Quickly Create UML Diagrams in IntelliJ IDEA with PlantUML

What is PlantUML

PlantUML is an open‑source tool that lets you describe UML diagrams with a simple text language. It uses the Graphviz rendering engine to generate PNG, SVG or other image formats.

Key Advantages

Pure text editing – no drag‑and‑drop, automatic layout and clean syntax.

Platform‑independent – works as long as the PlantUML JAR is available.

Integrates with many editors and IDEs such as IntelliJ IDEA, Eclipse, Notepad++.

Installing the PlantUML Plugin in IntelliJ IDEA

Open File → Settings → Plugins, search for “PlantUML”, locate “PlantUML integration” and click Install.

Installing Graphviz

Download the Windows installer from the official site:

https://graphviz.gitlab.io/_pages/Download/windows/graphviz-2.38.msi

After installation, add the following environment variables:

GRAPHVIZ_HOME = D:\WorkWare\Graphviz2.38
Path = %GRAPHVIZ_HOME%\bin
GRAPHVIZ_DOT = %GRAPHVIZ_HOME%\bin\dot.exe

Verify the setup by running dot -version in a command prompt; the version information should be displayed.

Configure PlantUML in IDEA

Go to File → Settings → Other Settings → PlantUML and ensure the path to the Graphviz dot executable is correct.

Creating a Simple Sequence Diagram

Create a new .uml file and write the following text:

@startuml
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response

Alice -> Bob: Another authentication Request
Alice <-- Bob: another authentication Response
@enduml

The right‑hand pane shows the rendered diagram instantly.

Generating a UML Class Diagram

You can also write class definitions in the same file; PlantUML will produce a class diagram.

Alternative Without Graphviz

If you prefer not to install Graphviz, you can use the Chrome extension “PlantUML Viewer”, which renders diagrams directly in the browser from the text source.