Building a Local PlantUML Extension for Hugo: No External Dependencies Required

When writing technical documentation, diagrams are essential for explaining complex architectures and workflows. PlantUML is a fantastic tool for creating diagrams from simple text descriptions, but most Hugo implementations rely on external web services or require manual diagram generation. Today, I’ll show you how to build a complete Hugo extension that processes PlantUML diagrams locally using Hugo shortcodes—no external dependencies, no source file modifications, just seamless integration. Why Build a Local PlantUML Extension? Most Hugo PlantUML solutions have significant limitations: