Clearly

Clearly opens ordinary .md files and edits them in a native text view with syntax highlighting, formatting shortcuts, a heading outline and find and replace with regular expressions. A toggle switches to a rendered preview with GitHub-flavoured tables and task lists, KaTeX math, Mermaid diagrams, callouts and highlighted code blocks, and documents can be exported or printed as PDF. A Quick Look extension previews Markdown in Finder, and a menu bar scratchpad opens floating notes from a global shortcut.

It suits people who keep notes, docs or drafts as plain Markdown files and want a fast single-document editor rather than a notes library. An iPhone version shares the same renderer.

The Mac app needs macOS 15 or later and is a universal build, signed and notarized, with Sparkle updates. The same app is free on the Mac App Store. The project says it collects no telemetry. Its license is source-available rather than open source: building a competing commercial product from the code is not allowed until a release turns MIT two years after publication.