MDPreview is a free, privacy-first browser-based Markdown editor with live preview. Write with syntax-highlighted code blocks and local document storage — all without a server, account, or signup. No data ever leaves your device.
- Live split-pane editing — CodeMirror 6 editor with instant Markdown preview
- Syntax highlighting — Markdown in the editor, code blocks in the preview via highlight.js
- Multi-document — Create, switch, rename, and delete files from the sidebar
- IndexedDB persistence — All documents survive page refreshes (no server storage)
- 8 color themes — Solarized Light/Dark, Folio, Ember, Monokai, Nord, One Dark, GitHub Light
- Focus mode — Hide everything except the editor for distraction-free writing
- Draggable splitter — Resize the editor and preview panes to your preference
- Export options — Download as
.md, copy Markdown source, or copy/download rendered HTML - Formatting toolbar — Bold, italic, headings, lists, blockquotes, links, and code blocks
- Status bar — Live word, character, and line counts with auto-save indicator
- Privacy-first — Runs entirely client-side; nothing is uploaded
- Offline-capable — Works without internet after initial load
- GitHub-Flavored Markdown — Tables, task lists, code fences, strikethrough, autolinks
- No account required — Open and start writing immediately
- No data upload — Everything stays in your browser
- Works offline — No internet dependency after page load
- Open source — MIT license, inspectable and auditable
- No backend — Static site, zero servers, zero databases
| Layer | Technology |
|---|---|
| Build tool | Vite |
| Text editor | CodeMirror 6 |
| Markdown parser | marked |
| Code highlighting | highlight.js |
| HTML sanitization | DOMPurify |
| Testing | Vitest + jsdom |
# Install dependencies
npm install
# Start the development server
npm run dev
# Build for production
npm run build
# Preview the production build
npm run preview
# Run the test suite
npm testYes. Once the page is loaded, MDPreview runs entirely client-side and continues working without an internet connection.
No. All documents are stored locally in your browser using IndexedDB. Nothing is ever sent to a server.
Yes. MDPreview is MIT-licensed. The source code is available on GitHub.
Yes. You can copy rendered HTML to your clipboard or download a complete standalone .html file with embedded syntax highlighting.
Yes. MDPreview supports GFM including tables, task lists, code fences with syntax highlighting, strikethrough, and autolinks.
Saving is automatic. MDPreview auto-saves to IndexedDB as you type — no save button needed.
MIT © 2026 Jonathan Au