pyodide-py

What it is and what it does

Pyodide-py is a foundational package that provides the core interpreter functionality Pyodide needs to run Python in WebAssembly environments. It consists of two internal Python packages (_pyodide and pyodide) that are loaded at different stages of Pyodide's initialization: _pyodide loads first with only stdlib dependencies, while pyodide loads last and depends on a C extension (_pyodide_core). The package is primarily designed to be used as part of Pyodide's runtime, not as a standalone tool.

For native Python environments, the package can be installed for type checking and testing purposes. However, much of its functionality is unavailable outside Pyodide's WebAssembly context; the package provides type stubs and reimplementations for the APIs it exposes. This makes it useful for developers working on Pyodide itself or building Python applications intended to run in Pyodide, but not for general-purpose Python development.

Use it for:

• Type checking and IDE support when developing Python code intended to run in Pyodide's WebAssembly runtime.
• Testing Pyodide-dependent code in a native Python environment before deploying to WebAssembly.
• Contributing to Pyodide itself, where the package is an integral part of the runtime initialization.
• Building Python applications that target browser environments via Pyodide.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

Provides core interpreter functionality for Pyodide, enabling Python to run in WebAssembly environments. This package is essential for Pyodide's runtime and can be installed in native Python for type checking or testing.

Yes, but with strong conditions: install only if you are actively developing for Pyodide or building Python applications to run in WebAssembly via Pyodide. The Python 3.14 requirement is a hard blocker for most current environments. Outside Pyodide development workflows, this package has limited utility. No known security vulnerabilities, active maintenance, and low install friction are positive signals, but the use case is narrow and specialized.

Install

pyodide-py on PyPI

pip install pyodide-py

uv add pyodide-py

poetry add pyodide-py

Installing pyodide-py

Before you install

Low install friction with no runtime dependencies. Actively maintained with a recent release (10 days old) and strong repository signals (14786 stars, last commit 2026-08-14). However, requires Python 3.14 or later, which is a significant constraint for most current environments.

License in practice

Licensed under Mozilla Public License 2.0 (copyleft). Users must comply with MPL 2.0 terms, including source disclosure obligations if modifications are distributed. Suitable for open-source projects but requires careful review in proprietary contexts.

Quickstart

# Install
pip install pyodide-py==314.0.4

# Import in native Python (for type checking or testing)
import pyodide
import _pyodide

Requires Python 3.14 or later. Full functionality only available in Pyodide's WebAssembly runtime; native Python import provides type stubs and partial reimplementations.

Verify before relying

• Whether the package's type stubs and reimplementations cover enough of the Pyodide API surface for practical native Python testing workflows.
• Specific use cases where importing in native Python (rather than only in Pyodide runtime) provides value beyond type checking.

Package facts

Evidence: pyodide_py-314.0.4-py3-none-any.whl

Tags

More Software Development packages