Python SDK — Development

Contributor guide for building and testing the runanywhere Python package from source.

Prerequisites

• Python 3.9+
• A C++20 toolchain and CMake (for the native _core extension)
• Built or co-located runanywhere-commons sources (scikit-build-core drives CMake)

Editable install

The SDK builds via scikit-build-core, which compiles the native _core extension from runanywhere-commons.

cd sdk/runanywhere-python
pip install -e ".[test]"

Tests

pytest tests

The suite includes pure-Python tests that fake the native core, so you can run many tests without a full native build.

Architecture notes

• The compiled native runtime loads lazily on the first initialize(), so importing runanywhere is side-effect-free.
• Multiple RunAnywhere clients share one reference-counted underlying runtime.
• See AGENTS.md in this directory for the full architecture, build details, and lazy-load design.