Try the online pymermaider playground! powered by WebAssembly 🎉

pymermaider is a tool written in Rust designed to generate mermaid.js class diagrams from Python code. By analyzing Python code, pymermaider automatically generates mermaid.js-compatible diagrams that represent the class structures, including classes, methods, attributes, and their relationships. This tool aims to simplify the documentation process for Python projects, making it easier to visualize class hierarchies and relationships.

• Automatic Class Diagram Generation: Generate detailed class diagrams from Python codebases with minimal configuration.
• Mermaid.js Compatibility: Outputs diagrams in mermaid.js markdown syntax, ready to be embedded in your markdown documents or rendered using mermaid.js tools. GitHub supports this natively as you'll see below!

pymermaider is available on PYPI:

# With pip.
pip install pymermaider

# With pipx.
pipx install pymermaider

pymermaider [OPTIONS] <PATH>

• <PATH> Path to a file or directory. Use '-' to read Python source from stdin.

• -m, --multiple-files Process each file individually, outputting a mermaid file for each file. Only used when path is a directory.

• -o, --output-dir <OUTPUT> Output directory for mermaid files. [default: ./output]

• --output-format <OUTPUT_FORMAT> Output file format. [default: md] [possible values: md, mmd]

  • mmd may become the default in the future, depending on user feedback

• --output <OUTPUT> Output file path. Use '-' to write to stdout. Not compatible with --multiple-files.

• --direction <DIRECTION> Class diagram direction. [default: TB] [possible values: TB, BT, LR, RL]

• --no-title Omit the title from the diagram output.

• -h, --help Display help information for the command.

• -V, --version Show the current version of pymermaider.

• --exclude <FILE_PATTERN>: Excludes specific files and/or directories from being analyzed.
• --extend-exclude <FILE_PATTERN>: Similar to --exclude, but adds additional files and directories to exclude on top of those already specified.

pymermaider /path/to/dir --extend-exclude "**/tests/*,**/docs/*"

This command will exclude any folders within the subdirectories of /path/to/dir that are named tests or docs.

pymermaider /path/to/dir --output-dir ./output --output-format mmd

# py file -> stdout
pymermaider my_file.py --output -

# stdin -> stdout
cat my_file.py | pymermaider - --output -

# py file -> file (raw Mermaid)
pymermaider my_file.py --output-format mmd --output diagram.mmd

# directory -> stdout (single combined diagram)
pymermaider ./my_project --output - > diagram.md

• Some codebases are so massive that processing the directory into one file will result in mermaid code that's too large to render. By default, it's 50,000 characters. This is a good reason for the -m flag. You can break class diagrams apart more easily into multiple renderings.

Given a Python file example.py with the following content:

class Animal:
    def __init__(self, name: str) -> None:
        self.name = name

class Dog(Animal):
    def bark(self) -> str:
        return "Woof!"

Running pymermaider on this file will provide:

classDiagram
    class Animal {
        - __init__(self, name) None
    }

    class Dog {
        + bark(self) str
    }

    Dog --|> Animal

• Import/type resolution powered by ty
• More language support, maybe?? 😳🤔

• methods with property-setter decorators can be confusing in the output

Contributions are more than welcome, just make a PR and we'll go from there!

This project is licensed under the MIT license. Please see the LICENSE file for more details.