A single-file markdown viewer and editor that runs entirely in your browser. Select a local folder, browse your .md files, and preview or edit them — nothing is uploaded anywhere.
This was made as a simple solution to a simple problem I personally had. Entirely generated with Claude Opus 4.6 in Claude Code (I only provided spec for design and basic functionality).
Feel free to report a bug, suggest a change, or submit a pull request. All are welcome.
| Preview | Split View |
|---|---|
 |
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| Editor | Dark Mode |
|---|---|
 |
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| Mobile Preview | Mobile Sidebar | Mobile Editor |
|---|---|---|
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- Folder browsing — pick any local directory using the File System Access API
- Recursive or flat — optionally include subfolders
- Live preview — rendered markdown with syntax-highlighted code blocks
- Editor — write markdown with a formatting toolbar and keyboard shortcuts
- Split view — side-by-side editor and preview
- Search — filter files by name
- File management — create, rename, and delete files and folders
- Dark mode — light/dark theme toggle
- Responsive — works on desktop, tablet, and mobile
- State persistence — remembers your last folder, open file, theme, and view mode across reloads
Open index.html in a browser, or visit the hosted version:
https://flatdotcodes.github.io/simple-mk-web
Click "Open Folder" and select a directory containing markdown files. Your files never leave your device.
| Shortcut | Action |
|---|---|
⌘O |
Open folder |
⌘S |
Save file |
⌘N |
New file |
⇧⌘N |
New folder |
⌘\ |
Toggle sidebar |
⌘K |
Search files / Insert link (in editor) |
⌘1–5 |
Switch view mode |
⌘B |
Bold |
⌘I |
Italic |
? |
Show all shortcuts |
- A modern browser with File System Access API support (Chrome, Edge, Opera)
MIT