v0.2.2 · Windows 10+ · free forever MDHero — free markdown viewer and editor for Windows

A markdown viewer and editor
Windows was missing.

A free, open source markdown viewer for Windows and a lightweight editor — small, fast, and native.

Under 8MB. The free markdown viewer Windows users actually want — a real .md file viewer that opens any markdown document with a double-click. Built with Tauri and Rust. Press Ctrl+E to edit and Ctrl+S to save — no accounts, no uploads.

Download for Windows View source
Requires Windows 10+ (64-bit). Installer is a standard .exe setup.

Why Windows users choose MDHero as their markdown viewer for Windows

Tiny footprint, zero bloat

Under 8MB installed — roughly 20x smaller than MarkText or VS Code. No Electron runtime, no bundled Node.js. Runs on Tauri and Rust for native Windows performance.

Proper code rendering

Syntax colors for 25+ languages that look sharp on any display. KaTeX for LaTeX equations, Mermaid for flowcharts. Themes follow your Windows light/dark preference.

Clean up AI output instantly

Copy from ChatGPT, Claude, or Gemini and paste into MDHero. LLM paste mode strips the escaped newlines and broken formatting so you can actually read the response.

Edit in place with Ctrl+E

Press Ctrl+E on any local file to flip into a focused editor. Ctrl+S saves to disk. Scroll position follows you between viewer and editor — line by line.

Ctrl+T, Ctrl+F, done

Familiar Windows keyboard shortcuts. Tabbed interface with drag-to-reorder, a Table of Contents sidebar for long documents, and pin your project folders for quick access.

Open .md files from Explorer

Set MDHero as the default handler to open .md files on Windows. Double-click any markdown document in Explorer to view it rendered. Also opens GitHub URLs and Claude Code plans.

Offline and private by design

Your files stay on your PC. Nothing is uploaded, no account is required, no usage data is collected. Works without an internet connection — ideal for air-gapped or corporate environments.

How MDHero compares on Windows

Most markdown viewers on Windows are either editors, Electron-based, or paid. MDHero is different.

MDHero Typora MarkText Markdown Monster MarkView
Price Free $14.99 Free $39 Free
Open source Yes No Yes No No
App size ~8MB ~90MB ~170MB ~80MB ~100MB
Viewer + editor Both Editor only Editor only Editor only Viewer only
Mermaid diagrams Yes Yes No Yes Yes
LLM paste mode Yes No No No No
Still maintained Yes Yes No (2022) Yes Yes
Install · Windows

First run takes one extra click. SmartScreen warning, bypass, done.

MDHero is open source and not signed with a Microsoft Authenticode certificate (that's $200–700/year from a certificate authority, which we haven't taken on yet). On first run, Windows SmartScreen shows a warning. Here's how to bypass it once.

Steps

  1. Download MDHero_0.2.2_x64-setup.exe (or the .msi if you prefer)
  2. Double-click the downloaded file
  3. Windows SmartScreen shows: Windows protected your PC. Microsoft Defender SmartScreen prevented an unrecognized app from starting.
  4. Click the small More info link in the dialog text
  5. A new button appears: Run anyway — click it
  6. Follow the installer steps (default settings are fine)
  7. MDHero is now in your Start menu and works normally
What's safe about this?
  • MDHero is fully open source — every line of code is on GitHub.
  • The Windows binary is built on GitHub Actions from public source on every release.
  • The "unrecognized app" warning is what Windows shows for any unsigned binary, including thousands of legitimate open-source apps.

More on opening markdown files on Windows

Guides and comparisons from the MDHero blog.

Guide

How to open .md files on Windows

Every reasonable way to view markdown on Windows 10 and 11 — Notepad, VS Code, Chrome, MDHero — compared.

 Roundup

Best free markdown viewers in 2026

The shortlist of free markdown apps for Windows, Mac, and beyond — with honest pros and cons.

 Tutorial

Fix ChatGPT paste formatting on Windows

Why AI output looks broken when you paste it, and how MDHero's LLM paste mode fixes it instantly.

Cross-platform user? See the Mac markdown viewer page, or browse all MDHero articles.

Free, open source, and built for Windows.

Download MDHero and start viewing markdown files in seconds.

Download for Windows

Also available for macOS.