Is PyRun completely free to use?

Yes — PyRun is entirely free. There is no sign-up, no subscription, and no hidden limit. You can write and run Python code as many times as you like without creating an account.

Does PyRun work without an internet connection?

After the first load, PyRun continues to work offline. The Python engine (Pyodide) is cached locally by your browser, so you can keep coding even when you have no internet access. Some features like link sharing require a connection.

Which version of Python does PyRun use?

PyRun runs Python 3.11 via Pyodide, a port of CPython compiled to WebAssembly. You get access to the full Python standard library, including modules like math, json, datetime, itertools, and more.

Is my code private? Does PyRun store what I write?

Your code never leaves your device unless you explicitly generate a public share link. All execution happens entirely inside your browser sandbox. PyRun has no server that receives or stores your code.

Can I use PyRun on a phone or tablet?

Yes. PyRun is built with a responsive layout and works on mobile browsers. The interface adapts to smaller screens, switching to a stacked layout so both the editor and output terminal remain accessible.

Can I import and open my own Python files?

Absolutely. You can open any .py file from your device using the toolbar button or with the Ctrl+O keyboard shortcut. The file loads directly into the editor, ready to run.

How do I share my code with someone else?

Use the Share button in the toolbar or press Ctrl+H. PyRun generates a unique URL that encodes your code. Anyone with the link can open it in their browser and see (or run) the exact same code.

Does PyRun support the input() function?

Yes. PyRun has full support for Python's built-in input() function. When your code reaches an input() call, the terminal prompts you to type a response, just as it would in a local terminal.

attrs

Utilities

Class boilerplate-free

Try attrs in PyRun

What is attrs?

attrs (imported as attr) is a Python package that lets you write concise, correct Python classes without boilerplate. It automatically generates __init__, __repr__, __eq__, and other dunder methods, and additionally supports validators, converters, slots, and frozen (immutable) classes.

attrs is a popular choice for defining clean data-holding classes in Python, and it directly inspired Python's built-in dataclasses module. In PyRun, attrs loads instantly via micropip, making it a great library to explore when learning about class design patterns.

Code Example

Clean Python classes with attrs validators.

Attrs Data Classes

Try in Editor

import attr

@attr.s(auto_attribs=True)
class Point:
    x: float
    y: float

    def distance_to(self, other: "Point") -> float:
        return ((self.x - other.x)**2 + (self.y - other.y)**2)**0.5

@attr.s(auto_attribs=True)
class Polygon:
    name: str
    vertices: list = attr.Factory(list)

    def perimeter(self) -> float:
        pts = self.vertices + [self.vertices[0]]
        return sum(pts[i].distance_to(pts[i+1]) for i in range(len(pts)-1))

triangle = Polygon("Triangle", [
    Point(0, 0), Point(4, 0), Point(0, 3)
])

print(repr(triangle))
print(f"Perimeter: {triangle.perimeter():.4f}")
print(f"Expected : 12.0000  (3-4-5 right triangle)")

Why run attrs in PyRun?

✦ Zero setup — no pip install, no virtual environment, no Python download
✦ Instant results — powered by WebAssembly, runs locally in your browser
✦ Share your code — generate a link and anyone can run it instantly
✦ Works offline — after first load, PyRun runs without internet

Open editor with attrs example

Related Packages

faker

All packages Open Editor