A native macOS app for viewing and editing markdown files. WYSIWYG editing meets lightweight design. Just open, edit, preview, and save. Your files stay local.
Automatically generates a table of contents from document headings.
Formatting is applied instantly as you type Markdown syntax.
Supports tables, checklists, and code syntax highlighting.
Launches instantly and uses minimal system resources.
Works completely offline. No internet connection required.
Built specifically for macOS with Universal Binary support for Intel and Apple Silicon Macs.
Open multiple files in tabs with ⌘T, new windows with ⌘N. Work on several documents at once.
Find text with yellow and orange visual highlights. Navigate between matches instantly.
Built-in file explorer and terminal. Browse files and run commands without leaving the app.
Highlight passages, leave review comments inline, then hand off an editable prompt to Claude, ChatGPT, or any AI tool with one click (⌘⇧↵).
AI tools generate markdown. You need a fast way to review and edit their output.
AI assistants generate long markdown responses. MarkViewer's auto table of contents lets you navigate AI-generated docs instantly.
Ask Claude to write documentation → Save as .md → Review in MarkViewer → Make quick edits → Done. No heavy IDE needed.
Downloaded AI-generated markdown? Review it offline without browser tabs, cloud sync, or internet connection.
When an AI coding agent modifies your file, MarkViewer auto-detects the change and shows a diff banner. Review, Accept, or Dismiss with one click.
Claude Projects stores knowledge as markdown files. ChatGPT outputs complex responses in markdown format. GitHub Copilot Workspace uses markdown for planning. AI coding agents like Claude Code and Cursor modify your markdown files directly — MarkViewer detects these changes and shows a diff for review.
MarkViewer is purpose-built for this new workflow: fast viewing, quick editing, zero setup.
Real scenarios from real users
Download release notes from GitHub. Open in MarkViewer for a clean, formatted view with table of contents. Review breaking changes and new features without switching browser tabs.
For: Software teams, product managers, engineers
Writing a README or documentation? Edit markdown with instant WYSIWYG formatting. See changes as you type. Fix typos, update sections, and save—all without launching a heavy IDE.
For: Developers, writers, bloggers, students, anyone editing docs
Working on a flight or with unreliable internet? Open local markdown documentation. MarkViewer's table of contents makes navigation easy. Everything works offline, no web server needed.
For: Remote workers, frequent travelers, students
MarkViewer is built for one specific job: fast, lightweight markdown viewing. It's not trying to be a full-featured IDE or note-taking system.
⌘T New Tab, ⌘N New Window, ⌘W Close Tab, ⌘S Save
Drag to resize TOC panel, layout persists between sessions
Find text with visual yellow/orange highlighting and match navigation
Full integration with file dialogs and menus
Auto-detect changes and save notifications
Paste markdown from external sources with formatting preserved
Yes, MarkViewer is completely free. There are no paid tiers, subscriptions, or hidden costs. Download and use it forever.
Yes, MarkViewer works 100% offline. All files are processed locally on your Mac. No internet connection required, no cloud sync, and your documents never leave your computer.
MarkViewer supports GitHub Flavored Markdown (GFM) including tables, task lists, code blocks with syntax highlighting, and standard markdown syntax. It handles .md and .markdown files.
Yes. Download release notes as .md files from GitHub and open them in MarkViewer for a clean, formatted reading experience. Great for checking changelogs and release details offline.
MarkViewer is purpose-built for reading and quick previewing, not heavy development or note-taking. It's lightweight, launches instantly, and doesn't require workspace setup. Think of it as Preview.app for markdown files.
No. MarkViewer has no cloud features, no accounts, and no sync. It's a local-only app. Your files stay on your Mac, exactly where you saved them.
MarkViewer requires macOS 10.13 (High Sierra) or later. It's a Universal Binary that runs natively on both Intel and Apple Silicon Macs.
Yes. MarkViewer supports multi-tab editing with ⌘T to open a new tab, ⌘W to close a tab, and ⌘N to open a new window. You can work on multiple markdown files simultaneously without switching between separate windows.
Yes. MarkViewer automatically detects when a file is modified externally — for example, by an AI coding agent like Claude Code or GitHub Copilot. It shows a diff banner so you can review, accept, or dismiss the changes.
Absolutely. MarkViewer processes everything locally on your device. Your markdown files never leave your computer. The desktop app includes optional, opt-in analytics (disabled by default) to help improve the product. The website uses standard analytics to understand usage. No personal information is collected. See our Privacy Policy for full details.
MarkViewer