Installation

The Holoscan Python API requires Linux and Python 3.12 or newer. Install a packaged SDK for application use, or import the package directly from an SDK build tree when developing the SDK itself.

You will learn

Where to find the release-specific Python package
How to build and import the package from an SDK checkout
How to verify the installed API and typing marker

Install a packaged SDK

Use the distribution name and CUDA variant published with the Holoscan 5.x release. The complete platform, driver, package, and CUDA prerequisites are maintained on SDK installation. Do not reuse a Holoscan 4.x wheel name for a 5.x environment. Use an isolated virtual environment when the application controls its Python dependency set.

Import from an SDK build tree

Python bindings are enabled by default. From a source checkout, select an explicit build directory and expose its package directory:

./run build --build-python true --buildpath build-holoscan
PYTHONPATH="$PWD/build-holoscan/python/lib" python3 -c \
  'import holoscan as hs; print(hs.__version__)'

The PYTHONPATH adjustment is for build-tree development only. An installed package or wheel supplies its own import path and runtime-library layout.

Verify operator discovery and typing

import holoscan as hs
print(hs.__version__)
print(f"registered operators: {len(hs.registry.operators())}")
print(hs.RealtimeClock)

The distribution includes .pyi stubs and a py.typed marker, so type checkers and editors can use the public facade signatures and generated operator and reusable-graph proxy definitions without a separate stub package.

A third-party operator provider becomes visible only after its Python module or extension is imported. If a registry lookup reports an unknown operator, import the package that ships that operator before composing the graph.

Recap

Use Python 3.12 or newer and follow the release’s package instructions for the installed CUDA major version.
SDK contributors can import directly from <build>/python/lib.
Stubs and py.typed ship with the package; operator providers register their types when imported.