Folio

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Folio is a local-first, native macOS Markdown reader and lightweight editor. It is built entirely with SwiftUI and renders Markdown without a WebView: swift-markdown parses GitHub Flavored Markdown and the renderer emits native SwiftUI views and AttributedStrings. The focus is comfortable long-form reading, with several visual themes for different writing styles and lighting conditions.

Folio is the current app and is macOS-only. The original cross-platform implementation (a React + Tauri app named PreviewerMD) still lives in this repository under Previewer.md/.

Claude Dark theme	Find in document

• Open individual Markdown files or browse a folder of Markdown documents.
• Native sidebar file tree with pinned and recent workspace folders.
• Render GitHub Flavored Markdown — headings, lists, task lists, tables, blockquotes, strikethrough, links, and fenced code blocks.
• Native syntax highlighting for code blocks (~30 languages, no highlight.js).
• Switch between preview and split editor/preview modes; edits save to disk.
• Find within the current document (⌘F) with highlight and wraparound.
• Print or export to PDF through the native print pipeline (⌘P).
• Multiple workspace windows, each with its own document and theme.
• Open .md/.markdown files directly from Finder (file associations).
• Choose from several reading themes — Vercel (default), Claude, Claude Dark, Lovable, Spotify, Dark, and High Contrast. Warm editorial themes set their headings in a serif face.
• Window position and size are restored across launches.

• macOS 15 or newer
• Swift 6 toolchain (Xcode 16 or the matching command-line tools)

cd Folio
swift build          # compile
swift test           # run the test suite
swift run            # launch with the welcome document

To produce a distributable app bundle (icon + file associations, ad-hoc signed):

cd Folio
./scripts/bundle.sh        # → dist/Folio.app
./scripts/bundle.sh --dmg  # → also dist/Folio.dmg

Install with cp -R dist/Folio.app /Applications/.

Dev conveniences (plain executable, no bundle needed):

FOLIO_OPEN=~/notes swift run            # open a folder/file at launch
FOLIO_THEME=claude swift run            # seed the reading theme
FOLIO_EXPORT_PDF=/tmp/doc.pdf swift run # headless print-render to PDF

Inside Folio/, the Swift modules map closely to the behavior of the Tauri app's TypeScript modules (each has tests); see Folio/README.md for the file-by-file map and milestone history.

The cross-platform React + TypeScript + Vite + Tauri app remains available for macOS, Windows, and Linux.

cd Previewer.md
npm install
npm run tauri -- dev     # develop
npm run tauri -- build   # package

Renderer-side code lives in Previewer.md/src/; native commands and Tauri setup live in Previewer.md/src-tauri/.

• Folio is local-first and only works with files the user selects.
• Do not commit signing certificates, provisioning profiles, generated archives, or platform-specific build output.

Issues and pull requests are welcome. For code changes, include focused tests when practical and run swift test (and, for the Tauri app, its own checks) before opening a pull request.

This project is licensed under the MIT License. See LICENSE.