Guide

1. Install

1. Download the DMG free of charge from the download section of this website. The Mac edition is distributed only on this website, and the DMG is notarized by Apple.
2. Open the DMG and drag SSEM MarkdownEditor to the Applications folder. Don’t run it from inside the DMG; open the copy in Applications.
3. Open it from the Applications folder or Launchpad. The first time, if macOS asks whether to open an app downloaded from the internet, click Open. Requires macOS 14 Sonoma or later.
4. The preview loads its rendering libraries from the internet (jsDelivr CDN), so make sure you are online when you first use it.

2. Create, open and save

• New document: ⌘N. Or start from File › New from Template: README, Meeting Notes, Technical Documentation, Blog Post, Project Proposal, API Documentation or Changelog.
• Open: ⌘O, or drag a .md file onto the window.
• Recent files: File › Open Recent. Clear Recent Files empties the list.
• Save: ⌘S. Documents are saved where you choose (or in iCloud Drive).

3. Views and themes

• Use the view buttons at the top right of the window or the shortcuts: Editor Only (⌃⌘1), Editor and Preview (⌃⌘2), Preview Only (⌃⌘3).
• In split view, the editor and preview scroll together.
• Pick a preview theme — GitHub Dark, GitHub Light, Notion or Paper — from the Template menu at the bottom right.
• Change the editor’s colors in View › Syntax Theme.

4. Mermaid diagrams

Set a code block’s language to mermaid and the preview draws the diagram.

```mermaid
graph TD
    A[Open document] --> B{Contains Mermaid?}
    B -->|Yes| C[Render diagrams]
    B -->|No| D[Render Markdown only]
```

5. Diagram Studio

• Edit an existing diagram: double-click it in the preview, or choose Diagram › Edit First Diagram in Document….
• New diagram: Diagram › New Diagram in Diagram Studio… (⇧⌘D). When you apply it, it’s inserted as a code block at the editor’s cursor.
• Visual editing (flowcharts): add, rename and delete nodes and choose from 9 shapes (Rectangle, Rounded, Stadium, Subroutine, Database, Circle, Decision, Hexagon, Flag). Give connections one of 6 line styles and a label, and switch the layout direction (Top → Down, Left → Right, Bottom → Up, Right → Left).
• Canvas: click a node to select it. In Connect mode, click two nodes in turn to link them. Zoom in, zoom out and zoom to fit.
• Code mode: edit any Mermaid type — sequence, class, state, ER, Gantt, pie, mindmap and more — and the canvas re-renders as you type. You can also start from a starter template.
• Export: PNG Image (2×), SVG Vector, or Copy as PNG to the clipboard.
• Apply or cancel: Apply (⌘↩) replaces the diagram’s code block in your document. Cancel (esc) closes without changing the document.

6. Math and code

• Math is rendered with KaTeX: inline with $...$ or \(...\), display with $$...$$ or \[...\].
• Add a language name to a code block (e.g. swift, python, json) for syntax highlighting in 15+ languages. Every block gets a copy button.

7. PDF export and printing

• File › Export as PDF… (⇧⌘E)
• File › Page Setup… (⇧⌘P), File › Print… (⌘P)

8. iCloud

File › iCloud › Save to iCloud saves to the app’s iCloud Drive folder, and Open iCloud Folder in Finder shows that folder. If iCloud Drive is off you’ll see “iCloud is not available” — turn on iCloud Drive in System Settings › Apple Account › iCloud.

9. Keyboard shortcuts

10. Updates

Starting with 1.0.1, the app checks for a new version once a day. When one is available, a window shows what’s new; click Install Update and the app downloads it, installs it and relaunches. An update is installed only after both Apple’s notarization and our digital signature (EdDSA) check out.

• Check now: app menu SSEM MarkdownEditor › Check for Updates…
• Turn automatic checks on or off: Automatically Check for Updates in the same menu
• Still on 1.0? Version 1.0 can’t update itself, so this one time download the new DMG from the download section, quit the app (⌘Q) and replace it in your Applications folder. After that, updates arrive automatically.

Either way, your documents and settings stay as they are.

11. Windows edition

We recommend installing the Windows edition (1.0.1) from the Microsoft Store. The package is signed by Microsoft, so there is no “Windows protected your PC” warning, and the Store updates it automatically. On PCs without the Store, get the ZIP from the Windows download on the home page, extract it and run MarkMermaid.exe — there is no installer.

• Shortcuts: use Ctrl where the Mac uses ⌘. New document CtrlN, new window CtrlShiftN, open CtrlO, save CtrlS, save as CtrlShiftS, print CtrlP.
• Views and themes: choose Editor Only / Preview Only / Split View and the Dark / Light theme from the View menu.
• Mac-only features: Diagram Studio, math (KaTeX), document templates, PDF export and iCloud saving. For a PDF, choose “Microsoft Print to PDF” in the print dialog.
• Updates: the Store updates the Store edition automatically. The ZIP edition has no automatic updates: download the new ZIP and extract it over the same folder.
• Uninstall: for the Store edition, right-click the app in the Start menu and choose Uninstall. For the ZIP edition, delete the extracted folder. The preview cache lives in %LOCALAPPDATA%\SSEM MarkdownEditor; delete that too.