A split-screen Markdown editor that lives in your browser tab.
Write Markdown on the left and watch it render live on the right — with line numbers, syntax-highlighted code, Mermaid diagrams, and multiple documents in tabs. Export to Markdown, HTML, PDF, or plain text.
Everything runs locally. Nothing you write ever leaves your device.
My Private Writer is a split-pane Markdown editor. The left pane is your raw Markdown
source (with line numbers); the right pane shows a live, rendered preview that updates as you type. A
toolbar inserts Markdown syntax for you, and a tab bar lets you keep several documents open at once. Code
blocks are syntax-highlighted, mermaid code blocks render as diagrams, and all rendered HTML
is sanitized for safety. Your documents autosave to this browser and never reach a server.
Type Markdown in the left pane. The preview on the right refreshes automatically. Use the toolbar buttons (or shortcuts) to insert formatting without remembering the symbols.
Click Open to load a .md, .markdown, or .txt file. It opens in a new tab.
All open documents are saved to your browser automatically and restored when you return.
| Action | How |
|---|---|
| New document | Click the + in the tab bar (or Ctrl/⌘ + T). |
| Switch document | Click its tab. |
| Rename | Double-click a tab and type a new name. The name is used as the export filename. |
| Close | Click the × on a tab. You are warned if it has content. |
Each button inserts Markdown into the source pane, wrapping your current selection where it makes sense.
| Button | Inserts |
|---|---|
H1 H2 H3 | Heading prefixes (#, ##, ###). |
| B / I / | Bold **…**, italic *…*, strikethrough ~~…~~. |
</> | Inline code `…`. |
•≡ / 1. | Bullet and numbered lists. |
| ❝ | Blockquote. |
{ } | Fenced code block. |
| 🔗 / 🖼 | Link and image (prompts for URL). |
| ▦ | A starter Markdown table. |
| 📊 | A starter Mermaid diagram block. |
| ― | Horizontal rule. |
Put a language after the opening fence and code blocks are colour-highlighted in the preview, e.g.
```js, ```python, ```html. Without a language, highlight.js
auto-detects one.
A fenced block tagged mermaid renders as a diagram. Click the 📊 toolbar button for a starter
flowchart, or write your own:
```mermaid … flowchart TD; A-->B … ```
Mermaid also supports sequence diagrams, Gantt charts, pie charts, class diagrams and more. If a diagram has a syntax error, the preview shows the error inline so you can fix it.
Click Export ▾. Files are named after the active document's tab title.
| Format | What you get |
|---|---|
Markdown .md | Your raw Markdown source — clean and portable. |
HTML .html | A complete styled page, including rendered diagrams and highlighted code. |
Plain text .txt | Just the words from the rendered document, no markup. |
| Opens the browser print dialog on the rendered preview — choose Save as PDF. |
Standard Markdown has no syntax for text alignment, so My Private Writer leaves it out to keep every export clean and portable. If you need aligned layouts and other visual styling, reach for My HTML Editor instead, which is built for hand-tuning HTML where alignment and layout are fully supported.
| Shortcut | Action |
|---|---|
Ctrl/⌘ + B | Bold |
Ctrl/⌘ + I | Italic |
Ctrl/⌘ + K | Insert link |
Ctrl/⌘ + T | New document tab |
Ctrl/⌘ + S | Export as Markdown |
Ctrl/⌘ + O | Open a file |
Tab | Insert two spaces (in the editor) |
My Private Writer processes everything locally in your browser — no data is transmitted to any server.
Open documents are stored in localStorage and never leave your device. Rendered HTML is run
through DOMPurify to strip any malicious markup before it is shown, so opening Markdown
from untrusted sources is safe. Clearing your browser data removes saved documents, so export anything you
want to keep.
.md · .markdown · .txt
Technologies used:
Built with: