WebTigerPython: A Low-Floor High-Ceiling Python IDE for the Browser

The shift to BYOD (bring your own device) policies at schools requires browser-based programming tools that balance accessibility and functionality. We introduce WebTigerPython, a Python IDE combining novice-friendly features (Turtle graphics, robotics, error messages) with advanced capabilities (NumPy, Matplotlib). Its client-side execution and web worker architecture ensure non-blocking interactivity. Python code is run in WebAssembly, performing only about three times slower than native CPython but significantly faster than other web-based IDEs to which we compared it. Deployed in classrooms with 800+ daily users, WebTigerPython supports offline use, URL-based sharing of code, and aligns with existing curricula—demonstrating how web tools can rival local IDEs without compromising power or accessibility.