Linwood Butterfly vs Saber

Linwood Butterfly

• Handwritten lecture notes and PDF markup with a stylus
• People who want a free, AGPL-licensed note app on Android and desktop
• Nextcloud users who want their notes synced over WebDAV

Saber

• Students and others who take notes by hand on a tablet
• Marking up PDFs and printouts in a dark room
• People who want an open-source handwriting app on every device

Linwood Butterfly

• iOS is a preview only: an unsigned IPA that has to be sideloaded with AltStore or Sideloadly, and it is not on the App Store.
• There is no hosted sync service. Remote storage supports only WebDAV, and it is not available in the web version.
• Collaboration is experimental and has to be switched on with an experiment flag.
• The web app performs better in Chromium-based browsers; the docs say Firefox and Safari lack the WebAssembly features it uses.

Saber

• Syncing needs an account on a Nextcloud server: the official Saber one, another provider's, or your own.
• Extra storage is bought by sponsoring the developer on GitHub Sponsors, then emailing him to have the account upgraded by hand.
• The server owner cannot read notes but can see sign-up details, connecting devices and metadata such as the size of each note.
• On Linux the developer recommends the Flatpak, since the AppImage does not work on all systems.

Linwood Butterfly

Infinite canvas with editable elements

Handwriting, shapes and imported media sit on an unbounded canvas, and each element can be moved, resized, recolored and reorganized after it is placed.

Pen and drawing tools

Stroke width, color, smoothing and texture are adjustable, and the toolbox adds labels, shapes, polygons, tables, rulers, grids, stamps, a laser pointer and a presentation tool.

Import and export

Imports PDFs, images, SVG, Markdown, Xournal++ files and OneNote sections. Exports to PDF, SVG, image and Xournal++, plus its own documented .bfly and .tbfly formats.

Templates and packs

Templates bundle backgrounds, tools, layers, areas and pages for new documents, and packs hold reusable stamps, palettes and styles that are available across documents.

Local storage with WebDAV sync

Notes are saved to a folder on the device. The native apps can add a WebDAV connection such as Nextcloud and mark remote files for offline editing.

Experimental collaboration

Behind an experiment flag, several people can edit one document at once through an end-to-end encrypted Swamp relay or a WebSocket server run on one participant's computer.

Saber

Highlighter that keeps its color

The highlighter does not darken where a stroke crosses itself, and it is drawn underneath the ink, so the writing below stays clear.

Dark mode that inverts notes

Dark mode darkens the notes as well as the interface, giving light ink on a dark page. Images and PDFs are inverted too, so printouts and textbooks match.

Nested folders

Notes are organized in folders that can be nested without limit, and the most recent notes are listed on the home screen.

Encrypted sync

Notes are encrypted with a randomly generated key before upload, so the server owner cannot read them. The key stays in secure storage on the device.

Choice of Nextcloud server

Sync runs on Nextcloud: the official Saber server hosted in the Netherlands, another Nextcloud provider, or a server you host yourself.

Apps on five platforms

Saber is on Google Play and F-Droid for Android, the App Store for iPhone, iPad and Mac, Flathub or an AppImage for Linux, and has a Windows installer.

Linwood Butterfly

• Butterfly$0

  The full app for Android, Windows, macOS and Linux, a web app that installs for offline use, and a Docker image for hosting the web app yourself.

Saber

• Free$0

  The full app, plus 5 GB of storage for every account on the official Saber Nextcloud server.

• StandardAny amount

  per month, as a GitHub Sponsors sponsorship

  10 GB of storage on the Saber server for a monthly sponsorship of any size. Free for students who email proof of status.

• Premium$5

  or more per month, as a GitHub Sponsors sponsorship

  50 GB of storage on the Saber server.

• Hoarder$7

  or more per month, as a GitHub Sponsors sponsorship

  100 GB of storage on the Saber server.

Linwood Butterfly

No public discounts listed.

Saber

• Education

  Standard storage plan free for students

  The pricing page gives students the 10 GB Standard plan free. They email the developer their Nextcloud username and proof of student status, such as a UNiDAYS ID.