What is code visualization?

Code visualization is the process of creating graphical representations of source code to help understand and analyze it. It can be used for a variety of purposes, including:

  • Understanding code: Visualizing code can make it easier to understand how a program works, especially for large or complex programs. It can also help identify patterns and relationships within the code.
  • Debugging: Visualizing code can help identify errors or bugs in the code, and can help developers understand how code is structured and integrated, which can suggest possible solutions.
  • Communication: Code visualization can be used to communicate code to others, such as teammates or stakeholders. It can help explain how a program works and make it easier for others to understand. It can also be used during design review sessions, to consider a specific architecture or its alternatives.
  • Education: Code visualization can be used to teach programming concepts and techniques, especially to those who are new to programming. It can make it easier to understand complex code and provide a visual representation of how different parts of a program fit together.

This is part of a series of articles about code documentation

How code visualization tools work

Code visualization tools work by taking software code and related data, and using various algorithms and visualization techniques to represent it visually.

Here are some of the key features and capabilities of code visualization tools:

  • Visualization techniques: Code visualization tools use various visualization techniques, such as UML diagrams, flowcharts, and heat maps, to represent the code visually. These techniques can be customized and adjusted to meet the needs of different developers and applications.
  • Interactivity: Many code visualization tools allow developers to interact with the visualization, by zooming in or out, filtering data, or selecting specific code elements for further analysis.
  • Collaboration: Some code visualization tools support collaboration features, such as real-time editing, commenting, and sharing. This can help developers work together more effectively and share insights and feedback.
  • Parsing: Code visualization tools often include parsers that can extract relevant information from software code, such as function names, variable names, and relationships between different code elements. This is only optional though, as some visualization tools rely on code elements and links that the user specifies.
  • Integration: Code visualization tools can often be integrated with other software development tools, such as IDEs, version control systems, and testing frameworks. This can help developers streamline their workflow and improve their productivity.

Top 7 code visualization tools


Swimm is a knowledge management tool for code. It helps you manage all your engineering knowledge — by making it available in the IDE, integrated with code, and automatically updated.

Swimm allows you to create rich diagrams that include Smart Tokens. This way you can code-couple elements of your diagrams to constants or variables. You won’t need to worry about the impact of refactoring on your documentation and renaming those values referenced in your diagram. This means that diagrams in your documentation stay up to date with your code.


License: Commercial

Sourcegraph is a tool that provides code intelligence and code search capabilities for developers. It allows developers to search and browse source code across a variety of programming languages and repositories, and provides features such as code highlighting, definition tooltips, and cross-references to help developers understand and work with the code.

Sourcegraph also includes code visualization capabilities, such as code maps and UML diagrams, to help developers understand the structure and relationships in their code. It can be used in a variety of development environments, including popular integrated development environments (IDEs) like Visual Studio and Eclipse.

Key code visualization features include:

  • Code maps: These are interactive visualizations of the structure and relationships in code, including class hierarchies and call graphs.
  • UML diagrams: Sourcegraph allows developers to create and view UML diagrams, which can be useful for understanding the relationships between different parts of the code.
  • Definition tooltips: When working with code, developers can hover over a symbol to see a tooltip with its definition and documentation, making it easier to understand what the symbol represents.
  • Cross-references: Sourcegraph can show cross-references for symbols in the code, making it easier to see how a symbol is used and where it is defined.


License: Commercial

Embold is a tool that provides code analysis, visualization, and refactoring capabilities for developers. It allows developers to analyze and understand the structure and quality of their code, as well as identify potential issues and refactor the code to improve its maintainability and reliability.

Embold includes a number of code visualization features, such as code maps, UML diagrams, and dependency graphs, to help developers understand the structure and relationships in their code. 

  • Code maps: Embold can generate interactive maps of source code that show the relationships and dependencies between different parts of the codebase.
  • UML diagrams: Embold can generate UML (Unified Modeling Language) diagrams that show the structure and relationships within the code, including class diagrams, sequence diagrams, and other types of diagrams.
  • Graphs and charts: Embold can generate a variety of graphs and charts that show metrics and trends in the codebase, such as code complexity, testing coverage, and code duplication.
  • Code heatmaps: Embold can generate heatmaps that show which parts of the code are most heavily used or have the most potential issues, helping developers focus their attention on the most important areas of the code.


License: Commercial

Understand is a static analysis tool that allows developers to understand, analyze, and maintain complex code bases. Some of the main code visualization features of Understand include:

  • Interactive visualizations: Allows developers to create interactive visualizations of code structure and relationships, such as class diagrams, call graphs, and inheritance hierarchies. These visualizations can help developers understand the overall structure and relationships within the code, and they can be useful for tasks such as refactoring and optimizing performance.
  • Code metrics: Provides a range of metrics, such as cyclomatic complexity and maintainability index, which can help developers identify areas of the code that may be difficult to understand or maintain.
  • Code documentation: Generates detailed documentation for code, including information about classes, functions, variables, and more. This documentation can be useful for helping developers understand how the code works and for communicating with other developers.
  • Code searching and navigation: Provides the ability to search for specific code elements or navigate to related code elements. This can be useful for quickly finding and understanding specific parts of the code.


License: Commercial

CppDepend is a static code analysis tool specifically designed for C++ projects, and it provides a range of code visualization features:

  • Code Metrics: These metrics are presented in an easy-to-understand visual format, allowing developers to quickly see the overall health of their codebase.
  • Dependency Analysis: Allows developers to visualize the dependencies between different parts of their codebase. This can be helpful for understanding how the code works and for identifying potential issues or areas for improvement.
  • Code Map: Allows developers to visualize the structure of their codebase as a graph. This can be helpful for understanding the relationships between different parts of the code and for navigating through the code more easily.
  • Code Review: Allows developers to review code changes and provide feedback before they are committed to the codebase. This can be helpful for ensuring that code is of high quality and meets the standards of the project.


License: GPL-3.0 license

Gource is a tool that generates visualizations of codebases based on version control data. Some of the main features of Gource include:

  • File tree visualization: Generates a tree-like visualization of the codebase, with each file represented as a node in the tree. As the visualization plays, the tree grows and changes to reflect the addition and modification of files.
  • Customization: Allows users to customize the visualization in various ways, such as by specifying which types of files or events to include or exclude, and by adjusting the appearance of the visualization.
  • Color coding: Uses different colors to represent different types of files or events, such as new files (green), modified files (yellow), and deleted files (red).
  • File movement: Shows the movement of files within the codebase, such as when a file is moved from one directory to another.
  • Branching and merging: Shows the relationship between different branches and when they are merged together.


Source Insight is a code editor and source code analysis tool developed by Source Dynamics, Inc. It is designed to help developers navigate, analyze, and understand large codebases. Some of the main code visualization features of Source Insight include:

  • Symbol browsing: Allows developers to easily navigate through a codebase by displaying a list of symbols (e.g., variables, functions, classes) and their locations in the code.
  • Cross-reference analysis: Allows developers to see how different parts of the codebase are interconnected and how they depend on each other.
  • Interactive code maps: Can create interactive graphical maps of code relationships, which can be used to understand the structure and dependencies within a codebase.
  • Syntax highlighting: Provides syntax highlighting for a variety of programming languages, which makes it easier to read and understand code.
  • Debugging: Provides the ability to set breakpoints, step through code, and inspect variables.

Code visualization product comparison

Each code visualization tool has its own specific capabilities and limitations, and you should carefully evaluate the features and capabilities of each tool to determine which one is the best fit for your needs. However, we created the table below to provide a quick summary of their capabilities.

ToolAutomated Updating of DiagramsSyntax HighlightDebuggingIDE PluginsEnables manual diagram creation

Code documentation with Swimm

Swimm is a documentation platform built to deal with the main challenges of documentation for software engineering teams that want to create and manage internal documentation about their project.

Swimm’s core features include:

  • DaC (Documentation as code)—Swimm documents are written in Markdown form and saved within the codebase.
  • “Live” code—To make documents easier to write and richer, Swimm enables adding code snippets, diagrams, and tokens taken directly from the codebase.
  • Automatic sync—Using a dedicated application, Swimm integrates into CI to locate and automatically correct documents that become stale as relevant code changes. Developers are prompted if code changes are significant and demand their attention.
  • Enhanced discoverability—Swimm enables various ways to find documentation when needed. Its web application is used to structure documents using tags and Playlists and to search documents across repositories. Swimm also integrates with IDEs to highlight relevant docs next to code they relate to, enabling you to read them from the IDE without switching contexts.

Get started with Swimm today!