Margin

A small desktop markdown editor where the document is rendered as you type, with a folder tree on the left, tabs for open files and a print button. Nothing else.

Built with Tauri 2 (Rust) and Svelte, using Milkdown for WYSIWYG editing.

Features

• WYSIWYG editing: headings, lists, task lists, tables, code blocks with syntax highlighting, math (KaTeX), links and images render in place.
• Source mode (Ctrl+/, ⌘/ on macOS) for editing the raw markdown.
• Any text file: CSS, C++, PHP, Python, JSON and 100+ other languages open in a code editor with syntax highlighting, line numbers, folding and search (Ctrl+F). They're saved exactly as written.
• Binary files (images, PDFs, archives…) and files over 20 MB open in your system's default app.
• Folder tree of a folder's files and sub-folders. Double-click a file (or select it and press Enter) to open it. Hidden files and node_modules are left out. It updates when files change on disk.
• File search above the tree (Ctrl+Shift+F): finds files by name anywhere in the project, including folders you haven't expanded. Words can be in any order (read md finds README.md), and they can match folder names too (docs plan). Results replace the tree while you type, with the best matches first. Use ↑/↓ and Enter to open one, and Esc to clear. Hidden files and the folders hidden in Preferences are skipped.
• Tabs: a dot marks unsaved changes. You're asked before unsaved work is closed. Right-click a tab for more options.
• Print button (Ctrl+P). To make a PDF, pick "Save as PDF" in your system's print dialog. Code prints with syntax highlighting.
• Images: relative paths like assets/pic.png display correctly. Pasted images are saved into an assets/ folder next to the document.
• Links: Ctrl/⌘+click a link to open it. Links to other .md files open in a new tab.
• Terminals: open as many as you like from the Terminals section at the bottom of the sidebar (or Ctrl+Shift+`). The first one splits the window, with documents on top and the terminal below. Drag the divider to resize it. Only the current terminal is shown; click one in the sidebar to switch. Hiding the terminal area (Ctrl+`) keeps the shells running, and typing exit closes a terminal. The shell is your default one (PowerShell on Windows when installed) and starts in the open folder.
• Projects: opening a folder (sidebar button, main menu, or dropping it on the window) closes the previous folder's documents, asking first about unsaved changes. Each project remembers its open files, the active tab and the expanded tree folders in ~/.margin/projects/, and gets them back the next time you open it, including when the app starts.
• Open Recent (Ctrl+R, also in the main menu) lists recently opened folders and files, kept in ~/.margin/recent.json. When no document is open, the window shows the project's recent files and your recent folders; with no folder open, it suggests opening one.
• Opening files: double-click a .md file once the app is installed (file association), or drop files or a folder on the window.
• Preferences (Ctrl+,, in the main menu): theme (system, light, dark), compact spacing, separate interface and document text sizes, document and code fonts, color vision modes for red–green and blue–yellow color blindness, and options for every behavior: the file tree, projects and history, both editors, terminals (shell, colors including GitHub's colorblind and tritanopia themes, cursor, scrollback) and printing. Changes apply immediately and are saved to ~/.margin/settings.json.

Design

The interface follows the GNOME Human Interface Guidelines and uses libadwaita's colors, type scale and widget styles, implemented in CSS so it looks the same on Windows, macOS and Linux:

• Header bars instead of a system title bar. They hold the window buttons, a centered window title and the main menu. On macOS the native traffic-light buttons sit in the header bar.
• Split view with a sidebar for the folder tree, a tab bar like AdwTabBar, and empty-state pages like AdwStatusPage.
• In-app dialogs and toasts like AdwAlertDialog and AdwToast, instead of system message boxes. File pickers stay native.
• A main menu with access keys, plus Keyboard Shortcuts and About dialogs.
• Light and dark styles, following the system, and a high-contrast variant.

Colors and metrics live as CSS variables in src/app.css, named like libadwaita's own (--accent-bg-color, --headerbar-bg-color, …). The UI font is Inter, which GNOME's Adwaita Sans is based on. It's bundled, so it's the same on every OS.

Keyboard shortcuts

On macOS, use ⌘ instead of Ctrl. All shortcuts are also listed in the app under Main Menu → Keyboard Shortcuts (Ctrl+?).

Action	Shortcut
New document / new tab	Ctrl+N / Ctrl+T
Open file / folder	Ctrl+O / Ctrl+Shift+O
Open recent	Ctrl+R
Find a file in the project	Ctrl+Shift+F
Save / Save as	Ctrl+S / Ctrl+Shift+S
Close tab	Ctrl+W (or middle-click)
Next / previous tab	Ctrl+Page Down / Ctrl+Page Up, Ctrl+Tab
Go to tab 1–9	Alt+1 … Alt+9
Markdown source mode	Ctrl+/ (in code files: toggle comment)
Show / hide sidebar	F9
New terminal	Ctrl+Shift+`
Show / hide terminals	Ctrl+`
Copy / paste in a terminal	Ctrl+Shift+C / Ctrl+Shift+V (⌘C / ⌘V on macOS)
Preferences	Ctrl+,
Main menu	F10
Print	Ctrl+P

Development

Install the Tauri prerequisites for your OS first: Rust, Node.js 20+, and on Linux the WebKitGTK development packages. Then:

npm install
npm run tauri dev

Building installers

Tauri builds installers for the OS it runs on. Run this on each platform:

npm run tauri build

Output goes to src-tauri/target/release/bundle/:

OS	Installers	Build on
Windows	msi/*.msi, nsis/*-setup.exe	Windows 10/11
Linux	appimage/*.AppImage, deb/*.deb, rpm/*.rpm	Ubuntu 22.04 or older (see below)
macOS	dmg/*.dmg, macos/*.app	macOS (Intel or Apple Silicon)

To build only some formats, list them, for example: npm run tauri build -- --bundles appimage,deb.

Notes per platform

• Linux: an AppImage only runs on systems with the same or a newer glibc than the system it was built on, so build on the oldest distro you want to support. The AppImage is large (~80 MB) because it includes WebKitGTK. The .deb and .rpm are ~4 MB because they use the system's copy.
• macOS: for a single .dmg that runs on both Intel and Apple Silicon:

  rustup target add aarch64-apple-darwin x86_64-apple-darwin
  npm run tauri build -- --target universal-apple-darwin

  Without signing and notarization (Apple Developer account, $99/yr), people opening the app see an "unidentified developer" warning. They need to right-click the app and choose Open the first time.
• Windows: unsigned installers show a SmartScreen warning ("More info → Run anyway"). Signing the installer with a code-signing certificate removes it.
• Windows from Linux (experimental): Tauri can cross-compile the NSIS .exe installer (not the .msi):

  cargo install --locked cargo-xwin
  rustup target add x86_64-pc-windows-msvc
  sudo apt install nsis lld llvm
  npm run tauri build -- --runner cargo-xwin --target x86_64-pc-windows-msvc

Signing the Windows installer

Unsigned installers work, but Windows shows a SmartScreen warning. The project is set up for Azure Artifact Signing (formerly "Trusted Signing"), which individual developers in the USA and Canada can use for about US$10/month.

One-time setup in Azure

1. Create a pay-as-you-go Azure subscription. Free and sponsored subscriptions don't work.
2. Create an Artifact Signing account. Note its name and region.
3. Complete identity validation as an individual (government ID and a selfie). This can take a few days.
4. Create a certificate profile of type Public Trust. Note its name.
5. Create an App Registration in Microsoft Entra ID. Give it a client secret, and on the signing account give it the role Artifact Signing Certificate Profile Signer.

On the Windows build machine

1. Install the Windows 11 SDK (for signtool), .NET 8 and the Azure CLI.
2. Install the signing tool: cargo install artifact-signing-cli
3. Set the App Registration's credentials as environment variables: AZURE_CLIENT_ID, AZURE_CLIENT_SECRET, AZURE_TENANT_ID. Don't commit these.
4. In src-tauri/tauri.signing.conf.json, replace REGION, ACCOUNT_NAME and CERTIFICATE_PROFILE with your values. For the region, use the account's endpoint, for example https://eus.codesigning.azure.net for East US.
5. Build with signing:

   npm run tauri build -- --config src-tauri/tauri.signing.conf.json

   The app, the .msi and the setup .exe are all signed. To check, open the installer's Properties → Digital Signatures.

Normal npm run tauri build stays unsigned, so builds keep working without the Azure setup.

Project layout

src/                     Svelte frontend
  routes/+page.svelte    window layout, tabs, shortcuts, session
  lib/Editor.svelte      one editor per tab (Milkdown + CodeMirror source mode)
  lib/codemirror.ts      code editor setup, languages, printable highlighting
  lib/TreeNode.svelte    folder tree
  lib/FileSearch.svelte, lib/SearchResults.svelte  file search above the tree
  lib/recent.svelte.ts   recently opened folders and files
  lib/settings.svelte.ts preferences: defaults, saving, applying the appearance
  lib/PreferencesDialog.svelte  the Preferences dialog
  lib/terminalThemes.ts  terminal colors (GNOME and GitHub)
  lib/RecentDialog.svelte, lib/RecentList.svelte  Open Recent and the empty window's lists
  lib/TerminalView.svelte  one terminal (xterm.js)
  lib/terminals.svelte.ts  open terminals and the terminal area's state
  lib/ui/                GNOME-style widgets: menus, dialogs, toasts, window buttons, icons
  lib/state.svelte.ts    tabs and tree state
  lib/api.ts             calls into Rust, path helpers
  app.css                libadwaita colors and widget styles, document and print styles
src-tauri/
  src/lib.rs             file access, file search, folder watching, image saving, printing
  src/terminal.rs        shells in pseudo-terminals (ConPTY on Windows)
  tauri.conf.json        window, bundling and file associations
  tauri.macos.conf.json  macOS window: native buttons over the header bar

Known limitations

• On save, the editor writes the document in its own consistent markdown style (for example - for bullets and *emphasis*). The content is unchanged, but the diff of a hand-formatted file can be noisy the first time you save it.
• Images pasted into a new document go into assets/ only after the document has been saved once.

License

MIT. See CONTRIBUTORS.md for the people who built Margin.