Free, private, in your browser
Every program runs on your own device, inside a sandbox with no network access: nothing you write is uploaded, and there is no sign-up. What you type is saved on this device, and Share makes a link that carries your code and its input.
Each compiler has an input box, test cases with a line-by-line difference, error messages explained in plain words with the usual fix, and a button that opens the same run in the step-by-step visualizer, so you can see why a program does what it does.
Languages
- Online Python compiler: Python 3 with the standard library: input(), files, classes and exceptions.
- Online C compiler: scanf and printf, pointers, structs, malloc and files, with memory mistakes explained.
- Online C++ compiler: Classes, templates, the STL, cin and cout, fstream and exceptions.
- Online Java compiler: Classes, inheritance, generics, collections, lambdas and streams, with javac's own error messages.
- Online SQL compiler: SQLite: create tables, add data and see every query's result as a table.
- Online JavaScript compiler: console.log and prompt(), classes, Maps, promises and async/await.
- Online 8086 Assembly compiler: 8086 in MASM/TASM style, with DOS input and output and every register shown.
See also
- The code visualizer: run code one step at a time and see its memory.
- Practice problems, checked against hidden tests.