A lightweight, fast Markdown viewer with Mermaid diagram support and live reload. Built in Rust.
Built for the LLM era. AI tools generate Markdown constantly — code documentation, technical specs, analysis reports — packed with diagrams, tables, and structured content. You need a fast way to read them.
Most developers end up previewing Markdown in VS Code, pasting into a browser, or squinting at raw text in the terminal. None of these handle Mermaid diagrams. None are instant. mdr is.
- One command —
mdr file.mdand you're reading, not editing - Native Rust binary — no Electron, no Node.js, no npm, starts in milliseconds
- Mermaid diagrams — flowcharts, sequence diagrams, pie charts rendered as SVG natively (no headless browser)
- Three backends — full GUI (egui), native webview (WebKit/WebView2), or terminal UI (TUI) over SSH
- Live reload — edit your file or let your AI tool regenerate it, see changes instantly
- In-document search — Ctrl+F /
/to find text across all backends
mdr offers multiple rendering backends, selectable at runtime:
| Backend | Stack | Strengths |
|---|---|---|
| egui (default) | Pure Rust GPU rendering | Single static binary, fast startup, cross-platform |
| webview | OS native WebView (WebKit/WebView2) | GitHub-quality HTML/CSS rendering, full CSS support |
| tui | Terminal UI (ratatui + crossterm) | Works over SSH, no GUI needed, keyboard-driven |
git clone https://github.com/CleverCloud/mdr.git
cd mdr
cargo install --path .# egui only (smaller binary, no WebView dependency)
cargo install --path . --no-default-features --features egui-backend
# webview only
cargo install --path . --no-default-features --features webview-backendbrew tap CleverCloud/misc
brew install mdrnix run github:CleverCloud/mdrDownload from the Releases page for macOS, Linux, and Windows.
# Open with default backend (egui)
mdr README.md
# Open with webview backend
mdr --backend webview README.md
# Open in terminal (TUI)
mdr --backend tui README.md
# Show help
mdr --help| Key | Action |
|---|---|
q / Esc |
Quit |
j / ↓ |
Scroll down |
k / ↑ |
Scroll up |
Space / PgDn |
Page down |
PgUp |
Page up |
g / Home |
Go to top |
G / End |
Go to bottom |
Tab |
Switch focus between TOC and content |
Enter |
Navigate to selected TOC heading |
/ or Ctrl+F |
Open search |
n |
Next search match |
N |
Previous search match |
- Full GFM support — tables, task lists, strikethrough, footnotes, autolinks
- Syntax highlighting — code blocks with language detection (via syntect)
- Mermaid diagrams — flowcharts, sequence diagrams, pie charts, and more (via mermaid-rs-renderer)
- Table of Contents — auto-generated sidebar from headings with click-to-navigate
- Live reload — file watching with 300ms debounce, updates on save
- Dark/Light theme — follows OS theme (webview backend)
Mermaid code fences are rendered as SVG diagrams:
```mermaid
graph TD
A[Input] --> B[Process]
B --> C[Output]
```Supported diagram types: flowchart, sequence, pie, class, state, ER, gantt.
Note: Diamond/decision nodes (
{text}) are not yet supported by the underlying renderer. Use square brackets as a workaround.
src/
├── main.rs # CLI (clap), backend dispatch
├── core/
│ ├── markdown.rs # GFM parsing (comrak) + CSS
│ ├── mermaid.rs # Mermaid → SVG rendering
│ ├── toc.rs # Heading extraction for TOC
│ ├── search.rs # In-document search
│ └── watcher.rs # File watching (notify, 300ms debounce)
└── backend/
├── egui.rs # egui/eframe backend
├── tui.rs # ratatui/crossterm TUI backend
└── webview.rs # wry/tao WebView backend
Requires Rust 1.75+.
# All backends (default)
cargo build --release
# Run tests
cargo test
# Run clippy
cargo clippysudo apt-get install libgtk-3-dev libwebkit2gtk-4.1-dev libxdo-dev libgl1-mesa-devPre-built binaries are available on the Releases page for:
- macOS (Apple Silicon + Intel)
- Linux (x86_64)
- Windows (x86_64)
To create a release, push a version tag:
git tag v0.1.0
git push origin v0.1.0MIT
Issues and PRs welcome at github.com/CleverCloud/mdr.