MarkViewer
Markdown viewer & editor for Mac
Open any .md file instantly
A free, native Markdown viewer and editor for macOS. Open .md files instantly, render GitHub-flavored Markdown, and edit with live WYSIWYG — fully offline, no setup.
— downloads worldwide
Key Features
Auto Table of Contents
Automatically generates a table of contents from document headings.
WYSIWYG Editing
Formatting is applied instantly as you type Markdown syntax.
GFM Support
Supports tables, checklists, and code syntax highlighting.
Lightweight & Fast
Launches instantly and uses minimal system resources.
100% Offline
Works completely offline. No internet connection required.
Native macOS App
Built specifically for macOS with Universal Binary support for Intel and Apple Silicon Macs.
Multi-tab & Multi-window
Open multiple files in tabs with ⌘T, new windows with ⌘N. Work on several documents at once.
File Finder & Terminal
Built-in file explorer and terminal. Browse files and run commands without leaving the app.
AI Review Loop NEW
Highlight passages, leave review comments inline, then hand off an editable prompt to Claude, ChatGPT, or any AI tool with one click (⌘⇧↵).
Work with AI, locally
Ask an agent to do the work, or review what an agent already wrote. MarkViewer drives the Claude Code or Codex CLI already installed on your Mac — no API key, no account, nothing leaves your device.
Ask Agent
Describe the change you want and let an agent do it. MarkViewer detects the Claude Code or Codex CLI on your Mac and runs the task there — no API key, no setup.
Annotate & Hand Off
Highlight what needs fixing and leave inline comments (⌘⇧R). Then resolve them with an agent in place, or hand off an editable prompt to any AI assistant (⌘⇧Enter).
Stays on Your Mac
Prompts, documents, and results never leave your device. The agent runs under your own CLI login, with no cloud sync and no browser tabs in the loop.
Review Before It Lands
The agent edits an isolated copy of your folder. You get a diff with the exact +/− counts, and your file stays untouched until you hit Apply.
For users who already work with AI tools
Claude, ChatGPT, Cursor, and Claude Code all output markdown. If you already work that way, MarkViewer adds an agent you can ask and a review layer you can trust — but the core app is just a fast Markdown viewer and editor. Use as much or as little of this as you want.
Bonus, not the main course. Fully optional, always local.
When to Use MarkViewer
Real scenarios from real users
Read GitHub Release Notes Offline
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
Quick Edits with WYSIWYG Preview
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
Read Local Documentation Offline
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
Why Choose MarkViewer?
MarkViewer is built for one specific job: being a fast, lightweight free markdown viewer for Mac. It's not trying to be a full-featured IDE or note-taking system. New to the format? See how to open MD files on Mac.
✓ MarkViewer is perfect when...
- • You just need to read a markdown file
- • You're checking release notes or documentation
- • You want offline-first, privacy-focused tools
- • You don't need a heavy IDE or complex features
- • You work with multiple markdown files in tabs
- • You need to review AI-generated file changes
Keyboard Shortcuts
⌘T New Tab, ⌘N New Window, ⌘W Close Tab, ⌘S Save
Resizable Panels
Drag to resize TOC panel, layout persists between sessions
Search & Highlight
Find text with visual yellow/orange highlighting and match navigation
macOS Native
Full integration with file dialogs and menus
Save Status
Auto-detect changes and save notifications
Markdown Paste
Paste markdown from external sources with formatting preserved
FAQ
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 reviewing AI-generated documents — specs, notes, and working docs. Unlike editors or IDEs, it focuses on the review step: read what AI wrote, annotate what needs changing, and hand off corrections. It launches instantly with zero setup.
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 10.15 (Catalina) 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.