MarkViewer

MarkViewer is a native macOS application that opens and renders Markdown files instantly, supporting GitHub‑flavored syntax such as tables, checklists, and code highlighting. It provides a live WYSIWYG editing experience where formatting appears as you type, and it can automatically generate a table of contents from document headings. The program runs entirely offline, uses minimal system resources, and works on both Intel and Apple Silicon Macs.

The tool includes multi‑tab and multi‑window navigation, a built‑in file explorer with terminal access, and search highlighting that marks matches with visual cues. Users can browse files, run commands, and edit several documents simultaneously without leaving the app.

An optional AI Review Loop lets users highlight passages, add inline annotations, and send an editable prompt to external AI assistants such as Claude or ChatGPT with a single keystroke. This workflow keeps AI‑generated content local, offering an offline, private diff view and hand‑off mechanism while preserving the core Markdown editing functionality.