Hey everyone,
I’m AlexTDev and I develop Mermaid Visualizer, an open-source IntelliJ plugin that renders Mermaid diagrams directly in your IDE.
It started from a simple problem: the official JetBrains Mermaid plugin doesn’t support recent diagram types (architecture, kanban, treemap…). Rather than waiting for an update, I decided to build an alternative. It was also a way to dive into the IntelliJ Platform ecosystem from scratch — JCEF, JFlex, the Marketplace — a real learning ground.
Today the plugin ships with Mermaid.js v11.12, supports all 22 diagram types, works entirely offline and offers:
— Rendering of mermaid blocks in the Markdown preview
— A dedicated editor for .mmd/.mermaid files with side-by-side live preview and synchronized scrolling
— Full syntax highlighting powered by a JFlex lexer written from scratch (keywords, arrows, directives, strings… across all 22 diagram types)
— SVG/PNG export and diagram zoom
— Automatic dark mode detection
— A Color Settings page to customize colors in the IDE
Next up: autocompletion, among other things. I don’t know how far I’ll go but every step teaches me something new.
If Mermaid is part of your daily workflow, the plugin is available for free on the JetBrains Marketplace: https://plugins.jetbrains.com/plugin/30432-mermaid-visualizer
The project is fully open-source — you can check out the code, open issues or contribute on GitHub: https://github.com/Alex9583/MermaidVisualizer
A coffee helps me keep developing and maintaining this project in my spare time. And if you have feedback or feature ideas, that matters just as much — feel free to share here or on GitHub.
Thanks for being here.