Thonny Online is a modern, browser-based adaptation of the Thonny Python IDE — offering the same simple, beginner-friendly Python editor directly on the web. Powered by WebAssembly and Pyodide, it provides a familiar Thonny-like experience without installation
What is Thonny Online?
Thonny Online is a browser-based adaptation of the popular Thonny IDE, built for beginners, students, and educators who want a simple and accessible way to learn Python. Instead of relying on remote servers, Thonny Online uses Pyodide and WebAssembly to run Python directly inside your browser.
This approach provides a fast, private, installation-free coding environment—ideal for learning Python, experimenting with code, or teaching in the classroom. While not a complete replacement for the full desktop Thonny IDE due to certain browser limitations, it successfully captures most of Thonny’s core features and offers a familiar, beginner-friendly experience entirely on the web.
Key Features
Zero Installation
Start coding instantly. No Python installation, environment setup, or configuration required. Just open the URL and code.
Interactive Shell
Experiment with code snippets and inspect values in real-time using the built-in Python REPL shell.
Variable Inspector
Visualize your program's state. See variable names and values update automatically as your code executes.
Structure Outline
Navigate your code easily with the Outline view, showing functions and classes in a hierarchical tree.
Data Plotter
Visualize numerical data simply by printing numbers to the shell. Detects and plots values automatically.
Browser-Based Privacy
Your code runs locally in your browser using WebAssembly. No code is sent to a remote server, ensuring privacy.
Program Tree (AST)
View the abstract syntax tree of your code to better understand how the Python interpreter parses your syntax.
Package Management
Install and use pure Python packages from PyPI using Micropip, extending the capabilities of the editor.
This Website vs Thonny IDE
While Thonny Online strives to replicate the desktop experience, running in a browser environment comes with specific architectural differences.
Feature
Desktop Thonny
Thonny Online
Execution Engine
Native OS Process
Browser (WebAssembly)
File System
Full Disk Access
Virtual / LocalStorage
Network Access
Unrestricted
Restricted (CORS)
Step Debugger
Full Stepping
Limited / AST View
External C Modules
Supported
Pre-compiled only
Frequently Asked Questions
Find quick answers to common questions about Thonny Online's features, including how to run code, visualize data, manage files, and install packages. Whether you're a student or an educator, this guide helps you get the most out of your browser-based Python environment.
Just press F5 on your keyboard or click the green Run button in the toolbar. Your script executes instantly in the browser using Pyodide, and output appears in the Shell panel below.
If your code is stuck in an infinite loop or taking too long, click the red Stop button in the toolbar. This will terminate the execution immediately.
First, enable the Plotter from the View menu. Then, simply print numbers in your code (e.g., print(math.sin(x))). The Plotter automatically detects these numbers on standard output and draws a real-time line chart. It's perfect for visualizing sensor data, math functions, or simulations.
Go to View -> Outline to open the sidebar panel. This view automatically parses your code to show a hierarchical tree of classes, functions, and methods. Clicking on any item will scroll the editor directly to its definition.
The Variables panel (View -> Variables) shows the current state of all global variables in your program. It updates automatically after execution finishes or when using the interactive shell.
Yes! Use the File -> New menu or the + toolbar icon to create up to 5 files. You can switch between them using tabs at the top of the editor. Files are saved locally in your browser's storage, so they persist even if you refresh the page.
Click the Save icon or press Ctrl+S to save your current file. To open a local file from your computer, click the Upload icon (folder with arrow). Note that "saving" persists the file to your browser's local storage, not your computer's hard drive.
Open Tools -> Manage packages.... You can search for and install packages from PyPI. Note that only "pure Python" wheels or packages pre-compiled for Pyodide (like numpy, pandas, scipy, matplotlib) are supported. Binary extensions not ported to WebAssembly will not work.
Simply add comments starting with # TODO or # FIXME in your code. Enable the TODO view (View -> TODO) to see a list of all these items. detailed with their line numbers. Clicking an item jumps to that line.
The Program Tree view (View -> Program Tree) visualizes the Abstract Syntax Tree of your code. This is useful for educational purposes to understand how Python parses your source code into a tree structure.
You can increase or decrease the editor font size from the View menu, or use the shortcuts Ctrl + and Ctrl -.
Currently, interactive input() is not fully supported in the script runner causing it to hang or return default values. We recommend using hardcoded values or the interactive Shell for testing logic that requires input.
Yes. Thonny Online runs entirely in your browser using WebAssembly. Your code is never sent to a remote server for execution, ensuring your data and logic remain private.