SwiftPlantUML

SwiftPlantUML provides an Xcode source‑editor extension and a macOS application that generate PlantUML class diagrams directly from Swift code. Within Xcode users can create a diagram for an entire file or for a selected snippet, and the same functionality is available from Finder to generate diagrams for chosen Swift files. The generated diagrams are displayed in the companion app, where visual appearance can be adjusted through a preferences panel.

The tool relies on the SwiftPlantUML Swift package and its SourceKitten dependency, running the heavy parsing work in an XPC service to keep the extension sandboxed. For larger projects the command‑line version of SwiftPlantUML can be used to produce comprehensive diagrams across multiple folders. Installation is supported via Homebrew or by downloading a release package and placing it in the Applications folder.

Targeted at Swift developers who need quick visual insight into class relationships, the extension integrates into the standard macOS system preferences workflow for enabling Xcode source‑editor and Finder extensions. It is open‑source, free to use, and marked as stable.