Native Quick Look previews
Registers as a macOS Quick Look extension so you can preview Markdown files from Finder with Space, using the system preview flow instead of opening an editor.
showmd
showmd is a free, open-source macOS Quick Look extension for previewing Markdown files in Finder with rendered output, dark mode, and source toggle.
Overview
showmd is a native macOS Quick Look extension for previewing Markdown files in Finder. It is positioned as a more readable way to view .md files than the built-in Preview app, with rendered Markdown instead of raw source text.
The preview includes support for YAML frontmatter, a rendered/source toggle, dark mode, syntax highlighting, math, Mermaid diagrams, inline images, and several Markdown-related file extensions. The site says it is open source, free, and requires macOS 26 (Tahoe) or later.
Features
Frontmatter rendering
Renders YAML frontmatter as a collapsible metadata table, collapsed by default, so file metadata stays available without taking over the preview.
Rendered/source toggle
Lets you switch between rendered Markdown and the raw source, and copy the file as HTML from the rendered view.
Full Markdown rendering
Supports GitHub Flavored Markdown, including tables, task lists, strikethrough, fenced code blocks, alerts, footnotes, autolinks, and more.
Syntax highlighting
Renders code blocks with language-aware syntax highlighting and supports more than 190 languages out of the box.
Rich preview content
Handles inline and block LaTeX math, Mermaid diagrams, relative images, and common Markdown-related file extensions such as .md, .markdown, .mdx, .mdc, .rmd, and .qmd.
Use Cases
Browse Markdown files in Finder
Preview .md files in Finder with a rendered layout, so you can scan content quickly without opening a separate editor.
Read instruction files more clearly
Inspect AI prompt files such as AGENTS.md, CLAUDE.md, and similar Markdown-based instructions with formatting preserved instead of raw text.
Review structured Markdown content
Check documents that rely on frontmatter, diagrams, or math and see those elements rendered inline inside Quick Look.
Switch between rendered and source views
Compare the rendered version and the original source when you need to verify formatting or copy the file as HTML.
Pros and Cons
Pros
- Keeps Markdown readable in Finder without opening an editor.
- Shows YAML frontmatter as a collapsible metadata table.
- Provides a rendered/source toggle and Copy as HTML action.
- Supports dark mode and follows the macOS appearance setting.
- Covers a wide range of Markdown features, including GFM, math, Mermaid, and syntax highlighting.
Cons
- Requires macOS 26 (Tahoe) or later.
- The source page does not provide a detailed pricing or licensing breakdown beyond describing the product as free and open source.
- Some capability details are only shown on the home page, so long-term documentation and support scope are not fully clear from the available sources.
FAQ
How do I enable showmd in Finder Quick Look?
Download showmd, open it once, then enable it in System Settings → Privacy & Security → Extensions → Quick Look. On first launch, macOS may ask to access data from other apps so the app and extension can share settings.
What happens to YAML frontmatter?
showmd parses the YAML frontmatter block and renders it as a collapsible metadata table, collapsed by default. The source shows support for plain values, quoted strings, arrays, and multi-line folded blocks.
Can I switch between rendered Markdown and source?
Yes. Every preview includes a Rendered / Source toggle, and the rendered view also offers a Copy as HTML option.
Does showmd support dark mode?
Yes. showmd follows the macOS appearance setting automatically, and its settings let you choose Light, Dark, or Auto.
Quick Facts
- Category
- Developer Tool
- Platform
- macOS
- Primary use
- Finder Quick Look previews for Markdown files
- Source domain
- showmd.yetanother.one
- Availability
- Free and open source
- System requirement
- macOS 26 (Tahoe) or later
showmd Alternatives
Codex Plugins
Codex Plugins bundle reusable skills, app integrations, and MCP servers into workflows you can install in the Codex app or use from Codex CLI.
Snapmark
Snapmark is a VS Code extension for annotating clipboard screenshots before pasting them into AI chats. Blur sensitive details, add numbered callouts, and auto-resize large images.
Open Computer Use
Open Computer Use is an open-source Computer Use service wrapped as MCP for macOS, Linux, and Windows. It helps AI agents and MCP clients run desktop automation workflows through client setup commands or manual MCP configuration.
Privacy-First Toolbox
Privacy-First Toolbox is a free browser-based collection of file and text conversion tools that processes data locally on your device. It is designed for users who want common utilities without uploading files or creating an account.
optimo
Optimo is a free, open-source CLI for optimizing and converting images and videos with format-specific commands built on ImageMagick and FFmpeg. It helps developers prepare web assets, batch process media, and automate compression from the shell or a Node.js script.
Converleon
Converleon is an offline Mac file converter for images, video, audio, documents, PDFs, and archives, with batch conversion and no uploads.