⌂
Open files and folders
Open a single Markdown file or a whole folder. Browse your workspace from the sidebar and keep related notes together.
Simple · Desktop · Free
A simple Markdown editor with everything you need.
Simple MD makes writing and previewing Markdown feel straightforward. Open a folder or a file, switch between source, preview, split, and WYSIWYG modes, and use built-in tools for charts, math, and everyday editing.
robrighter/simple-md · ★ Star on GitHub
Why Simple MD
Easy to use. Ready for real notes.
Simple MD keeps the basics obvious and the useful extras close at hand: previews, tabs, folder browsing, math, charts, and a clean editing flow.
≡
Four view modes
Display, Text, Hybrid WYSIWYG, and Split views are built in, so you can write and review however you prefer.
∑
Math & charts inline
First-class KaTeX for inline and block LaTeX. Drop a fenced chart block of JSON and it renders as a real chart.
▸
Folder workspaces
Open a folder, get a real file tree. Right-click to rename, move, or delete — all changes go straight to the filesystem.
↗
OS file association
Set Simple MD as your default for .md, .markdown, .mdown, and .mkd. Double-click in Finder or Explorer — it just opens.
✦
On-device AI
An optional local AI assistant runs Gemma 4 entirely on your machine. Insert, replace, or append straight into the document.
↘
HTTPS import
Paste any HTTPS URL — including github.com/.../blob/... links — and Simple MD fetches the raw Markdown safely.
◔
Fast at scale
Built on CodeMirror 6 and ProseMirror. Big notes scroll smoothly; preview rendering stays off the typing critical path.
⌫
Lossless round-trip
Hybrid mode preserves your Markdown exactly. Edit visually, save, and your source stays clean.
Four ways to look at one file
One document. Four comfortable ways to work.
The active document is always front and center. Switch modes with the tabs in the top bar, or with a keyboard shortcut — your cursor and scroll position come along.
Display
Read-only render
Polished typography, GitHub-flavored Markdown, syntax-highlighted code, KaTeX math, and inline charts. Distraction-light reading and proofing.
Text
Raw Markdown source
Pure source editing in CodeMirror 6 with syntax highlighting, list continuation, and bracket matching. Power users feel right at home.
Hybrid
True WYSIWYG, lossless
Edit rich text directly while Markdown stays the source. Powered by Milkdown / ProseMirror with lossless round-trip.
Split
Source on the left, preview on the right
Type in raw Markdown and watch the rendered version update beside you. Synchronized scrolling, no fuss.
Inline charts
Charts that live inside your notes.
Drop a fenced chart block with a JSON spec and Simple MD renders it as a real Recharts visualization in
preview and hybrid mode — bar, line, area, and pie supported. It is a practical way to keep
small charts, notes, and source data together.
- JSON-backed, version-control friendly
- Series and axes inferred when omitted
- Errors render an inline panel — never throw
Optional AI assistant
Draft, rewrite, and apply edits faster.
The assistant can use the active document as context, then insert, replace, or append text directly in the editor. It is opt-in, runs on-device, and only downloads a Gemma model when you choose to enable it.
- Active document auto-attached as context
- Insert · Replace · Append straight into the editor
- Replace shows a side-by-side diff before committing
- License-gated by Google's Gemma terms · one-time
Math, done right
LaTeX that just shows up.
Inline $…$ and block $$…$$ render through KaTeX in
Display, Hybrid, and Split mode. No plugin to install, no server to reach, no shimmer
of "fetching fonts" — Simple MD bundles everything it needs.
- Inline and block math
- Friendly errors — bad LaTeX renders red, never breaks the doc
- Print-quality output for export to PDF or HTML
The full list
The Markdown features people actually use.
A quick checklist of what is built in today, from basic editing to richer notes with charts, math, tabs, and file associations.
- Display mode — read-only render with GFM, syntax highlighting, KaTeX math.
- Text mode — raw Markdown in CodeMirror 6 with syntax highlighting.
- Hybrid mode — true WYSIWYG via Milkdown / ProseMirror, lossless Markdown round-trip.
- Split mode — source on the left, rendered preview on the right.
- Folder workspaces — open a folder, browse the tree, edit in place.
- Right-click rename / delete — straight from the sidebar tree.
- Standalone file open — open one
.mdwithout adding its parent folder. - Tabbed editing — multiple documents open, drag to reorder.
- Scratchpads — unsaved drafts via the
+on the tab strip. - Recent files & workspaces — eight slots each, persisted locally.
- Inline charts — fenced
chartJSON renders as bar / line / area / pie. - KaTeX math — inline and block LaTeX, bundled offline.
- Code highlighting — fenced code blocks rendered with syntax colors.
- GitHub-flavored Markdown — tables, task lists, strikethrough, autolinks.
- HTTPS Markdown import — including auto-conversion of GitHub blob URLs.
- OS file association — default app for
.md,.markdown,.mdown,.mkd. - External file change banner — see and reload edits from other apps safely.
- Status bar — word, line, and character counts plus the current path.
- Local AI assistant — optional Gemma 4 E2B / E4B, runs entirely on-device.
- AI document mutation — Insert / Replace / Append assistant replies into the editor.
- Side-by-side replace preview — diff before destructive AI edits.
- Sandboxed remote fetch — HTTPS only, 10 MB cap, content-type validation.
- Sanitized preview HTML — no surprise script execution from untrusted Markdown.
- Cross-platform — macOS, Windows ARM64, and Windows x86_64 builds.
Download
Pick your platform.
Download the build for your computer and start editing Markdown files in a few clicks.
macOS
Universal · Apple Silicon & Intel
Native build for Apple Silicon (M1, M2, M3 and later). Ships as a signed zip — extract and run the included Install Simple MD.command.
Windows · ARM64
Windows on ARM
Native build for Surface Pro X, Copilot+ PCs, and other ARM-based Windows machines. No emulation, full speed.
Download for Windows ARM
Windows · x86_64
Windows Intel / AMD
For the rest of the Windows world: 64-bit Intel and AMD processors. Ships as a signed .exe installer.
On Linux? No prebuilt binaries yet — clone the repo and build it yourself. It's a
npm install && npm run tauri:build away.
View build instructions on GitHub
Looking for older builds, checksums, or release notes? See the releases page on GitHub.
Simple MD is open source.
Read the code, file an issue, send a pull request, or fork it and make it your own. The whole app — Rust backend, React frontend, build pipeline — lives at github.com/robrighter/simple-md.
Common questions
Quick answers.
The full guide lives in the docs — these are the questions people ask first.
What can I do with Simple MD?
You can write raw Markdown, preview it, edit visually in Hybrid mode, compare source and preview side by side, organize folders, use tabs, render math and charts, and open Markdown files directly from your OS.
Is Simple MD free and open source?
Yes — both. Simple MD is free to download and use on every supported platform, and the full source lives at github.com/robrighter/simple-md. Read the code, file an issue, send a pull request, or fork it.
Does the AI assistant send my notes anywhere?
The AI assistant is optional and runs on your computer. Simple MD bundles a tiny llama-server sidecar and downloads a Gemma 4 model file (E2B, ~5 GB, or E4B, ~2.5 GB) the first time you enable it.
If you never use the AI button, Simple MD works as a regular Markdown editor.
Can I use Simple MD without installing the AI?
Absolutely. The AI assistant is one button in the sidebar. Ignore it and Simple MD is a clean, fast, fully-featured Markdown editor. The model is only fetched the first time you accept the Gemma terms and pick a variant.
Does it work offline?
Yes. Editing, preview, charts, math, folders, and file operations work offline. Network access is only used for features that need it, like HTTPS import or downloading an optional AI model.
What about Linux?
Linux is in scope per the spec but not yet a published build. Tauri makes it cheap to ship — once macOS and Windows are stable, Linux .deb and AppImage bundles are next.
Do you collect telemetry?
Simple MD does not include analytics or crash reporting. It only makes network requests for actions you start, like HTTPS import or optional AI model setup.