ExtensionsPython RunnerOnline

Run Python online in your browser

A free online Python interpreter: paste your code, press Run and read the output. It runs CPython on your device, in WebAssembly, and your code is not uploaded anywhere.

Tab inserts four spaces, Shift+Tab outdents, Ctrl/Cmd+Enter runs.

One line per input() call, typed before you press Run.

Press Run. The first run downloads Python (about 14 MB), once.

How it works
The tool above is a real Python interpreter online: CPython 3.14, the reference implementation of Python, compiled to WebAssembly and served from this site. On your first Run the page downloads the interpreter (about 14 MB, once, and the browser caches it), so later runs skip the download.
Your code executes in this tab, on your device, the same way the Python Runner extension runs it offline. Nothing you type is sent to a server: the page makes no requests except fetching the interpreter files from pinwisp.com, sets no cookies and keeps no history of what you ran.
Each run starts from a fresh namespace, so variables from one script never leak into the next. Errors print a real CPython traceback with the line numbers of your script, and input() reads the lines of the standard input field one by one.
What it can't do
  • Standard library only: numpy, pandas, requests and other pip packages are not available.
  • Python code cannot reach other websites or APIs, and files do not survive a reload of the page.
  • No graphics output, so matplotlib windows and turtle are out of scope.
  • It runs a whole script at a time rather than one line at a time like an interactive console.
  • Stopping a runaway script restarts the interpreter, which takes a moment on the next run.
Questions
Is the online Python runner free?
Yes. There is no account, no sign-up and no limit on runs. The page downloads the Python interpreter from this site once, then runs your code in your browser.
Is my code uploaded anywhere?
No. The code runs in this browser tab, on your device: the interpreter is CPython compiled to WebAssembly. The page sets no cookies, sends no analytics and stores nothing: closing the tab clears everything.
Can I install packages with pip?
No. This runner ships the Python standard library only, like the Python Runner extension: numpy, pandas and requests are not available, and Python code cannot reach other websites to fetch them. Scripts that need only json, datetime, re, itertools, csv or the rest of the standard library run fine.
Which Python version is this?
Python 3.14.2, the same CPython build the Python Runner extension ships (Pyodide 314.0.7). The status line under the output shows the exact version once the interpreter is ready.
Need it offline?
Python Runner for Chrome runs the same engine in an extension tab: it works without a connection, keeps your snippets on your device and adds a right-click "Run selected Python" on any page.
Open the Python Runner page