rmdv

A native Rust markdown viewer, scriptable over an IPC socket.

Built with AI (Claude Code and Codex). A human sets direction, tests, and reviews. How this was built.

rmdv.mclee.dev · Download · MIT

rmdv (Rust Markdown Viewer) is a fast, read-focused desktop app for browsing folders of .md files. It renders Markdown, Mermaid diagrams, Graphviz DOT graphs, block LaTeX math, and JSON/YAML mind maps without Electron, an embedded browser, or a JavaScript runtime. On macOS and Linux, it can also open text PDFs as locally extracted Markdown via PDFium.

It also exposes a scriptable IPC socket. Any program or agent (Claude Code, Codex, Cursor, a shell script) can drive the running window through the rmdv CLI: open files, scroll to a section, switch view mode, dump state.

Why rmdv

rmdv is for reading a folder of Markdown files without starting a vault, an editor-first workflow, or a static-site build. It is a pure-Rust GUI built with Iced, with native Mermaid/DOT/LaTeX rendering and a machine-readable IPC control interface.

Features

• Workspace browser: open a folder, navigate the file tree sidebar
• Mermaid diagrams rendered natively, no JS, no browser
• Graphviz DOT diagrams rendered natively
• Block LaTeX math ($$…$$) via a pure-Rust layout engine (iced_math); no MathJax, no KaTeX
• Mind-map view (⌘M): any Markdown, JSON, or YAML document as a collapsible tree
• Full Mindmap workspace (⌘⇧M): navigate folders and files as a bounded, keyboard-first graph
• Native mindmap zoom: = / − / 0, mouse wheel, touch pinch, and macOS trackpad pinch
• PDF viewing: open a .pdf and read it as rendered Markdown; text extracted locally via liteparse (PDFium), no cloud, no LLM (macOS + Linux; view-only)
• Tree-sitter syntax highlighting: Rust, Python, JS, TS, Go, C, C++, Java, SQL, Bash, JSON, HTML, Markdown, and more
• Vault-wide search (⌘⇧F): Zed-style full-page results across every file in the workspace
• In-document search (⌘F)
• Command palette (⌘⇧P) and quick file finder (⌘P)
• Live reload: edits in your editor reflect instantly
• Edit mode (⌘E)
• Zen editing with unsaved-edit protection across navigation
• 10 built-in theme presets: One Light/Dark, GitHub Light/Dark, Solarized Light/Dark, Gruvbox, Nord, Dracula, and Tokyo Night, with system follow
• Keyboard-first: j/k/g/G and Home/End scroll the reader; ⌥⌘1–9 assigns the current file to a Quick Slot (it asks before replacing another file) and ⌘↑/⌘↓ cycles slots outside Zen, while Zen keeps Command arrows for native document motion; heading fold is ⌘K 0–6
• Auto-update: checks GitHub releases, SHA-256 verifies; signed + notarized on macOS
• CJK-friendly: bundled Inter + JetBrains Mono, system font fallback
• Drag and drop files or folders

Screenshots

Native Mermaid / DOT / LaTeX	Full Mindmap workspace (⌘⇧M)
Document Mindmap (⌘M)	Tree-sitter highlighting
Vault-wide search (⌘⇧F)	10 built-in theme presets
Live reload

More on rmdv.mclee.dev.

Install

macOS / Linux

Download the latest build from Releases:

• macOS Apple Silicon: rmdv_*_aarch64.dmg
• macOS Intel: rmdv_*_x86_64.dmg
• Linux x86-64: rmdv-*-x86_64.AppImage (chmod +x then run)

After opening the macOS app for the first time, use the CLI installation toast or run Install CLI from the command palette. This creates /usr/local/bin/rmdv, pointing to the binary inside the app bundle.

On Linux, launch the AppImage once and use the same toast or command-palette action. This creates ~/.local/bin/rmdv, pointing to the AppImage. Keep ~/.local/bin on your PATH if your shell does not already include it.

From source

git clone https://github.com/minchenlee/rmdv && cd rmdv
cargo build --release
./target/release/rmdv path/to/file.md

Requires Rust 1.95+. On Windows, build with cargo build --release --no-default-features; PDF text extraction is currently available on macOS and Linux only.

CLI / agent control

rmdv is single-instance. The first invocation opens a window and an IPC listener; subsequent invocations talk to it and return one-line JSON.

# open a file at a specific line
rmdv path/to/foo.md --line 42

# drive the running instance
rmdv goto --section "Install/Setup"
rmdv mode mindmap
rmdv current                          # prints JSON state

# stateless — no running instance needed
rmdv list-sections path/to/foo.md     # JSON array of headings
rmdv --pretty list-sections foo.md

Designed for coding agents (Claude Code, Codex, Cursor) to pull rmdv to the relevant section of a file without manual navigation. rmdv list-sections spec.md | jq works as a pure stateless command even when rmdv isn't running.

Keyboard shortcuts

Full Mindmap Mode (⌘⇧M) is an opt-in workspace navigator for seeing folders, files, and their structure as one graph. It is separate from document Mindmap (⌘M), so switching surfaces does not replace the document you are reading.

Key	Action		Key	Action
⌘P	File finder		⌘M	Document Mindmap
⌘⇧M	Full Mindmap workspace		⌘⌥W	Cycle Mindmap panel width
⌘R	Refresh current file / folder		⌘⌥R	Reveal file in Finder
⌘⌥C	Copy focused file path		⌘E	Toggle edit mode
⌘⇧P	Command palette		⌘S	Save
⌘O	Open folder		⌘T	Toggle theme
⌘B	Toggle sidebar		⌘K 0–6	Fold headings to level
⌘F	Search in document		⌘/	Shortcut cheatsheet
= / −	Mindmap zoom in / out		0	Reset mindmap zoom
⌘⇧F	Search whole vault		j / k	Scroll down / up
g / G	Top / bottom		Space / ⇧Space	Page down / up
⌘1–9	Activate Quick Slot 1–9		⌥⌘1–9	Assign file to Quick Slot 1–9
⌘↑ / ⌘↓	Previous / next slot (outside Zen)		⌘W	Close active slot
⌘⇧W	Close window		Esc	Exit Full Mindmap / close overlay

Historical performance benchmark

The following v0.2.0 measurements were taken on an Apple M2 MacBook Pro, median of five runs. Current builds may differ.

Metric	Value
Cold start to first paint	~150 ms
Parse a 10,000-line (~1 MB) document	8.1 ms

The renderer is viewport-aware: only blocks intersecting the visible viewport become widgets. Hot reload re-highlights only changed code blocks.

See docs/benchmarks.md for the full table and how to reproduce.

Demo

The demo/ folder is a sample vault exercising every feature: Mermaid, DOT, LaTeX, mind maps, nested folders, vault search. Open it with rmdv demo/.

Roadmap

• Code signing (mac notarization)
• Auto-update
• Export to PDF / HTML
• More tree-sitter grammars

How this was built

rmdv is written by AI: Claude (Anthropic) via Claude Code, with OpenAI Codex for some changes and for code review. The repository is open; read the code and judge it on its merits.

My role was direction, not authorship:

• Product direction: deciding what to build and why
• Testing: running the app, finding bugs, checking features behave
• Review: reading the generated code and the diffs before they land
• Measurement: the benchmark numbers above are real, taken on my own machine and reproducible from docs/benchmarks.md

I'm disclosing this because it's true and because the code should stand on its own. If something is wrong, open an issue.

Tech stack

Rust, with Iced for the GUI (pure native widgets, no webview), pulldown-cmark for Markdown parsing, and tree-sitter for syntax highlighting.

Area	Crate
GUI	iced
Markdown	pulldown-cmark
Syntax highlighting	tree-sitter + per-language grammars (rust, python, js, ts, go, c, cpp, java, sql, bash, json, html, md, yaml, toml)
Mermaid diagrams	merman + layout-rs
LaTeX math	iced_math (pure-Rust layout engine)
SVG rasterization	resvg
PDF text extraction	liteparse (PDFium)
Images	image
File watching	notify
HTTP (update + remote images)	reqwest
Async runtime	tokio
IPC	interprocess
CLI	clap

Acknowledgments

• Iced — the pure-Rust GUI toolkit rmdv is built on
• tree-sitter and its grammar authors — real-parser syntax highlighting
• pulldown-cmark, merman, resvg, liteparse — rendering and parsing
• Inter and JetBrains Mono — bundled fonts
• Claude via Claude Code — AI-assisted implementation
• Ferrite — a fellow AI-built Rust editor whose README inspired the disclosure here

License

MIT — see LICENSE.