Write Markdown.
Render everything.

A browser-based markdown editor with live preview, Mermaid diagrams, LaTeX math, and syntax highlighting. Free, no account required.

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untitled.md — merMDitor
# System Design
 
This is **merMDitor**, a markdown editor.
 
## Architecture
 
```mermaid
graph LR
  A[Editor] --> B[Renderer]
  B --> C[Preview]
```
 
$$E = mc^2$$
 
- [x] Set up project
- [ ] Write docs
System Design
This is merMDitor, a markdown editor.
Architecture
mermaid
Editor
→
Renderer
→
Preview
E = mc²
✓ Set up project
​ Write docs
What's included

Everything you need, nothing you don't

No plugins. No setup. Works in the browser.

Markdown
Full CommonMark with tables, task lists, footnotes, highlights, subscript, superscript, and emoji.
Mermaid Diagrams
Flowcharts, sequence, Gantt, class, and state diagrams — rendered live as you type.
LaTeX Math
Inline $x^2$ and block $$...$$ math via KaTeX.
Live Split Preview
Side-by-side editing with synchronized scrolling. Toggle either pane independently.
Import & Export
Open .md files from disk, export as Markdown, or print to PDF with configurable page settings.
Auto-save
Content is persisted to localStorage automatically. Reopen the browser and your work is there.