MDeX v2.2.1 (macOS · Windows · Linux · Tauri v2)

MDeX · pronounced "em-dex" (/ˌemˈdɛks/) — the letter M followed by "dex", two syllables.

A multilingual Markdown reader & editor focused on privacy and AI assistance. Every file is processed locally — no network, no uploads, no cloud sync, no ads, no telemetry, by default; atomic (crash-proof) saves prevent data loss on crash or power outage. Since v2.0, MDeX also offers optional AI-assisted editing — and it can stay fully offline: a local model (e.g., Ollama) needs no internet; only an online AI service (OpenAI / DeepSeek / Anthropic / GLM / Gemini / Kimi, etc.) makes a request, and only when you configure and trigger it.

• A single self-contained HTML frontend (no Vue / React); Tauri v2 provides only the native shell (windows, menus, file dialogs).
• Zero runtime network requests: marked / KaTeX / highlight.js / DOMPurify / mermaid / jsPDF / html2canvas-pro / turndown / @retorquere/bibtex-parser and all KaTeX woff2 fonts are inlined / base64-embedded into a single index.html.
• Supports .md / .markdown / .html; can be set as the default .md handler — double-click to open.

🌐 Languages

The interface ships in 17 languages: English, 简体中文, Français, Deutsch, Español, Português, Italiano, Русский, 日本語, 한국어, العربية, हिन्दी, ਪੰਜਾਬੀ, Tiếng Việt, Bahasa Indonesia, اردو, Монгол (Кирилл).

• Switch at any time from the toolbar's language menu; your choice is remembered across sessions.
• Arabic is rendered right-to-left (RTL) automatically — body text, headings, list markers and the whole toolbar mirror to the right; embedded code blocks, LaTeX math, English terms and version numbers stay left-to-right, never mirrored.
• This README is itself translated into all 17 languages — use the selector at the very top of this page.

✨ Features

• Multi-tab + multi-window: open several files at once; unsaved changes are marked with a dot, and you are asked before closing; middle-click a tab to close it. Double-clicking a .md opens its own window (one file per window); double-clicking a file already open focuses that window instead of reopening it.
• Live split preview: drag the divider to resize; the toolbar button cycles Split / Editor / Preview.
• Click-to-position: click in the editor to scroll the preview; click in the preview to jump the cursor in the editor.
• Search & replace: find, replace one or all, with match count.
• Math: inline $…$ and block $$…$$ (also \(...\), \[...\]), rendered by KaTeX; long equations wrap at operators or auto-shrink.
• Code highlighting: language auto-detected; large docs lazy-highlight by viewport to stay smooth.
• Mermaid diagrams: a ```mermaid block renders as flowchart / sequence / class / state / Gantt / pie, etc.; click a diagram to open a standalone zoom / pan / fullscreen viewer window that updates live as you edit.
• Images: paste / drop / pick — saved to a <filename>_images/ folder next to the doc with a clean relative reference (no inline base64); drafts use a temp folder migrated on save; Save As flattens images into the target; centered by default.
• Font zoom: zoom the editor and preview fonts independently (−/percentage/+ controls, or ⌘/Ctrl + =/−/0); persists across restarts.
• Tables: GFM tables; narrow tables are centered to content, wide ones scroll horizontally without clipping.
• Citations (BibTeX): [@key] / \cite{key} syntax, numeric style; a References list is generated at the end, with two-way jumps between in-text [n] and the entry; supports an embedded ```bibtex block or a separately loaded .bib.
• HTML support: open .html files for rendering; convert between HTML and Markdown.
• Theme / language: dark / light, 17 UI languages (中文, English, Français, Deutsch, Русский, Italiano, 日本語, 한국어, Español, Português, العربية, हिन्दी, ਪੰਜਾਬੀ, Tiếng Việt, Bahasa Indonesia, اردو, Монгол (Кирилл) — Arabic & Urdu auto right-to-left).
• Auto-draft: content is saved periodically and restored after an unexpected close / crash.
• Word count: the status bar shows characters / lines / words live, plus the current row & column.
• Drag-and-drop: drop a .md file onto the window to open it; drop an image to insert it.
• Export: save as Markdown / HTML / PDF (vector) / LaTeX.
• Text color: toolbar palette wraps the selection in <span style="color:…">.
• AI-assisted editing: select some text and press ⌘/Ctrl + J (or the toolbar button) to have AI refine, expand or re-tone it; works with online services (OpenAI / DeepSeek / Anthropic / GLM / Gemini / Kimi, etc.) and with a local model such as Ollama for fully offline use; the result is previewed before it replaces the original, and the API key is stored only locally.
• Back / Forward: unified history across documents and cursor positions; ◀ ▶ buttons, Alt+←/→.
• Follow links: click a link in the preview to open the target in a new tab (http links in the system browser); the current document is never replaced.

⌨️ Shortcuts

Use ⌘ on macOS, Ctrl on Windows / Linux.

With multiple windows open, shortcuts only affect the focused window. When the image viewer window is open, ⌘/Ctrl + =/−/0 zooms the image instead.

📝 Cheat sheet

Markdown: headings # / ## / ###, bold **text**, italic *text*, strikethrough ~~text~~, inline code `code`, code blocks (triple backticks, with optional language), quote > text, lists - / 1., task list - [ ] / - [x], link [text](url), image ![alt](url), divider ---, tables | A | B |.

Math: inline $E = mc^2$; block $$\int_0^1 x\,dx$$ (may span lines). Uses LaTeX syntax, rendered by KaTeX; $ inside code blocks is not treated as a math delimiter. Supports align / aligned, matrices, cases and other common environments.

Citations: write [@key] or [@a; @b] in the text (LaTeX-compatible \cite{key}), embed the library via a ```bibtex block or load a .bib with the "Refs" button. A References list is generated at the end; in-text [n] is clickable.

📤 Export (Save As)

Click "Save As" and pick a format:

• Markdown (.md): save the source and update the current tab's name / path.
• HTML (.html): self-contained HTML with inlined CSS + code highlighting; math kept as $…$ literal, auto-rendered by inlined KaTeX.
• PDF vector: system print dialog, vector output, crisp at any zoom. Choose "Save as PDF".
• LaTeX (.tex): converted to a compilable .tex source (with documentclass and packages; math kept as-is). Exports a copy.

🔒 Offline & security

• Zero runtime network requests. The build output dist/index.html is self-checked: no src= / href= / url() / @import external links.
• Strict CSP (local IPC only, no WAN); all files are read/written locally, nothing uploaded.
• Verify: turn off Wi-Fi / unplug the cable and launch — math, images, code highlighting and Mermaid all work.
• dist/index.html still shows ~a dozen https://github.com/… strings; these all live inside license / source comments of marked / highlight.js etc. — plain text that never triggers a request; left intact to respect the open-source licenses.

📦 Installation

Prebuilt downloads

Download the installer for your platform from either source:

• GitHub Releases: https://github.com/fwzheng/mdex/releases
• Mirror site: https://www.spinss.cn/

macOS (.dmg, universal arm64 + x86_64), Windows (.exe, NSIS installer), Linux (.deb / .rpm / .AppImage).

Opening the unsigned app on macOS (bypass Gatekeeper)

This app is not developer-signed / notarized (offline scenarios usually can't notarize online). On macOS 12+, especially macOS 26 (Tahoe), launching it straight from the .dmg — or a freshly copied build — fails with "MDeX.app is damaged and can't be opened." That's Gatekeeper, not real damage. Fix in Terminal:

1. Drag MDeX.app out of the .dmg into /Applications first — never run it directly from the dmg (that triggers App Translocation and the com.apple.provenance attribute, the real cause of "damaged" on macOS 26).
2. Clear attributes and re-sign:

   xattr -cr /Applications/MDeX.app
   codesign --force --deep --sign - /Applications/MDeX.app

   com.apple.provenance is SIP-protected and can't be removed even with sudo; re-signing resets the signature so Gatekeeper lets it run. spctl still reports rejected for ad-hoc signing — expected, and it does not block open.

3. Launch with open /Applications/MDeX.app (or double-click). The first launch may still prompt once — confirm via System Settings → Privacy & Security → Open Anyway, or right-click the app → Open.

🛠️ Build from source

Source code: https://github.com/fwzheng/mdex. One-time setup: npm install → npm run fetch (downloads vendor with an integrity lock) → npm run build:html (inlines vendor + src/app.js into dist/index.html) → cargo tauri dev / cargo tauri build. Tests: npm test (frontend) · npx tsc --noEmit (types) · cd src-tauri && cargo test --lib (backend).

📁 Project structure

markdown/
├── app-shell.html          # frontend shell (HTML+CSS); app logic in src/app.js (+ i18n.js/help.js data)
├── src/
│   ├── app.js              # application logic (// @ts-check; inlined into dist by build-html.mjs)
│   ├── i18n.js            # 17-language UI strings (pure data; window.I18N, split from app.js)
│   ├── help.js            # help-document data (HELP_STRINGS + SK/sc/CITE_HELP_*, window.HELP_DATA)
│   └── globals.d.ts        # vendor / Window type declarations for type-checking
├── tsconfig.json           # type-check config (`tsc --noEmit`; no bundler)
├── tools/
│   ├── fetch-vendor.mjs    # one-time: download deps into vendor/ + integrity lock (online only here)
│   ├── build-html.mjs      # inline vendor + src/app.js + i18n.js + help.js into dist/index.html (KaTeX fonts → base64)
│   └── test-pure.mjs       # frontend pure-function tests (`npm test`)
├── dist/index.html         # build output: self-contained single file (Tauri frontendDist)
├── vendor/                 # download cache + integrity.json (.gitignore)
├── package.json            # @tauri-apps/cli + typescript(dev) + scripts
└── src-tauri/
    ├── Cargo.toml          # tauri 2 + dialog / single-instance + encoding_rs
    ├── build.rs            # tauri_build::build()
    ├── tauri.conf.json     # 1200×750 window, strict CSP, icons, .md association, menu hooks
    ├── capabilities/default.json
    ├── icons/              # full icon set from `cargo tauri icon`
    └── src/{main.rs, lib.rs}   # menus + file IO + multi-window routing + atomic write / file ownership

🎨 Customization

📄 License

This project's own code is open-sourced under the Apache License 2.0.

Third-party components: the project uses some third-party components (including but not limited to marked, KaTeX, highlight.js, DOMPurify, jsPDF, html2canvas-pro, turndown, mermaid, @retorquere/bibtex-parser, and Tauri, etc.); their copyright and license notices are detailed in the respective source files. These components are respectively licensed under MIT, BSD-3-Clause, Apache-2.0, MPL-2.0, and other open-source licenses.

Distribution requirements: under the Apache-2.0 license, redistributing this project requires retaining the LICENSE and NOTICE files; if you modify any source file, you must clearly indicate the changes in the corresponding file.

📬 Contact

For problems or suggestions: 郑法伟 (Fawei Zheng) fwzheng@bit.edu.cn