The desktop reader for everything your AI writes. Equations come out typeset, Mermaid blocks become real diagrams, code gets highlighted, and your files never leave your machine.
ChatGPT, Claude and Copilot answer in LaTeX and Mermaid. Most Markdown readers show you the raw fences instead. Drag the handle to see the difference.
A display equation:
A Mermaid diagram block:
Drag the handle, click the track, or use the arrow, Home and End keys.
Read, Split and Edit, exactly like the app. Type into the editor below; the math and the diagram re-render as you go.
Every frame is SimpleMD 1.0.3 running on Windows, opening the kind of Markdown an AI assistant hands you. Flip the site theme and the app follows.
Everything you need to read and fix what an AI wrote, and nothing that gets in the way.
Inline $…$ and display $$…$$ math, typeset by KaTeX the moment the file opens. Fractions, integrals, matrices, all of it.
Flowcharts, sequence diagrams and class models drawn straight from ```mermaid blocks, as crisp vectors that follow your theme.
The editor behind modern code tools: line numbers, find and replace, bracket matching and Markdown highlighting. Fix the AI's typo, press Ctrl+S, done.
A heading outline that jumps you through long documents, and instant search across every file in the folder you opened.
Press Ctrl+P for a clean A4 PDF with the equations, diagrams and code exactly as you see them.
Open a whole folder at once, no import step. Pick Sans, Serif or Mono, set the reading width and accent, and switch light or dark.
A Markdown file from the internet should never be able to touch your computer. SimpleMD treats every document as untrusted.
Every embedded HTML tag or raw SVG is stripped of onerror, onload, and executable script payloads before touching the DOM.
The page that shows your document is sandboxed with no Node access, and a strict Content-Security-Policy allows only the app's own scripts. It can only read the files and folders you opened.
Saves go to a hidden temporary file in the same folder, then are renamed over the original, so a crash mid-write cannot leave a truncated file.
Open a file. Read. Write. Nothing else.
No accounts. No telemetry. No cloud. No AI rewriting your notes. SimpleMD does one thing, showing your Markdown beautifully, and gets out of the way.
Pick the installer or the portable build. Both are free and open source, and not one antivirus engine on VirusTotal flagged either file.
Installs SimpleMD for your user account, with a Start Menu shortcut and a standard uninstaller.
No installation required; run directly from any folder or USB drive.
Why this happens: SimpleMD is a free, open-source project and is not code-signed, because signing certificates cost money the project does not spend. Windows SmartScreen warns about any unsigned app that has not yet built up download reputation.
Verify the download yourself:
The scan reports above match these exact checksums. You can also read every line of the source on GitHub and build it yourself.
Free for Windows 10 and 11. Install it in under a minute and open the folder your AI has been filling up.
Download for Windows
