MDViewer

Press Space on any .md, .json, or .mermaid file in Finder to see it fully rendered — without launching an app. Column view, icon view, full-screen Quick Look. The extension installs automatically with MDViewer.

Flowcharts, sequence diagrams, ER diagrams, Gantt charts — all render as interactive SVGs right inside your document. Click any diagram to open a full-screen lightbox with zoom and pan. Adapts to light and dark mode automatically.

Built with SwiftUI from the ground up. MDViewer launches instantly, uses a fraction of the memory, and feels like a macOS app should — native fonts, system integration, smooth animations. Full GitHub Flavored Markdown: tables, task lists, code blocks, strikethrough.

Press ⌘⇧E to save any document as a clean PDF. Smart pagination keeps tables, code blocks, images, and diagrams intact across page breaks. Headings stay with their content — no orphans. Portrait or Landscape orientation right in the save dialog.

Open .json files directly — MDViewer renders them as an interactive tree with collapsible nodes, just like browser DevTools. One-click {} Format button pretty-prints the file while preserving key order.

Fenced code blocks render with color highlighting for 180+ languages — Python, JavaScript, Swift, TypeScript, SQL, and more. GitHub-style theme that adapts to light and dark mode.

Double-click any word to open the editor — cursor lands exactly where you clicked. Write, fix, restructure, then press ⌘S to save or Esc to return to reading. No app switching, no hunting for your place.

Browse the full commit history of any file right inside the sidebar. Click a commit to see a color-coded unified diff with line numbers. One click back to Current — no terminal needed.

Inline math with $...$ and display math with $$...$$ render beautifully with KaTeX. Matrices, fractions, integrals, Greek letters — everything you need for technical documentation and academic notes.

Follows your macOS system preference automatically. Every element adapts — code blocks, Mermaid diagrams, tables, the sidebar, and even the status bar. Easy on the eyes at any hour.

Find text across headings, code blocks, tables, and body text. All matches highlight in yellow, current match in orange. Works in both preview and editor modes. Counter shows "2 / 7" and updates live as you type.

A smart table of contents tracks your position as you scroll, highlighting the active section in real time. Click any heading to jump there instantly. Switch to the file tree to browse your project — rooted at the git repository, with the current file highlighted.

Set MDViewer as the default app for .md files in one click. Double-click in Finder or run open README.md in the terminal — it opens right here. Open multiple files as tabs, drag and drop folders. Always ready.