Kodigo

A free online compiler that comes with guides. Write code, run it in your browser, and learn as you go, with nothing to install.

Status: Java, JavaScript, Python, C and C++ work end to end, each with guide buttons. You can open the site, pick a language, build a program with guide buttons, and run it.

Works now

• Java 21, compiled and run in your browser with the real javac
• JavaScript, Python 3.14 (Pyodide), and C and C++ (the real clang compiler), all running in your browser
• Output and errors shown separately, and compile errors get red marks in the editor, clickable line numbers, and a plain-English explanation of common errors
• Programs that read input with Scanner: type the input in the output panel, like a console
• Guide buttons on the right of the editor that insert code, like a for loop or a Scanner, each with a dropdown arrow that explains it
• A Stop button for programs that never finish
• A layout for phones, where the guide is a drawer at the bottom
• Light and dark themes: the site is dark until you press the toggle, and the choice is remembered on your device
• A warning before you close or refresh with unsaved changes. Nothing is saved, and the editor always starts from the starter code
• Code runs in your browser and is never sent to a server

See the roadmap for the current plan and architecture for how it works.