Cronoff: a free online code runner that works offline
Made by yehon106.
Cronoff lets you write and run code right in your web browser. There is nothing to install and no sign-up. Your code runs on your own device, so it keeps working when your internet goes away.
Languages that run in your browser
- Python (with pygame-style graphics, turtle and common packages)
- JavaScript and TypeScript (with a canvas for games)
- SQL, Lua, Ruby, C / C++, Scheme and Prolog
Java, C#, Go, Rust and Kotlin can also be run, but they need a code server and so need internet.
What you get
- Several files in tabs. Tabs can work together, so one file can import another.
- Several programs can run at the same time, each with its own console.
- Red markers for mistakes before you run, and clear errors with the line that failed.
- A built-in example game made of several files that import each other.
- Install it as an app on a computer, phone or tablet.
- An optional account to save your tabs online. You never have to log in.
Questions
Do I need an account?
No. Everything works without one. An account only adds saving your tabs online.
Is my code uploaded?
No. Code in the browser languages runs on your device. Only the online languages (Java, C#, Go, Rust, Kotlin) send code to a code server to run it.
What do you count?
Cronoff counts anonymous usage numbers such as visits and how many runs each language gets. No code, names or IP addresses are stored, and you can switch this off in the settings (the gear).
How do I install it as an app?
Press Install app at the top of Cronoff. On an iPhone or iPad use Share, then Add to Home Screen.