PlayGround

A Browser-based Python Runner playground powered by Pyodide. Try Python code in your web browser. No server, No account, or No payment is required.

Client Side Python is a browser-based Python playground powered by Pyodide.
Python code runs inside your browser tab (WebAssembly, no backend).

This makes it useful for:

• Quickly trying out small Python snippets
• Demonstrating Python basics in a classroom or workshop
• Experimenting with simple numeric or scripting tasks in a safe sandbox
• Showing how WebAssembly + Pyodide can bring “real” Python to the browser

• Fully client-side execution

  • Uses Pyodide to run CPython in WebAssembly.
  • No server, No database, No authentication required by default.

• Simple code editor + console

  • Text area for Python code.
  • Console area that shows stdout and stderr.
  • Buttons: Run, Stop, Clear, Load Sample, Copy Output.

• Responsive web UI

  • Built with Expo / React Native Web.
  • Layout adapts to different viewport sizes (desktop / tablet).

• Deterministic CI via Docker

  • Jest tests run in a Docker container.

On first load, the app:

1. Fetches Pyodide from a CDN.
2. Initializes the Pyodide runtime and exposes runPythonAsync.
3. Attaches custom handlers for stdout and stderr so that Python output is streamed into the in-page console.
4. Uses a simple execution token to implement a soft Stop:
   • Each run increments an internal execId.
   • If a run finishes with an outdated execId, its output is discarded.
   • This prevents stale results from older runs from polluting the console.

All of this happens in the browser, without any backend API calls.

• Docker & Docker Compose

# set environment variables:
export REACT_NATIVE_PACKAGER_HOSTNAME=${YOUR_HOST}

# Build the image
docker compose build

# Run the container
docker compose up

docker compose \
-f docker-compose.test.yml up \
--build --exit-code-from \
frontend_test 

• Apache License 2.0