PreviewMD

PreviewMD shows Markdown files as formatted pages when you press Space on them in Finder, with headings, tables, checklists, code and images. It also has a small native reader for browsing files and folders. It suits people who keep notes, READMEs or documentation as Markdown and want to read them without opening an editor. According to the README, documents are rendered locally and the app has no telemetry, accounts or automatic update checks.

Requires macOS 13 or later and runs on Apple silicon and Intel. The README describes the release DMG as notarized. Quick Look needs the extension switched on: open the app once, then enable PreviewMD under Quick Look in System Settings (Login Items & Extensions on macOS 15, Privacy & Security on macOS 13 and 14). Builds from source are ad-hoc signed.