vizzpy 0.5.0

Interactive Python call tree visualizer — upload a project, explore its call graph in the browser

VizzPy

Interactive Python call tree visualizer. Upload a Python project and explore its function call graph in the browser. Here are some usecases:

• Bake the headless mode in your CI pipeline for adding auto-generated call tree in your repo (auto-documentation helping in understaanding the functionality and its implementation)
• Use in interactive mode to explore and understand the implementation of a particular functionality. This can also be helpful ahead of code reviews.

Features

• Interactive web UI — zoom, pan, drag nodes, collapse subtrees
• Cross-module resolution — follows imports across files to draw edges between modules
• Dark mode — toggle with one click
• Headless mode — render a static SVG or Mermaid flowchart from the command line (SVG requires Graphviz)
• Zip upload — drag-and-drop a .zip or .tar.gz (or add a local folder in headless mode)

Installation

Install only what you need:

Goal	Command
Mermaid headless (CI-friendly, zero extra deps)	pip install vizzpy
SVG headless	pip install 'vizzpy[svg]'
Interactive web UI	pip install 'vizzpy[serve]'
Everything	pip install 'vizzpy[all]'

SVG rendering additionally requires the Graphviz system package:

# macOS
brew install graphviz

# Debian/Ubuntu
apt install graphviz

Usage

Web UI (recommended)

vizzpy --serve
# open http://127.0.0.1:8000

Upload a .zip of your Python project or select a local folder, then click Analyze.

• Scroll / pinch to zoom
• Drag background to pan
• Drag nodes to rearrange
• Double-click a node to collapse/expand its call subtree
• Hover a node to see its docstring

Headless rendering

# SVG (default) — requires Graphviz
vizzpy --headless ./myproject
vizzpy --headless ./myproject --output call_tree.svg

# Mermaid markdown — no extra dependencies
vizzpy --headless ./myproject --format mermaid
vizzpy --headless ./myproject --format mermaid --output call_tree.md

Options

vizzpy --serve   [--host HOST] [--port PORT]
vizzpy --headless PROJECT_PATH [--format svg|mermaid] [--output OUTPUT]

How it works

VizPy uses Python's ast module to do a two-pass analysis of your source files:

1. Scope pass — collects every top-level function and class method with its qualified name (module.ClassName.method)
2. Edge pass — walks each file again, resolves self.method(), cls.method(), imported names, and direct calls to project-internal functions

Results are rendered in the browser with dagre-d3 (vendored, works offline). Calls to explicitly imported library functions (e.g. pandas.read_csv) are shown as external leaf nodes — their internals are not traced.

Development

git clone https://github.com/atulsaurav/vizzpy
cd vizzpy
pip install -e ".[dev]"

# run tests
pytest

# run with coverage
pytest --cov=vizzpy --cov-report=term-missing

License

MIT