Show HN: Scriptum, a native Mac Markdown editor that live reloads

Scriptum, a native Mac Markdown editor built with SwiftUI, launches with live rendering of math, Mermaid diagrams, and code, plus full-screen slideshows and automatic preview refresh when another app rewrites the file. The app exports to PDF and HTML with styling intact, supports iCloud Drive syncing, and requires macOS 14.0 or later. Developer notes that an iPhone reader version is available and an iPad editing canvas is in development.

The Markdown editor macOS deserves. Math and Mermaid diagrams render as you type. Any document becomes a full-screen slideshow. Article View turns a working draft into something worth reading, and the preview refreshes itself the moment another app rewrites the file. Native SwiftUI throughout, exporting to PDF and HTML with the styling intact. Math, diagrams, alerts, and code, all rendered live as you type. Features From quick notes to technical papers with math, diagrams, and live code. Scriptum adapts to how you work. Write in the rendered document itself. Headings, bold, links, tables, math, and code blocks all take their real appearance as you type, and the Markdown behind them is still exactly what gets saved. Reveal the raw syntax any time by putting your cursor in it. The preview refreshes the moment another app changes the file, your editor, a build script, or an AI tool writing Markdown. Keep Scriptum beside your terminal and watch documents take shape. Turn any document into a full-screen slideshow. Split slides with < -- slide -- markers or H1/H2 headings. Navigate with arrow keys or clicks. Inline and block math rendered with KaTeX. Write equations with $...$ and $$...$$ , see them typeset instantly. Flowcharts, sequence diagrams, ER diagrams, Gantt charts, pie charts, mindmaps, and git graphs, rendered live in the preview. Write on the Mac, read anywhere. Documents in iCloud Drive open on your iPhone rendered exactly the same way, math, diagrams, and tables included. See it below iphone . Split, reader, and editor modes with synchronized scrolling · Standard and Article View reading typography · document outline, one click to any heading · find in the rendered preview with Cmd + F Light, dark, or follow the system · 13 typefaces, each file remembers its own · centered or full-width layout · text size from 10 to 32pt GitHub alerts · task lists with clickable checkboxes · footnotes · definition lists · highlights, superscript, subscript · syntax-highlighted code with a copy button Open any folder as a workspace with search and sort · auto-save as you type · plain .md on disk, never locked in Styled PDF and self-contained HTML · print · AirDrop, Mail, and Messages Scriptum is a native SwiftUI app, not a web wrapper. It respects your system settings and feels right at home on your Mac. Keep your documents in iCloud Drive and they follow you. Write a note on your Mac and it is right there on your iPhone. Every document is a plain .md text file, openable in any app, never locked in. Scriptum can even be your default Markdown editor. Your work saves automatically as you type. And if another app changes a file while it is open, Scriptum offers to reload or keep your edits. On the Horizon Scriptum for iPhone renders the same documents the same way, math and diagrams included, from the iCloud Drive folder you already keep them in. Editing stays on the desktop for now; the phone is built for reading what you wrote. In DevelopmentA full editing canvas built for iPad, with split view, hardware keyboard shortcuts, and Apple Pencil in mind. Write technical notes and present slideshows from anywhere. Requirements: macOS 14.0 Sonoma or later. Built with Swift and SwiftUI.