Graphviz
Graphviz is an open-source graph visualization software that uses the DOT language to describe graphs and automatically generates layouts for diagrams, flowcharts, network diagrams, and other visual representations of structured data. It provides a suite of command-line tools and libraries for rendering graphs into various output formats like PNG, SVG, and PDF, making it widely used for automated diagram generation in software documentation, data analysis, and system design.
Developers should learn Graphviz when they need to programmatically create diagrams for visualizing complex relationships, such as dependency graphs in codebases, network topologies, or state machines, as it eliminates manual drawing and ensures consistency. It is particularly useful in DevOps for infrastructure mapping, in software engineering for generating UML diagrams from code, and in data science for visualizing graph-based data structures, offering a lightweight, scriptable alternative to GUI-based diagramming tools.