Best Mermaid Viewers for Mac

Quick Comparison

MDViewer

Best for: viewing Mermaid diagrams in Markdown files on Mac.

MDViewer is a native macOS app that renders Mermaid diagrams as interactive SVGs. You can zoom, pan, and open diagrams in a full-screen lightbox. It supports all Mermaid diagram types and also opens standalone .mmd and .mermaid files directly from Finder.

The QuickLook extension is particularly useful — press Space on any .md or .mmd file in Finder and see the rendered diagram without opening the app.

MDViewer is free, launches instantly (native SwiftUI), and also provides Git history, inline editing, tabs, and a smart table of contents for the Markdown around the diagrams.

VS Code with Mermaid Extensions

Best for: editing Mermaid diagrams while writing code.

VS Code supports Mermaid through extensions like Markdown Preview Mermaid Support (bierner.markdown-mermaid) and Mermaid Editor. The Markdown preview pane renders Mermaid blocks alongside your text.

The advantage is that you edit and preview in the same window. The disadvantage is that VS Code’s Markdown preview is a secondary feature — it uses more resources than a dedicated viewer, and the Mermaid rendering is not interactive (no zoom or pan).

If VS Code is already your editor, adding a Mermaid extension is the easiest path. For reading documentation, a dedicated viewer like MDViewer is faster and lighter.

Mermaid Live Editor

Best for: quick prototyping and sharing diagrams.

The official Mermaid Live Editor (mermaid.live) is a browser-based tool where you write Mermaid code on the left and see the rendered diagram on the right. It’s the fastest way to experiment with syntax and share diagrams via URL.

Limitations: it requires an internet connection, doesn’t open local files, and doesn’t integrate with your Markdown workflow. It’s a prototyping tool, not a viewer.

Mermaid Chart

Best for: teams that need collaboration and enterprise features.

Mermaid Chart is a commercial product from the Mermaid.js team. It provides a visual editor, team collaboration, version history, and integrations with Jira and Confluence. The free tier is limited; Pro starts at $10/month.

It’s overkill for individual developers who just need to view diagrams in their Markdown files.

GitHub and GitLab

Best for: viewing diagrams where your code already lives.

Both platforms render Mermaid code blocks natively in README files, issues, pull requests, and wikis. This means your team can see diagrams without installing anything.

The rendering is static — no zoom, no pan, no interaction. For large or complex diagrams, you need a local tool.

Obsidian

Best for: personal knowledge bases with occasional diagrams.

Obsidian renders Mermaid code blocks inside notes. If you already use Obsidian for your notes, Mermaid support comes built-in. The rendering is basic — no zoom or interaction — and Obsidian doesn’t open arbitrary .md files from Finder without importing them into a vault.

Who Should Use What

• Reading Mermaid in project docs: MDViewer — opens files from Finder, interactive diagrams, QuickLook preview
• Editing Mermaid while coding: VS Code with Mermaid extension
• Quick prototyping: Mermaid Live Editor
• Team collaboration: Mermaid Chart
• Diagrams in your notes: Obsidian
• Sharing with your team: GitHub / GitLab (no setup needed)

Try MDViewer

MDViewer renders all Mermaid diagram types as interactive SVGs — with zoom, pan, and full-screen lightbox. Free for early adopters.

Requires macOS 13.0 or later. Intel and Apple Silicon.