Show HN: A fast, offline Markdown viewer for macOS built in Swift

Hi HN! I made Tim’s Markdown Reader because I wanted a free, open-source app just for reading Markdown. I spend a lot of time working with AI coding agents, and sometimes I just want to open the files they produce and read them without opening an editor.

It’s written in Swift and works entirely offline, including Mermaid diagrams. It has no accounts, telemetry or network requests.

You can click links to other Markdown files and open them in the same window, with back and forward buttons. It also has search, automatic reload when a file changes, light and dark modes, adjustable fonts and text size, and centred or full-width layouts.

It started as something I needed myself, but I’ve since spent quite a bit of time refining it for public release. I wanted to keep it fast and minimal while making it feel like a proper Mac app, with attention to small details.

It’s MIT licensed, and the app is Developer ID-signed and notarized by Apple. Requires Apple silicon and macOS 14 or later (tested on macOS 26 and 27).

This is my first public open-source release. Would be good to hear what you guys think!