.pyz format

What is a .pyz?

A .pyz file is a standard Python ZIP application - a ZIP archive that Python (and bunpy) can execute directly. It contains:

myapp.pyz
├── __main__.py      # entry point
├── myapp/           # your package
│   ├── __init__.py
│   └── server.py
└── requests/        # vendored dependencies
    └── ...

The archive has a #!/usr/bin/env bunpy shebang prepended so it is directly executable on POSIX systems.

Building a .pyz

bunpy build app.py
# → app.pyz  (24 KB)

Specify the output name:

bunpy build -o dist/myapp.pyz src/myapp/__main__.py

Running a .pyz

bunpy app.pyz
# or, after chmod +x:
./app.pyz

What gets bundled

bunpy traces import statements statically and includes:

• Your entry point and all reachable local modules
• Any wheels installed in .bunpy/site-packages/ that are imported

Standard library modules are not bundled - they are provided by the goipy VM at run time.

Size

A minimal script bundles to a few KB. A script importing requests typically bundles to ~200 KB.

.pyz vs –compile