Pyodide vs a server sandbox can Pyodide run pip packages?

Which should you use, Pyodide or a server sandbox?

It depends on where the code should run and what it needs. When a model or agent writes the code, Runtime gives it a server sandbox. In that sandbox, any pip package, a subprocess, a compiler and the network work. Pick Pyodide when the code runs on the user's device, as in a browser notebook or a teaching exercise, with pure-Python or already-ported packages.

What Pyodide is

Pyodide is "a Python distribution for the browser and Node.js based on WebAssembly": CPython compiled to WebAssembly with Emscripten. Version 314.0.0, released 9 June 2026, moved it to Python 3.14.2; the current release on 26 October 2026 is 314.0.7, from 14 September 2026. When it runs in a browser, the project says, "Python has full access to the Web APIs."

It is a good fit for Python that should run on the user's own device: notebooks in the browser, teaching tools, and data work where the data never leaves the page.

Can Pyodide run pip packages?

Some of them. Pyodide installs packages with micropip. After Pyodide loads, "only the Python standard library is available." micropip installs:

• Pure-Python wheels from PyPI. The home page says "any pure Python package with a wheel available on PyPi is supported." A wheel ending in py3-none-any.whl is the sign.
• Packages built for Pyodide, the wasm32 Emscripten wheels. The project has ported many packages with C, C++ and Rust extensions. Its list for the current release includes NumPy 2.4.6, pandas 3.0.2, SciPy 1.18.0, Matplotlib 3.10.8, scikit-learn 1.8.0, DuckDB 1.5.1 and lxml 6.1.3.

Anything else fails. The FAQ says a package with "binary extensions (e.g. C, Fortran or Rust)" that nobody has built for Pyodide "needs to be cross-compiled for Pyodide." A wheel fetched from your own server needs CORS headers, or the browser blocks it.

What else does not work in Pyodide?

From Pyodide's own pages on WebAssembly constraints and its FAQ:

• No threads, processes or subprocesses. "Fork and pthreads do not work in Pyodide." Starting a thread, a multiprocessing worker or a subprocess raises RuntimeError. Code that calls git, ffmpeg or a compiler cannot run.
• Sockets, only experimentally, and only in Node.js. "By default, Pyodide does not support sockets in the browser." Node.js can enable an experimental socket API with useNodeSockFS().
• HTTP through the browser. Requests are "subject to the same limitations as any JavaScript network call": "very little or no control over certificates, timeouts, proxies", and CORS can block them.
• Missing standard modules. venv, ensurepip, termios, tkinter, curses, fcntl, resource and others are removed. ssl is "a stub implementation that does not use OpenSSL."

Side by side

Is Pyodide safe for untrusted code?

It depends on where it runs. In a browser, Pyodide code runs in the page with "full access to the Web APIs." So model-written code shares the page's origin and whatever the page can reach. In Node.js, it runs inside your server's process. A server sandbox keeps the code off your machines and your users' pages entirely.

When each fits

• Pick Pyodide when the code should run on the user's device: a browser notebook, a teaching exercise, or a chart from data the user dropped in, with pure-Python or already-ported packages.
• Pick a server sandbox when the code comes from a model or an agent and may need any package, a subprocess, a compiler, a database driver, the network or more memory than a browser tab. It is also the choice when the code must not run where your users' sessions live.

Run the same Python in a Runtime sandbox

Allow the package index, install what the code needs, then switch the network off before the model's code runs:

TypeScriptimport { Sandbox } from "withruntime";await using sbx = await Sandbox.create({  network: { internet: true, allow: ["pypi.org", "*.pythonhosted.org"] },  timeoutSeconds: 600,  onLeaseEnd: "stop",});await sbx.exec("pip install polars", { check: true, timeoutMs: 180_000 });await sbx.network.set({ internet: false });const run = await sbx.exec([  "python3",  "-c",  "import polars, subprocess; print(polars.__version__, subprocess.run(['nproc'], capture_output=True, text=True).stdout)",]);console.log(run.stdout);

Pythonfrom withruntime import Sandboxwith Sandbox.create(    network={"internet": True, "allow": ["pypi.org", "*.pythonhosted.org"]},    timeout_seconds=600,    on_lease_end="stop",) as sbx:    sbx.exec("pip install polars", check=True, timeout_ms=180_000)    sbx.network.set(internet=False)    run = sbx.exec([        "python3",        "-c",        "import polars, subprocess; print(polars.__version__, subprocess.run(['nproc'], capture_output=True, text=True).stdout)",    ])    print(run.stdout)

For a chat that runs Python turn after turn, the code interpreter keeps variables between cells and returns charts as PNG and data frames as tables (code interpreter for chatbots). NumPy, pandas and matplotlib are in the default image.

A new account gets 100 free hours of a 1 GB machine in its first 30 days, with no card:

Terminalnpx withruntime sandboxes run -- python3 -c 'import pandas; print(pandas.__version__)'

More: WebAssembly vs microVM, what is a code interpreter?, data analysis agent, Python SDK.

Sources

Checked 26 October 2026.

• Pyodide, changelog, loading packages, packages built in Pyodide
• WebAssembly constraints, FAQ, using sockets

Facts on this page were checked on 26 October 2026.