Local Python runtime

Online Python Simulator

Write and run multi-file Python projects online in a private browser IDE with a file explorer, autocomplete, package support, console output, and local storage.

Local code tester

Python browser IDE

Write and run a local Python project with a file explorer, context-aware autocomplete, automatic package loading, stoppable execution, and persistent browser storage.

Runs in your browser

Ln 1, Col 1Run: Ctrl/Command + Enter · Suggestions: Ctrl/Command + SpaceDrafts save locally

main.py

from statistics import mean

scores = [82, 91, 88, 95, 79]
average = mean(scores)

print(f"Scores: {scores}")
print(f"Average: {average:.1f}")

Output

Press Run to load Python locally.

Available Python libraries

Import-ready Python packages

Third-party packages are downloaded from CmdMemo only when imported, so the simulator starts with a lightweight runtime and adds libraries as your code needs them.

13 featured packages

NumPy

v2.4.3

N-dimensional arrays, vectorized calculations, linear algebra, and numerical utilities.

import numpy

Pandas

v3.0.2

DataFrames, tabular data cleaning, grouping, joining, and time-series analysis.

import pandas

SciPy

v1.18.0

Scientific computing tools for optimization, integration, statistics, signals, and sparse data.

import scipy

Matplotlib

v3.10.8

Charts and data visualizations rendered with a browser-compatible backend.

import matplotlib

scikit-learn

v1.8.0

Machine-learning preprocessing, models, metrics, pipelines, and sample datasets.

import sklearn

SymPy

v1.14.0

Symbolic mathematics, algebra, calculus, equations, and exact arithmetic.

import sympy

NetworkX

v3.6.1

Graph structures, traversal algorithms, network analysis, and graph generators.

import networkx

Pillow

v12.2.0

Image creation, decoding, transformation, filtering, and format conversion.

import PIL

Beautiful Soup

v4.14.3

HTML and XML parsing, document traversal, and data extraction.

import bs4

Requests

v2.33.1

Familiar HTTP request APIs, subject to browser networking and cross-origin restrictions.

import requests

Regex

v2026.3.32

Advanced regular expressions beyond Python's built-in re module.

import regex

Pytest

v9.0.2

Concise tests, fixtures, parametrization, assertions, and test discovery.

import pytest

xarray

v2026.2.0

Labeled multidimensional arrays and dataset-oriented data analysis.

import xarray

Supporting packages loaded as dependencies (28)

Python playground guide

Run Python without installing Python

Use a complete browser-based workspace for quick scripts, data experiments, package examples, and Matplotlib charts. Your code executes on this device, with no account or local Python setup required.

Runtime: Browser worker
Packages: Loaded on demand
Output: Console and plots

Build a small project

Create folders and files in the Explorer or import an existing local project. Autocomplete recognizes imports, aliases, library APIs, call signatures, and variables defined in the active Python file.

Run in an isolated worker

Press Run or Ctrl/Command + Enter. Pyodide starts locally, inspects imports, and fetches self-hosted package wheels from CmdMemo only when your script needs them.

Inspect, refine, and keep

Read standard output and errors in the console, view Matplotlib figures below it, stop long-running code, copy results, or download the current editor as a reusable .py file.

Private by design

Your draft stays on this device

The dedicated simulator saves the project tree and editable files in local browser storage so they can survive a refresh. Reset restores the starter project; Clear empties only the active editor without sending anything to CmdMemo.

This is a browser runtime rather than a full operating system. Interactive terminal input, subprocesses, native system tools, unrestricted networking, and packages not built for Pyodide may be unavailable.