Browsedown

A Rails engine that serves a directory of markdown files as a browsable documentation site.

Point it at a folder, mount it in your routes, and your .md files become readable in the browser with a sidebar, dark/light mode, and prose-optimized typography.

Installation

Add to your Gemfile:

gem "browsedown"

Usage

Mount it in config/routes.rb:

mount Browsedown["docs"] => "/documentation"

This serves all .md files under Rails.root/docs at /documentation.

The path argument is relative to Rails.root:

Browsedown["content/guides"]  # => Rails.root/content/guides

How it works

• Scans the directory tree for *.md files
• Renders markdown to HTML using Redcarpet (fenced code blocks, tables, autolinks, strikethrough)
• Displays a sidebar with links to every page
• Shows README.md as the landing page if one exists
• Blocks path traversal — requests outside the configured root return 404

Requirements

• Ruby >= 3.0
• Rails >= 6.0

License

MIT