Keel

A focused, native, read-only PDF reader for Mac

A focused, native, read-only PDF reader for Apple-silicon Macs, built with SwiftUI and PDFKit.

Keel never edits, annotates, decrypts to disk, or saves over the source PDF.

Features

• One window per document; open from Finder, File › Open, Open Recent, drag and drop, or the welcome window
• Continuous, single-page, and two-page layouts (with an optional separate cover), zoom, fit to width, page entry
• Native full screen and an optional Dark Pages mode for night reading
• Sidebar with page thumbnails, table of contents, and search results
• Password-protected PDFs, with optional Keychain storage per document
• Print through the standard print panel, and share the original PDF with AirDrop, Mail, Messages, and other services
• Reading position, zoom, layout, and sidebar state restored per document

Requirements

• Apple-silicon Mac running macOS 26 or later
• Xcode 26 or later (Command Line Tools alone cannot build the app)

Build and run

Open Keel.xcodeproj, select the Keel scheme and My Mac, then Product › Run.

From the command line:

xcodebuild -project Keel.xcodeproj -scheme Keel \
  -destination 'platform=macOS,arch=arm64' build   # or: test

If xcode-select -p points at Command Line Tools, run sudo xcode-select -s /Applications/Xcode.app or prefix commands with DEVELOPER_DIR=/Applications/Xcode.app/Contents/Developer.

The Swift package covers only KeelCore, for quick pure-logic builds and tests:

swift build
swift test

Project layout

Sources/Keel/         macOS app: AppKit/SwiftUI UI, PDFKit, Keychain
Sources/KeelCore/     Pure logic with no UI dependencies: identity, reader state, search excerpts, text-layer sampling
Tests/KeelCoreTests/  Unit tests for KeelCore
Keel/                 Info.plist and sandbox entitlements

See AGENTS.md for architecture notes and conventions.