universalWasmLoader-py

Universal WASM loader for Python — the Python port of universalWasmLoader-js. Loads and instantiates WebAssembly modules and, when a companion .wit file is present, applies the Canonical ABI so you call WIT exports with idiomatic Python values (int/float, bool, str) instead of raw i32/pointer pairs.

• PyPI package: universal-wasm-loader
• WASM runtime: wasmtime ≥ 26.0.0
• License: MIT

Install

pip install universal-wasm-loader

Usage

wasm_import() loads a .wasm module and hands you its exports as a dict of ready-to-call Python functions — pull one out, bind it to a name, and call it like any other function:

import asyncio
from universal_wasm_loader import wasm_import

async def main():
    # Load the module. Exports come back as a dict of callables.
    exports = await wasm_import("./math.wasm")

    # Turn a WASM export into a Python function and call it.
    # (companion math.wit -> `calculate: func(a: s32, b: s32) -> s32`)
    calculate = exports["calculate"]
    print(calculate(1, 2))        # 3

asyncio.run(main())

When a companion <name>.wit sits next to the .wasm, the Canonical ABI is applied automatically: kebab-case WIT names become camelCase keys, and arguments and results are idiomatic Python values (bool, str) — no manual i32/pointer handling:

# strings_50.wasm + strings_50.wit -> greet, shout, str-len
exports = await wasm_import("./strings_50.wasm")

greet = exports["greet"]
print(greet("World"))             # "Hello, World!"   (str in, str out)
print(exports["strLen"]("hello")) # 5                 (WIT export `str-len`)

create_singleton() (one shared instance) and InstancePool() (N instances for concurrent workloads) are also exported. See the project on GitHub for the full API, examples, and source.