# View Mermaid diagrams on your Mac without a browser

> Open .mmd and .mermaid files as diagrams with Quick Look: flowcharts, sequence, class and ER diagrams, Gantt charts and git graphs, with no browser.

A Mermaid file is only text until something draws it. Gander draws it right in Quick Look: select a `.mmd` file in Finder, press Space, and the diagram appears, with the source one click away. Mermaid blocks inside Markdown files are drawn too.

![roadmap.mmd as a Gantt chart: the Nimbus 3.0 roadmap with bars grouped by section.](https://ganderfinder.com/img/features/mmd-gantt-2x.webp)
![branches.mmd as a git graph with main and radar-v2 branches, merge commits and a v2.4.0 tag.](https://ganderfinder.com/img/features/mmd-git-2x.webp)
![architecture.mmd as a sequence diagram: a user, an iOS app, the Forecast API and Postgres exchanging requests.](https://ganderfinder.com/img/features/mmd-seq-2x.webp)

## How to do it

1. Install Gander from the Mac App Store and open it once.
2. Select a `.mmd` or `.mermaid` file in Finder and press Space.
3. Switch between **Diagram** and **Source**. The copy button copies a picture of the diagram, or the source text.

## The diagrams developers use

Gander draws these Mermaid diagram types:

- Flowcharts, sequence, class, state and entity-relationship diagrams
- Gantt charts, timelines and user journeys
- Git graphs, mindmaps, pie charts, quadrant charts and XY charts
- C4 and requirement diagrams

## Inside Markdown too

In a README, a fenced code block marked `mermaid` is drawn as a diagram inside the rendered page. When you [export the Markdown to PDF](https://ganderfinder.com/markdown-to-pdf-word), the diagram comes along as a vector drawing that stays sharp at any zoom.

## Drawn on your Mac

Diagrams are drawn natively, with no browser, no web service and no internet connection, so they work offline and nothing about your architecture leaves your Mac. In Finder’s icon and gallery views, Mermaid files get a thumbnail of their source.

## Questions

### Which files does Gander open as Mermaid?

`.mmd` and `.mermaid` files. In Markdown files, a fenced code block marked `mermaid` is drawn as a diagram.

### Do I need Node.js or the Mermaid CLI?

No. Gander draws the diagrams itself, and nothing else needs to be installed.

### Can I still read the Mermaid source?

Yes. The Source tab shows the file as written, with line numbers when you want them.

## More guides

- [Preview Markdown in Finder, rendered the way GitHub shows it](https://ganderfinder.com/markdown-quick-look)
- [Turn Markdown into a PDF or a Word document, right from Finder](https://ganderfinder.com/markdown-to-pdf-word)
- [Convert CSV to Excel on your Mac, straight from Finder](https://ganderfinder.com/csv-to-excel)
- [Read Jupyter notebooks on your Mac without starting Jupyter](https://ganderfinder.com/jupyter-notebook-viewer)
- [A fast JSON viewer in Finder, for JSONC and JSON Lines too](https://ganderfinder.com/json-viewer)
- [Look inside an SQLite database from Finder](https://ganderfinder.com/sqlite-viewer)
- [Read any SQL query neatly laid out, without changing the file](https://ganderfinder.com/sql-formatter)
- [Open log files at the newest line, with errors in red](https://ganderfinder.com/log-viewer)
- [Check a .env file without putting secrets on screen](https://ganderfinder.com/env-file-viewer)

Gander is free on the Mac App Store, with no in-app purchases, no subscription and no account, and nothing you preview leaves your Mac. https://apps.apple.com/app/id6817038818

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