SSMV

SSMV opens local Markdown files and public Markdown URLs in a native window. A collapsible sidebar keeps several documents together, you can jump between headings, and any document can be exported to PDF. Mermaid diagrams render locally, without a background server. It is read-only by design, so it is for reading Markdown rather than editing it. The Windows edition is a preview and does not yet match every macOS feature.

The macOS app needs macOS 13 or later and runs on Apple silicon and Intel as a universal build; it can also be installed with Homebrew. Version 0.6.0 is ad-hoc signed and not notarized by Apple. The Homebrew cask removes the quarantine flag, but a manually downloaded copy may be blocked on first launch and then needs approval under System Settings > Privacy & Security. The README says the app has no analytics; opening a remote document sends a request to that document's server, including its query parameters. The Windows installers are unsigned.