirected to the reader |
Saves the complete EPUB through a file picker and reuses approved file handles |
| Web | Select or drop a file; OS file associations are unavailable | Files opened through the picker can be saved directly; dropped files are saved as downloaded copies |
| Desktop | Launch without arguments to show the welcome screen, or open a file through an OS file association | Associated files are written back by the local service; files selected on the welcome screen use browser-based saving |
Dropping support for old browsers does not mean dropping support for old books.
The parser and typography layers retain common EPUB 2 and EPUB 3 repairs, including legacy namespaces and xlink:href, -epub-* CSS normalization, irregular metadata, and migration of existing annotation data.
These paths preserve publication compatibility, not obsolete browser runtimes.
| Input | Paginated | Scrolled |
|---|---|---|
| Click the left or right side of the screen | Previous or next column | Previous or next screen |
| Mouse Back or Forward button | Previous or next screen in reading order | Previous or next screen in reading order |
Left / Right, h / l |
Previous or next column | Previous or next screen |
Up / Down, k / j |
Previous or next screen | Scroll up or down |
Space |
Not applicable | Scroll down |
| Open the table of contents | t |
t |
| Open search | / |
/ |
| Go to a reading position | Enter a percentage followed by G, such as 50G |
Same |
| Return to the previous position | Ctrl+O |
Ctrl+O |
| Save | Ctrl+S / Command+S |
Same |
- foliate-js for the original renderer and EPUB parser
- Fonts: EB Garamond, Monaspace Argon, Noto Sans, and Noto Serif