Graphviz — The Complete Guide: Free Diagrams and Graphs Generated Automatically From Text
Graphviz is an open-source collection of tools for drawing graphs. Instead of dragging shapes, you write a description in the DOT language — what connects to what — and Graphviz calculates the layout. When the diagram grows or changes, you simply run it again.
Graphviz
Graphviz Project
Draws graphs and network diagrams automatically from a text description.
Get it from the vendorWhat you get
- Automatic layout — dot for hierarchical diagrams, neato and fdp for networks, circo for circular ones.
- Full styling — shapes, colours, labels and clusters.
- Output — SVG, PNG and PDF at document quality.
- Automation — generating diagrams from Python or from data.
- Document integration — supported in Quarto, Markdown and documentation tools.
Engineering uses
Fault trees and decision trees, dependencies between components or tasks, controller state machines, network or piping topology at schematic level, and module structure in code.
Related tools
For hand-drawn diagrams — diagrams.net. For generating diagrams from data — Python. For reports that combine code and diagrams — Quarto.
diagrams.net (draw.io)
JGraph
A full diagram editor in the browser, with no account required.
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Python
Python Software Foundation
The language behind most modern engineering computation, and its full ecosystem.
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Quarto
Posit
Technical reports from code and data — Python, R or Julia into Word, PDF, HTML and slides.
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VSCodium
VSCodium project
The VS Code editor as a fully open build — Python, MATLAB, C, Markdown and more, without telemetry.
Get it from the vendorThe bottom line
When a diagram is derived from data or keeps changing, Graphviz saves hours of manual arranging.