🐍Online Python Compiler

What this tool is

A lightweight place to write and run Python programs: an editor with syntax highlighting, a terminal for output and a file panel. It is handy when you want to test a snippet, practise an exercise or show someone a working example.

Your files are saved in your browser's storage, so after a refresh you are back where you left off.

How it works

Under the hood it uses Pyodide — the CPython interpreter compiled to WebAssembly. Your browser downloads it once (the first visit can take a few seconds) and then runs your code locally, on your own computer or phone.

Your code is not sent to a server to be executed. That is why results appear instantly, and why programs cannot touch files on your disk — they only see files created in the “Files” panel.

What you can do

The interpreter covers most of what you need for lessons and small projects:

• input() — the program pauses and waits for an answer typed into the terminal.
• Packages without setup: import numpy, pandas, matplotlib, scipy or sympy and they install themselves on the first run. Anything else from PyPI that is pure Python can be added in the “Packages” panel (micropip).
• Share your code with a link — the “Share” button copies a URL that opens your program in this editor for anyone you send it to.
• Download the current file as a .py file and keep working on it in any other editor.
• Several files in one project — create a helper module and import it from main.py, or read and write text files.
• Charts and images — plt.show() from matplotlib draws the chart in the terminal, and saved PNG/JPG files can be opened in the editor.
• The “Stop” button interrupts a program stuck in an infinite loop.

Limitations

Python in the browser runs in a sandbox, so not everything behaves as it does on a desktop install:

• Threads and processes (threading, multiprocessing) do not work as they do on a computer — code runs on a single thread.
• Network access is limited: there are no sockets, and HTTP requests are subject to browser security rules (CORS).
• Packages with native code work only if they have been built for Pyodide (for example numpy, pandas, matplotlib). Libraries such as TensorFlow or tkinter are not available.
• Very heavy computations will be slower than in regular Python installed on your machine.

Who it is for

Students who cannot install software on a school computer, and teachers who want the whole class to start coding at the same moment.

Anyone preparing for a computer science exam — practise algorithms, lists and processing text files with data, then move the same code to the environment used in the exam.

Beginners who want to find out whether they enjoy programming before setting up an editor and installing Python.

Examples to run

Click “Open in editor” to load an example into example.py, then run it and change it however you like.

from datetime import date

name = input("What is your name? ")
year = int(input("What year were you born? "))
age = date.today().year - year
print(f"Hi, {name}! This year you turn {age}.")

grades = [5, 4, 3, 5, 6, 4, 5]

average = sum(grades) / len(grades)
print(f"Average: {average:.2f}")

for grade in sorted(set(grades)):
    print(grade, "*" * grades.count(grade))

def is_prime(n):
    if n < 2:
        return False
    d = 2
    while d * d <= n:
        if n % d == 0:
            return False
        d += 1
    return True

print([n for n in range(50) if is_prime(n)])

with open("results.txt", "w") as f:
    for x in range(1, 6):
        f.write(f"{x} {x ** 2}\n")

with open("results.txt") as f:
    for line in f:
        x, square = line.split()
        print(f"{x}^2 = {square}")

import matplotlib.pyplot as plt

x = list(range(-5, 6))
y = [v ** 2 for v in x]

plt.plot(x, y, marker="o")
plt.title("y = x²")
plt.grid(True)
plt.show()

Frequently asked questions