20+ diagram types
Mermaid diagrams, drawn inline
Flowcharts, sequence, class, state and Gantt diagrams render where they sit in the file. No plugin, no browser tab, no internet.
NewReads what Claude Code, Codex and Cursor write
The Markdown viewer for Windows that keeps up with your AI.
MD Reader opens any .md file and re-renders it every time your agent saves: Mermaid diagrams, highlighted code and clean typography. Native, offline and light.
Windows 10 & 11 · Microsoft Store & Gumroad · One-time purchase
Claude Code✦Codex✦Cursor✦GitHub Copilot✦Windsurf✦Gemini CLI✦Aider✦Obsidian vaults✦GitHub READMEs✦Your own notes✦
Watch a plan write itself.
Your agent saves plan.md. MD Reader notices, re-renders in place and keeps you exactly where you were reading.
MD Readerplan.md
Auth refactor plan
Drafted by Claude Code, 14:02
Steps
- ✓Move session logic into
auth/ - Add silent token refresh
export async function refresh(token: string) {
const res = await fetch("/api/refresh", { method: "POST" })
return res.json()
}Risks
Token race when two tabs refresh at once. Add a lock.
Up to date · scroll position kept
Everything an AI-written doc throws at it.
Agents don't write plain prose. They write diagrams, checklists, tables and a lot of code.
plan.md saved14:02:07
plan.md saved14:02:11
plan.md saved14:02:16
Live reload that keeps your place
Every save re-renders instantly, and your scroll position stays put while the agent appends.
def ship(pr): return "merged"
Code you can actually read
Syntax highlighting for the languages your agent writes, with a copy button on every block.
Dark and light
Two carefully tuned themes. Follows Windows, or pick one.
✈ airplane mode: still works
Offline and private
Everything is bundled. No account, no cloud, and your files never leave your PC.
Double-click .md → opensDrag & dropOpen with…No Electron bundle
Fast to open, light on memory
Built on the WebView2 runtime Windows already has, instead of shipping its own browser. It stays out of the way of your IDE, terminal and agents.
Notepad shows you the syntax. This shows you the document.
Drag the handle. Same file, same second.
MD Reader · plan.md
Auth refactor plan
Drafted by Claude Code, 14:02
export async function refresh(token: string) {
const res = await fetch("/api/refresh", { method: "POST" })
return res.json()
}plan.md - Notepad
FileEditView
# Auth refactor plan
> Drafted by Claude Code, 14:02
## Steps
- [x] Move session logic into `auth/`
- [ ] Add silent token refresh
```mermaid
graph LR
A[Login] --> B{valid?}
B -->|yes| C[Dashboard]
B -->|no| D[Refresh]
```
```ts
export async function refresh(token: string) {
const res = await fetch("/api/refresh", { method: "POST" })
return res.json()
}
```⇆
NotepadMD ReaderMade by one developer who reads a lot of AI output.
I'm Kunal Sahu, an independent developer in India. I build native Windows tools, and my days now involve coding agents writing plans, specs and READMEs faster than I can read them in Notepad.
MD Reader is the viewer I wanted on Windows: open the file once, keep it beside the terminal, and read along as it's written, with the diagrams actually drawn. It's sold once, works offline, and every email to founder@happie.in reaches me directly.
One price. Yours to keep.
No subscription and no account. Join the list to lock in the launch price.
MD Reader for Windows · launch price
$9.99
One-time purchase, USD. Free updates through 1.x. 14-day refund policy.
Launch emails via Buttondown. Unsubscribe anytime. Privacy
- ✓Mermaid diagrams and syntax highlighting
- ✓Live reload for Claude Code, Codex and Cursor output
- ✓Dark and light themes
- ✓Works fully offline
- ✓Windows 10 and 11
- ✓Personal and commercial use
- Microsoft Store (soon)Gumroad (soon)
Guides for reading Markdown on Windows.
Questions, answered.
How do I open .md files on Windows?
Install MD Reader, right-click any .md file, choose "Open with" and pick MD Reader (tick "Always" to make it the default Markdown viewer). You can also drag a file onto the window or use File → Open.
Does it render Mermaid diagrams on Windows?
Yes. MD Reader is a Mermaid viewer for Windows as well as a Markdown reader: flowcharts, sequence diagrams, class diagrams, Gantt charts and the rest of the Mermaid syntax render inline, right where they appear in your document.
Is it a good Markdown reader for Claude Code, Codex and Cursor?
That's what it was built for. AI coding agents write plans, specs and READMEs as Markdown. Keep the file open in MD Reader and it live-reloads every time the agent saves, while keeping your scroll position, so you can read along as the document is written.
Does it work offline?
Completely. Rendering, diagrams and syntax highlighting are bundled with the app. There's no account, no sign-in and no cloud step, so your files never leave your PC.
Can I edit Markdown in it?
MD Reader is a viewer, on purpose. Keep writing in your editor or let your AI agent do it, and use MD Reader as the clean, always-up-to-date preview beside it.
How much does it cost, and where can I buy it?
The launch price is $9.99, paid once with no subscription. It will be available on the Microsoft Store and on Gumroad, and it runs on Windows 10 and Windows 11.
What is your refund policy?
If MD Reader isn't right for you, email within 14 days of a Gumroad purchase for a full refund. Microsoft Store purchases are refunded through Microsoft's own refund process, and we're happy to help.
Can I use it at work?
Yes. A single license covers personal and commercial use by one person on their own Windows PCs.
Will it slow my PC down?
It's built to stay light. MD Reader uses the WebView2 runtime that already ships with Windows instead of bundling its own copy of Chromium, so it opens quickly and stays small in memory next to your IDE and terminal.
When can I get it?
Early access opens soon. Join the list and you'll get the $9.99 launch price and a download link on day one.