A reader for EPUB, MOBI and comics, built for Supernote e-ink tablets.
Reader is built for e-ink and for low power use. It draws a page once, then does nothing until you ask for the next one. Nothing animates, nothing polls. Sitting on an open page, the app uses no measurable CPU.
- A library with covers, scanned from a folder on the device; each book reopens where you left off, with progress shown as a badge on the cover
- Justified text with real hyphenation, adjustable margins, centered chapter openings, three bundled typefaces
- Two columns in landscape
- Pen highlighting with palm rejection
- Bookmarks, a contents page, and search by title or author
- A chapter scrubber with a tick per chapter, a preview of the destination page as you drag, and a Return control to jump back
- Comics: CBZ and zip-backed CBR, one page per screen, per-book reading direction for manga, in the same library as your books
- A full refresh on every page turn, or a faster mode with periodic clean-up flashes
Reader opens EPUB, MOBI, CBZ, and CBR files that are really zips (many are). Genuine RAR archives do not open. No PDF.
MOBI support covers un-DRMed mobi7 books, which is most sideloaded .mobi files; they read exactly as EPUBs do. Two kinds are refused with a message on the shelf: anything with DRM, and AZW3/KF8, which is what Amazon ships today.
1. Download the APK. Take the latest sn-reader-*.apk from the
Releases page.
2. Install it over USB.
adb install -r sn-reader-2026.07.6.apk
Turn on Debug mode first, in the Supernote's own Settings under security and privacy (the exact wording moves between firmware versions), and check adb devices lists your tablet. Updating later keeps everything: your library, positions, bookmarks, and highlights live in the app's own storage, not the APK.
3. Let it read your files. Reader asks on first launch. If you miss the prompt:
Settings > Apps > Special access > All files access > Reader
This is required. Your books sit in shared storage and Android will not hand them over without it.
4. Add books. Drop .epub, .mobi, .cbz or .cbr files into the Document folder, where Supernote keeps its own. Reader finds them next time you open it, and you can point it at another folder in its settings. Scanning is incremental, so a big library does not mean a slow start.
Tap a book to open it where you stopped. Search filters by title or author as you type, across the whole library regardless of folder. A row of controls covers the rest: covers or a list, all books or just the new / part-read / finished ones, folders or flat, and the sort order.
There is no swiping. The screen is three tap zones:
| Where you tap | What happens |
|---|---|
| The left edge, roughly a quarter of the width | Back a page |
| The right side, roughly the last 40% | Forward a page |
| The strip between them | Show or hide the chrome |
Rotate the tablet and the page becomes two columns. A tap turns both pages at once, and the foot reads pages 3–4 of 12. A spread never crosses a chapter boundary, so a chapter with an odd number of pages ends with a blank right-hand column.
Rotating keeps your place: the page numbering changes because the text reflows, but the words you were reading stay on screen. Lock rotation, under Aa › Screen, pins the reader to its current orientation. The library and settings screens stay upright either way.
The toolbar is two rows: a ‹ back to the library, the book's title, a bookmark ribbon, Contents, and Aa on the first; the current chapter on the second. While the toolbar is up, the page dims by one grey level.
The ribbon is outlined when the current page is unbookmarked, filled when it is. Tap it to bookmark the page in place.
Contents holds three lists behind a Chapters · Marks · Notes header: the chapter list, your bookmarks, and your highlights. It opens on whichever list you last used, per book. Aa holds the display settings. Both close with the ‹ at the top-left; its tap target extends to the edge of the glass.
Highlights are made with the pen; palm rejection keeps a resting hand from leaving marks. Drag the pen across a passage and the highlight follows the nib. Tap an existing highlight for a delete button. The Highlights panel lists them all, each with its chapter and position in the book.
Chapters lists each chapter with its percentage, the current one bold and marked in the margin; tap to go there. Marks and Notes list your bookmarks and highlights, grouped by chapter. A bookmark shows the opening words of the page it saved.
The timeline along the bottom of the toolbar has a tick for every chapter. Drag it and a floating window shows the destination page, from thumbnails prepared once in the background, while a readout names the chapter and percentage. The page itself is drawn once, when you let go. The thumb snaps to chapter starts, bookmarks appear on the track as glyphs, and after any jump Return appears beside the readout to take you back to where you were.
Aa opens a sheet across the bottom of the screen, with three tabs: Text (typeface, size, spacing), Page (margins, justification, hyphenation, publisher styling), and Screen (page turns, the progress bar, rotation, previews). The book stays visible above the sheet, and Text controls reflow it live as you change them.
Publisher styling decides whether a book keeps its own formatting or is normalized to Reader's defaults. Changing any setting reflows the text and keeps your place.
By default every page turn does a full e-ink refresh, which leaves the next page clean of ghosting. Faster page turns switches to a light, fast refresh with a full clean-up flash every 3, 6, or 10 pages as you prefer.
Reader opens CBZ archives, and CBR files that are really zips (many are). Pages show one at a time, fit to the screen, turned with the same taps as a book. Reading direction follows the archive's ComicInfo.xml, and you can flip it per book for manga.
Comics sit in the same library, with the first page as the cover and the same progress badge; your place is kept per comic, and bookmarks work by page. The toolbar is the same, with two differences: a comic has no chapters, so the timeline has no ticks, and scrub previews are decoded as you drag instead of prepared ahead of time.
File type is detected by content, not extension, so a zip named .cbr opens without complaint. A genuine RAR archive does not open; Reader shows a message rather than failing silently.
Two limits: comics are portrait only (no two-page spread in landscape), and pages are fit to the screen with no zoom.
Settings holds app-level options: which folder your books live in, and the version you are running. All display options live in Aa inside the reader.
- Tested on a Supernote Nomad. It should work on a Manta, but that has not been confirmed.
- Sideloaded, not from any app store.
- Everything stays on your device. No accounts, no sync, and the app never touches the network.
- What changed between releases is in
CHANGELOG.md.
Apache 2.0. Use it, change it, redistribute it, including commercially. If you plan to package or redistribute, read NOTICE first for the third-party details.
Kotlin, Gradle, and plain Android Views (no Compose, no WebView). Four modules: :engine is pure Kotlin pagination logic with no Android dependency, testable on an ordinary JVM; :formats parses EPUB and MOBI and measures text; :data is the Room-backed book index; :app is the interface.
You need JDK 21 and the Android SDK, including one package that is easy to miss:
sdkmanager "platform-tools" "platforms;android-36" "platforms;android-37.1" "build-tools;36.0.0"
platforms;android-37.1 is not a typo. A dependency forces compileSdk = 37, and without that package the build fails with an error naming an AAR file rather than the missing platform.
Point Gradle at your SDK with a local.properties in the repo root:
sdk.dir=/path/to/android-sdk
Then:
./gradlew test
./gradlew :app:assembleDebug
adb install -r app/build/outputs/apk/debug/app-debug.apk
Two things to leave alone: the Android Gradle Plugin brings its own Kotlin compiler, so do not apply the Kotlin Android plugin separately, and do not move Kotlin past 2.2.10. A mismatch there crashes compiler-plugin startup rather than failing with anything you can read.