Sirène — Native Markdown & Mermaid for macOS

Everything in its right place

A focused, native reading and writing experience, with none of the Electron weight.

📊

Live Mermaid diagrams

Flowcharts, sequence diagrams, Gantt charts and more render the moment you open or edit a file.

✍️

Read & edit

Toggle between crisp GitHub-style preview and raw Markdown source with a single keystroke.

🔄

Live reload

Change a file in any editor and Sirène updates instantly. Atomic saves are handled cleanly.

🗂️

Tabs & sessions

Open many documents in native macOS tabs and pick up right where you left off after a relaunch.

🔎

Find your way

A Table of Contents sidebar and in-document search make long documents easy to navigate.

🖨️

Print & export

Print or save to PDF with proper formatting and rendered diagrams fully intact.

See it in action

Your Markdown, rendered faithfully, diagrams and all.

Sirène rendering a Mermaid flowchart with a table-of-contents sidebar — Live preview with a rendered Mermaid flowchart and Table of Contents.

Sirène rendering a Mermaid sequence diagram for the AI Enhance workflow — Sequence diagrams render just as cleanly.

AI-assisted writing, on your terms

Leave a marker like [[:TODO write an introduction]] and run Enhance to have Claude write it, in your document's own tone and structure.

This feature is entirely optional and uses your own Anthropic API key, stored securely in your macOS Keychain. Document content is sent to Anthropic only when you choose to run Enhance.