Run your first package

Wasmer packages run from the CLI or inside JavaScript and Python applications. This guide uses the python/python package to calculate 1 + 1; no system Python installation is used inside the sandbox.

Install Wasmer

Choose the interface used by your host application:

On macOS or Linux:


curl https://get.wasmer.io -sSfL | sh

See Install Wasmer for Windows and other installation methods.


npm install @wasmer/sdk

Node.js and browser applications use the same package with different entrypoints. This example uses Node.js.


python -m pip install wasmer-sdk

Published wheels support macOS and Linux on arm64 and x86_64.

Run the package


wasmer run python/python@=3.13.18 -- -c "print(1+1)"

index.mjs


import { Wasmer } from '@wasmer/sdk/node';
 
const wasmer = new Wasmer();
const sandbox = await wasmer.sandboxes.create({
  packages: ['python/python@=3.13.18'],
});
 
const output = await sandbox
  .command('python', ['-c', 'print(1+1)'])
  .run();
 
console.log(output.text());
await sandbox.close();
await wasmer.close();

main.py


import asyncio
 
from wasmer_sdk import Wasmer
 
 
async def main() -> None:
    wasmer = Wasmer()
    sandbox = await wasmer.sandboxes.create(
        packages=['python/python@=3.13.18'],
    )
 
    output = await sandbox.command(
        'python', ['-c', 'print(1+1)']
    ).run()
    print(output.text())
 
    await sandbox.close()
    await wasmer.close()
 
 
asyncio.run(main())

Each example prints 2. The @= syntax pins the exact registry package version so every run resolves the same artifact.

A sandbox can combine multiple packages and expose files, streams, networking, and long-running processes. Continue with the JavaScript SDK or Python SDK guide.

You can also publish your own package to run it through the CLI and every SDK.