Marco is a fast, cross-platform Markdown editor built in Rust with live preview, syntax extensions, and a custom parser for technical documentation.
Polo, its companion viewer, lets you open and read Markdown documents with identical rendering and minimal resource use.
Both run natively on Linux and Windows, built with GTK4 and Rust, designed for speed, clarity, and modern technical writing — with features like executable code blocks, document navigation, and structured formatting.
Marco - Full-featured Markdown editor with live preview
Polo - Lightweight Markdown viewer
Ready to try Marco? Installation is simple and takes less than a minute:
| Linux | Windows |
|---|---|
Download the latest .deb from the Releases page:https://github.com/Ranrar/Marco/releases/latest |
Download the latest .zip from the Releases page:https://github.com/Ranrar/Marco/releases/latest |
Asset: marco-suite_<version>_linux_amd64.deb |
Asset: marco-suite_<version>_windows_amd64.zip |
| Install (Debian/Ubuntu): 1. Download the *.deb asset for your architecture (typically amd64)2. Install with your package manager (e.g. dpkg), then resolve any missing dependencies if prompted |
Install: 1. Download the .zip asset2. Extract to any location (e.g., C:\Program Files\Marco)3. Run marco.exe or polo.exe4. Settings are stored in the extracted folder (portable mode) |
| Use Case | Marco (Editor) | Polo (Viewer) |
|---|---|---|
| Technical documentation & manuals | Yes | Yes |
| Research papers (math, footnotes, references) | Yes | Yes |
| Books & long-form writing | Yes | Yes |
| Presentations & slide decks | Yes | Yes |
| README & project documentation | Yes | Yes |
| Blog posts & articles | Yes | Yes |
| API documentation | Yes | Yes |
| Meeting notes & minutes | Yes | Yes |
| Knowledge base & personal wiki | Yes | Yes |
| Release notes & changelogs | Yes | Yes |
| Study notes & course material | Yes | Yes |
Marco aims for 100% CommonMark compliance (currently 652/652 spec tests passing), plus a practical set of focused extensions.
| Feature | Status |
|---|---|
| CommonMark core (headings, lists, code, links, images, blockquotes…) | Yes |
| International text (Unicode) + RTL text direction support | Yes |
| Tables (GFM) including headerless tables | Yes |
| Task lists and inline checkboxes | Yes |
| Strikethrough, highlight, superscript, subscript | Yes |
| Footnotes and inline footnotes | Yes |
| Admonitions / callouts (Note, Warning, Tip, custom) | Yes |
Emoji shortcodes (:joy:) |
Yes |
User mentions (@name[platform]) |
Yes |
| Math — KaTeX inline and block | Yes |
| Mermaid diagrams | Yes |
| Tab blocks | Yes |
| Slide decks | Yes |
| Heading IDs for stable anchors | Yes |
| GFM autolink literals | Yes |
| PDF export | Yes |
| Print preview with page settings | Yes |
| Table of contents (TOC) sidebar | Yes |
| Bookmarks and cross-file links | Yes |
| Scroll sync between editor and preview | Yes |
| Mode | Purpose | Status | Notes |
|---|---|---|---|
| Live Preview | Real-time rendered Markdown while you edit. | Available | Synced with editor, supports themes and interactive preview behaviors. |
| Print Preview | Paged, print-focused preview for PDF/export workflows. | Available | Uses paged media rules (paper size, orientation, margins, page numbers). |
| Code View | Inspect the underlying rendered HTML source. | Available | Useful for debugging markup/output structure. |
| Presentation View | Slide-style reading/presenting mode for documents and decks. | Planned | In progress for a future release. |
I started building Marco because I couldn't find a simple, reliable Markdown editor for Linux.
As an IT systems manager, I've always preferred local software — fast, safe, and running entirely on my own machine, not in the cloud.
In my daily work, I write a lot of technical documentation and manuals, so I needed a tool that could handle complex documents efficiently and reliably.
That idea became a personal challenge: to create a complete Markdown editor from the ground up — with a custom-built parser and a design focused on performance, clarity, and long-term potential.
Most Markdown editors focus on simplicity. Marco focuses on precision.
It's built for developers, engineers, and writers who need:
- Native performance — no login, no cloud, your documents stay on your machine
- Structured documents — full control over headings, blocks, and formatting
- Custom Markdown grammar — hand-crafted parser for extensibility and AST-level control
- Seamless preview — rendered with WebKit and perfectly synced with the editor
Whether you're writing technical docs, tutorials, or long-form text, Marco turns Markdown into a professional writing tool — fast, clear, and extensible.
-
GTK4-RS (
gtk4,glib,gio) - Cross-platform GUI toolkit powering windows, widgets, menus, and event handling. Used for Marco and Polo's native Linux/Windows interface. -
SourceView5 (
sourceview5) - Editor component with syntax highlighting and code-friendly text features. Powers the Markdown editing area (line numbers, search/replace, formatting aids). -
WebKit6 / WebView2 - HTML preview engine (
webkit6on Linux,wry/WebView2 on Windows). Renders live preview with local images, CSS themes, and scroll-sync interactions. -
nom (
nom) - Parser combinator library used for Marco's custom Markdown grammar. Enables recursive-descent parsing and AST generation incore/src/grammar/. -
RON (
ron) - Human-readable configuration format for settings, themes, and preferences. Easy to edit manually and friendly for version control. -
KaTeX (
katex-rs) - Rust implementation of KaTeX for math rendering. Supports fast native inline and block LaTeX output without browser JS dependencies. -
Mermaid (
mermaid-rs-renderer/mmdr) - Pure Rust renderer by Jeremy Huang. Supports 23 diagram types and can be 100-1400x faster thanmermaid-cli. -
Paged.js (
paged.js) - CSS Paged Media polyfill used in print-preview pagination. Project: pagedjs/pagedjs (MIT License). -
markdownlint - Marco uses an internal diagnostics catalog aligned with markdownlint-style rule IDs (MD*). Project: DavidAnson/markdownlint.
- Syntax highlighting in editor (via intelligence engine)
- Diagnostic underlines — issue detection with hover details and footer panel
- Hover insights — Markdown element info and diagnostic details at cursor
- Completion (in-progress: Markdown completions available; refinement ongoing)
- Enhanced AST validation and error reporting
- Optimize parser performance and caching
- Multiple layout modes: editor+preview, editor only, preview only, detachable preview
- Scroll sync between editor and preview
- Intelligent search
- Context menus & toolbar: Quick access to formatting and actions
- Syntax highlighting in editor
- Diagnostics (issue underlines, footer panel, hover details, reference dialog)
- Markdown hover insights
- Right-to-left (RTL) text direction support with live toggle
- Table auto-align — pipe tables reformatted on Tab/Enter/cursor-leave; manual via context menu or Ctrl+Alt+T
- Tools menu — live toggles for wrap, line numbers, invisibles, tabs, syntax colours, table auto-align, scroll sync, and text direction
- Multi-cursor editing support
- LSP protocol for language server integration
- Same viewer engine as Marco
- Local link prompt — click a
.mdlink in the preview to open it in Polo - Search function
- Mouse over link information
- Smart code blocks with programming languages syntax
- Math rendering: KaTeX support for equations and formulas (inline
$...$and display$$...$$) - Diagram support: Mermaid for flowcharts, sequence diagrams, class diagrams, and 20+ other diagram types
- Export to PDF
- Page size presets for export (A4, US Letter, etc.)
- Document navigation: TOC sidebar (collapsible, click-to-scroll, configurable depth)
- Document navigation: bookmarks
- Document navigation: cross-file links (local link prompt in preview)
- Document presentation mode
- Language plugin system via.
assets/language/xx*.tomlfiles - Local AI-assisted tools: writing suggestions, grammar checking, content improvement
- Collaborative editing (Yjs/CRDT): shared document model, multi-cursor, presence awareness
- Built in terminal to run code blocks in editor
- Cross-platform support: Linux and Windows builds
- Linux packaging: .deb packages
- Windows packaging: Portable .zip packages
- Additional packaging: Snap, .MSI installer
- Privacy-first telemetry (opt-in, disabled by default)
- Privacy guarantees: No personal data, no file content, no tracking cookies
- User control: First-run dialog, settings toggle, can be disabled anytime
- Data collected (anonymous, minimal):
- App launch events (to understand active user count)
- OS type (Linux/Windows) and app version
- Anonymous session ID (random UUID per session, not tied to user)
- Feature usage patterns (which menu items, view modes, export formats)
- Error/crash reports (stack traces only, no user content)
- Timestamp and timezone offset
- Purpose: Prioritize development on most-used features, fix critical bugs faster
- Transmission: Lightweight HTTPS endpoint, 3-second timeout, non-blocking
We welcome contributions of all sizes. Short workflow:
- Open an issue describing the change or bug you plan to address.
- Fork the repository and create a feature branch.
- Add tests where appropriate and keep changes small and focused.
- Run
cargo buildandcargo testlocally. - Open a pull request referencing the issue and describe the change.
Code style & expectations:
- Keep UI code in
marco/src/ui/and business logic incore/src/logic/. - Follow Rust idioms (use
Result<T, E>, avoid panics in library code). - Add unit tests and integration tests in
tests/when applicable.
If you'd like to make a high-impact contribution, consider one of these areas — open an issue first so we can coordinate:
- Collaborative editing (Yjs / CRDT): add a
marco/src/components/collab/backend that implements aCollabBackendtrait and provide in-process tests for concurrent patches and cursor sync. - AI-assisted tools: add a
marco/src/components/ai/interface for suggestions/edits; keep adapters off the UI thread and provide a small example implementation.
Reference locations for contributors working on components and translations:
- marco/src/components/ai/README.md — AI component guidance and interface notes
- marco/src/components/collab/README.md — Collaboration integration notes and references
- documentation/language.md — Localization provider contract and workflow
- assets/language/language_matrix.md — language implementation matrix
This project is developed with occasional help from AI tools (for example, Copilot-style code suggestions). AI can speed up prototyping and refactors, but:
- Changes are still reviewed by a human.
- Tests and linting are expected to pass before merging.
- If something looks "too magical to be true", please open an issue — bugs don't get a free pass just because a robot wrote the first draft.