Write beautifully. Save everything as Markdown.
MDX feels like a polished document editor, but every note stays a clean
.md file you fully own. Local, fast, private, and ready for serious notes.
macOS · Windows · Linux · 14-day free trial
Everything you need, nothing you don't.
WYSIWYG editing
See formatted text as you type. No raw markdown to wrestle with.
Plain .md files
Your notes stay yours, in plain Markdown. Open them in any other editor any time.
Vault-based
Point MDX at a folder. The whole tree becomes a navigable workspace.
Math, diagrams, tables
First-class KaTeX, Mermaid, tables and task lists out of the box.
Optional AI assist
Bring your own OpenAI key. Suggestions stay local; nothing is proxied through us.
Local-first & private
Your files never leave your computer. No telemetry inside the app.
Built for notes that should outlive the app.
Open a folder
Use your existing notes directory as a clean, navigable workspace.
Write visually
Format lists, tables, math and diagrams without leaving the editor flow.
Keep the files
Every document remains a normal .md file you can version, sync or move.
One price. Yours forever.
A single payment. All updates within the major version included. Sales handled by Lemon Squeezy as merchant of record — VAT and sales tax included where required.
- Full WYSIWYG editor with Math, Mermaid, Tables
- Use on up to 3 devices
- Free updates within the major version
- 14-day refund, no questions asked
Or try free for 14 days first.
Frequently asked questions
Where are my files stored?
On your computer, in a folder you choose. MDX never uploads them anywhere.
Which platforms are supported?
macOS (Apple Silicon and Intel), Windows, and Linux.
Is there a free trial?
Yes — 14 days, full functionality, no credit card.
Can I use my license on more than one device?
Yes, on up to 3 devices you own. You can deactivate a device any time.
Refunds?
14-day refund, no questions asked. Email support@hellomdx.com.
How do AI features work?
You provide your own OpenAI API key in settings. Requests go directly from the app to OpenAI; we never see them.