Software architecture diagrams are critical for visualizing system design and facilitating communication among engineering teams, enabling better planning and identification of potential issues. The choice of diagramming tool depends on the specific needs and use cases, such as brainstorming new features or maintaining accurate and evolving documentation. There are four main categories of diagramming tools, each with distinct features and trade-offs: drag-and-drop whiteboards for quick, flexible sketching; modeling tools for maintainable and reusable architecture documentation; diagram-as-code tools for version-controlled diagrams integrated into the development lifecycle; and auto-documentation tools that offer real-time, accurate system visibility by automatically updating based on live data. As systems grow in complexity, the trend towards automated and real-time documentation is becoming more prevalent, ensuring that teams have access to up-to-date information.