Master PlantUML in IntelliJ: Install, Configure Graphviz, and Create Diagrams

What is PlantUML

PlantUML is an open‑source project that enables fast creation of UML diagrams using a simple textual language, and it renders the diagrams with the powerful Graphviz graphics library. The generated diagrams can be exported as PNG images or scalable SVG files.

Advantages of PlantUML

Fully text‑based editing without drag‑and‑drop controls, automatically adjusts element spacing, and produces clean, attractive diagrams.

Independent of any development platform; as long as the PlantUML JAR is available, diagrams can be generated.

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

Since Java developers often use IntelliJ IDEA as their primary IDE, this guide focuses on using PlantUML within IDEA.

Installing the PlantUML Plugin in IntelliJ IDEA

Navigate to File → Settings → Plugins, search for "PlantUML", locate the "PlantUML integration" plugin, and install it.

Installing Graphviz on Your Computer

Download the Graphviz installer from the official site (e.g., graphviz-2.38.msi ).

Configuring Environment Variables

Add a system variable named GRAPHVIZ_HOME with the installation path (e.g., D:\WorkWare\Graphviz2.38). Then edit the Path variable to include: %GRAPHVIZ_HOME%\bin Also add a variable GRAPHVIZ_DOT with the value:

%GRAPHVIZ_HOME%\bin\dot.exe

Configuring Graphviz in IntelliJ IDEA

Open File → Settings → Other Settings → PlantUML and set the path to the Graphviz dot executable.

Creating Diagrams with PlantUML

Create a new .uml file in IDEA and write PlantUML code. Example:

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

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

The diagram is rendered in real time on the right side of the editor.

You can also generate UML class diagrams directly from your Java code using IDEA's built‑in features.

Other Options

If you prefer not to install Graphviz locally, you can use the Chrome extension "PlantUML Viewer" to edit PlantUML text and view diagrams directly in the browser.