---
id: wasmtime
version: "47.0.1"
license: Apache-2.0 WITH LLVM-exception
license_treatment: unclear
maintenance: active
---

# wasmtime — A WebAssembly runtime powered by Wasmtime

License: unclear · Maintenance: active · Downloads: 1.9M/mo

## What it is and what it does

Wasmtime is a Python binding to the Wasmtime WebAssembly runtime, a Bytecode Alliance project that lets you load, compile, and execute WebAssembly modules and components from within Python. It exposes a high-level API for creating stores, modules, instances, and calling exported functions, as well as importing Python functions into WebAssembly. The package ships as a precompiled wheel with no external runtime dependencies, making installation straightforward.

The runtime is actively maintained and follows Wasmtime's versioning scheme, releasing a new major version monthly. This means dependency specifications need regular updates to stay current. It supports modern Python versions (3.9 through 3.14) and PyPy on 64-bit Windows, macOS, and Linux systems. The package is suitable for embedding WebAssembly execution in Python applications, whether for sandboxed computation, plugin systems, or interoperability with WebAssembly-based libraries.

Use it for:

- Execute untrusted or sandboxed WebAssembly code from Python without spawning a separate process.
- Integrate WebAssembly modules compiled from other languages into Python applications.
- Build plugin systems where plugins are distributed as WebAssembly components.
- Call Python functions from within WebAssembly modules via the import interface.
- Prototype or test WebAssembly modules interactively in Python before deployment.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Embeds the Wasmtime WebAssembly runtime in Python, allowing you to compile, instantiate, and execute WebAssembly modules and components directly from Python code.

Yes. Wasmtime is a mature, actively maintained runtime with low install friction, no runtime dependencies, and broad platform support. The monthly major-version release cycle requires discipline in dependency management, but the package is well-documented and widely used. Install it if you need to execute WebAssembly from Python; verify the license terms for your use case first.

## Install

pip install wasmtime
uv add wasmtime
poetry add wasmtime

## Installing wasmtime

Before you install: Low friction: pure wheel distribution with no runtime dependencies. Actively maintained with releases every month; last commit 2026-07-20. Supports Python 3.9+ on Windows, macOS, and Linux for x86_64 and arm64.

License in practice: Licensed under Apache-2.0 WITH LLVM-exception. License treatment is marked unclear in the metadata, so verify the dual-license terms apply as expected for your use case before relying on it in proprietary or restricted contexts.

Quickstart:

pip install wasmtime

from wasmtime import Store, Module, Instance

store = Store()
module = Module(store.engine, "(module (func (export \"test\")))") 
instance = Instance(store, module, [])
test = instance.exports(store)["test"]
test(store)

Requires Python 3.9 or later; 64-bit builds only on Windows, macOS, or Linux with x86_64 or arm64 architecture.

Verify before relying:

- Exact scope and stability guarantees of the monthly major-version release cycle for production use.
- Whether the Apache-2.0 WITH LLVM-exception dual-license composition is compatible with your project's license requirements.
- Performance characteristics and memory overhead when executing WebAssembly modules from Python.

## Package facts

- License: Apache-2.0 WITH LLVM-exception (unclear)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 1.9M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

webassembly runtime python, wasm execution python, wasmtime python binding, run wasm modules python, webassembly interpreter python, wasm component python, bytecode alliance wasmtime, webassembly, runtime-embedding, bytecode-alliance

[View on SkillFed](https://skillfed.io/packages/wasmtime) · [View on PyPI](https://pypi.org/project/wasmtime/)