Readable, batteries-included, everywhere. Python powers web backends, data science and AI — and right here it runs for real in your browser.
No simulation here. We load Pyodide (CPython compiled to WebAssembly), so the editor below executes genuine Python. Edit the code and hit Run.
One line builds, filters and transforms a list. Load this snippet into the runner above (button below) and run it — the output is computed by the real interpreter.
# squares of even numbers 0..19 squares = [n*n for n in range(20) if n % 2 == 0] print(squares) print("sum =", sum(squares))
Define a function, call it, get real results. This recursive factorial runs in actual CPython via WebAssembly.
def factorial(n): return 1 if n <= 1 else n * factorial(n - 1) for n in [5, 10, 20]: print(f"{n}! = {factorial(n)}")
Clean syntax, a giant standard library, and the dominant ecosystem for data and AI.
print by redirecting sys.stdout); the snippets in Demos 02–03 load into that same real interpreter. The stats are factual context. The shared CSS shell provides the page styling.