About this project

I am a huge fan of PlantUML. I never really warmed to the publicly available online editors, though. So I built my own: PlantUML Power Editor.

Why PlantUML?

Writing diagrams as text is hard to beat: they can be versioned, compared in code reviews and changed quickly, and they still look good. PlantUML covers almost everything, from sequence and class diagrams to mind maps and Gantt charts.

Why another editor?

The available editors always lacked something for me: an instant preview that does not keep disappearing while typing, error messages right at the affected line, useful autocompletion and the ability to simply click elements and style them. Plus a modern, clean design that also works on a phone. So I started this project, primarily for myself. If you find it useful, you are welcome to use it too.

Not an official PlantUML project

I am not part of the PlantUML team and I am not affiliated with its developers. I am simply an overly enthusiastic user. PlantUML itself is developed as an open source project by Arnaud Roques and many contributors. Everything about the language can be found on the official PlantUML website.

Rendered right in your browser

The editor uses the official JavaScript implementation of PlantUML: PlantUML's Java code is compiled to JavaScript with TeaVM, and Graphviz handles the layout as WebAssembly. Your diagrams are therefore rendered entirely locally in your browser. There is no remote server that receives your source code or generates images, and your diagrams never leave your device. Details are in the privacy policy.

Technologies used

• @plantuml/core: PlantUML as JavaScript (compiled with TeaVM), including Graphviz as WebAssembly
• Angular with signals and Angular Material (Material 3)
• CodeMirror 6 for the editor, syntax highlighting and autocompletion
• The fonts Inter and JetBrains Mono plus Material Symbols, all served from this server
• The browser's local storage for saved diagrams and settings
• Delivered as a static website by nginx in a Docker container

Open source

The source code is on GitHub. Feel free to report bugs and ideas there as an issue.

Manuel Seiche, mseiche.de